Late Permian nautiloids from Julfa (NW Iran)

Late Permian nautiloids from Julfa (NW Iran) Dieter KORN 1,* & Abbas GHADERI 2,* 1 Museum für Naturkunde, Leibniz Institut for Research on Evolution and Biodiversity, Invalidenstraße 43, 10115 Berlin, Germany. 2 Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Azadi Square, 9177948974 Mashhad, Iran. * Corresponding authors: dieter[email protected], [email protected] Abstract. The Late Permian Julfa and Ali Bashi formations of sections near Julfa (NW Iran) have yielded diverse nautiloid assemblages. These come from the early Wuchiapingian Araxoceras Beds (19 species), the late Wuchiapingian Vedioceras Beds (six species), the early Changhsingian Dzhulfites Beds (three species) and the late Changhsingian Paratirolites Limestone (two species). These species belong to 20 genera, eight of which are new: Fididomatoceras gen. nov., Azarinautilus gen. nov., Serometacoceras gen. nov., Alibashinautilus gen. nov., Tardunautilus gen. nov., Corotainoceras gen. nov., Celeroliroceras gen. nov., Julfanautilus gen. nov. A total of 30 species are described, of which 24 are new: Domatoceras elegantulum sp. nov., Domatoceras multituberculatum sp. nov., Permodomatoceras hamdii sp. nov., Fididomatoceras intracostatum gen. et sp. nov., Azarinautilus nahidae gen. et sp. nov., Aifinautilus hebes sp. nov., Serometacoceras cingulum gen. et sp. nov., Serometacoceras inflatum gen. et sp. nov., Serometacoceras parvituberculatum gen. et sp. nov., Serometacoceras arasense gen. et sp. nov., Alibashinautilus vetus gen. et sp. nov., Alibashinautilus ambiguus gen. et sp. nov., Tardunautilus nimius gen. et sp. nov., Tardunautilus minor gen. et sp. nov., Tainoceras admonens sp. nov., Tainoceras latecostatum sp. nov., Tainoceras unitum sp. nov., Corotainoceras inerme gen. et sp. nov., Tainionautilus deinceps sp. nov., Liroceras choopani sp. nov., Celeroliroceras celere gen. et sp. nov., Peripetoceras parum sp. nov., Julfanautilus ashourii gen. et sp. nov. and Julfanautilus hairapetiani gen. et sp. nov. The new family Julfanautilidae fam. nov. is erected to accommodate the species of Julfanautilus gen. nov. With 30 species, the assemblage from the area around Julfa is one of the most diverse Late Permian occurrences of coiled nautiloids. With 25 Wuchiapingian species alone, it is the most species-rich assemblage for this interval. Keywords. Nautiloidea, Nautilida, Permian, Iran, morphology. Korn D. & Ghaderi A. 2025. Late Permian nautiloids from Julfa (NW Iran). European Journal of Taxonomy 1018: 1–113. https://doi.org/10.5852/ejt.2025.1018.3069 1 European Journal of Taxonomy 1018: 1–113 https://doi.org/10.5852/ejt.2025.1018.3069 europeanjournaloftaxonomy.eu ISSN 2118-9773 2025 · Korn D. & Ghaderi A. This work is licensed under a Creative Commons Attribution License (CC BY 4.0) Received: 25 August 2024 • Accepted: 7 April 2025 • Published: 24 September 2025 Topic editor: Marie-Béatrice Forel • Desk editor: Kristiaan Hoedemakers Monograph urn:lsid:zoobank.org:pub:74A6C5AD-7328-444C-9478-36F290657B6E Introduction Late Permian nautiloids have a wide geographical distribution, but species-rich occurrences are restricted to a few regions. After the probably first description of the Late Permian nautiloid “Nautilus Freieslebeni” from the Central European Zechstein Formation by Geinitz (1841), it took several decades until almost simultaneously Mojsisovics (1869), Stache (1877), Abich (1878), Waagen (1879) and Kayser (1883) described further and sometimes more species-rich occurrences from the Dolomites (Italy), Transcaucasia (Azerbaijan), the Salt Range (Pakistan) and Jiangxi (South China), respectively. Despite the growing interest in the transition from the Palaeozoic to the Mesozoic since the end of the 19th century, it took decades to publish more comprehensive studies of Late Permian nautiloids. Reed (1931, 1944) revised the assemblages from the Salt Range and described new species. For the sites near the Araxes River in the Transcaucasus, it took even longer until the 1960s (Shimansky 1962c, 1965b). In the last decades, rather diverse Late Permian nautiloid assemblages were described from two regions: (1) South China: Xu (1977), Zhao et al. (1978), Liang (1984), Zheng (1984), Qin (1986), Yang et al. (1987), Wu & Kuang (1992) and Miao et al. (2021) described species-rich assemblages from various places and different facies in the Jiangxi, Zhejiang, Anhui, Hubei, Sichuan, Guizhou, Hunan and Guangxi provinces. (2) Dolomites: Posenato & Prinoth (2004) and Prinoth & Posenato (2007) described a moderately large suite of nautiloids from the Changhsingian Bellerophon Formation and separated between eight species within five genera. In the following, we describe newly assembled nautiloid collections from the south side of the Aras (= Araxes) river in north-western Iran (Fig. 1). These new finds come from four general stratigraphic units, (1) the early Wuchiapingian beds characterised by the ammonoid genus Araxoceras Ruzhencev, 1959, (2) the late Wuchiapingian beds with the ammonoid Vedioceras Ruzhencev, 1962, (3) the early Changhsingian beds characterised by the ammonoids Iranites Teichert & Kummel, 1973, Dzhulfites Shevyrev, 1965 and Shevyrevites Teichert & Kummel, 1973 and (4) the late Changhsingian Paratirolites Limestone (Fig. 2). This is the most stratigraphically detailed Late Permian nautiloid succession known from a single region. Fig. 1. Geographical position of Permian-Triassic boundary sections in the Transcaucasus-NW Iran region (after Arakelyan et al. 1965); the red dots represent the sections investigated in this study (from Korn et al. 2016). European Journal of Taxonomy 1018: 1–113 (2025) 2 This study complements the previous work in the sections around Julfa, which was carried out as part of a project supported by the German Research Foundation. These studies examined the general sedimentary succession and ecological changes (Leda et al. 2014; Schobben et al. 2015; Gliwa et al. 2020), palaeoclimatic changes (Schobben et al. 2014; Gliwa et al. 2022), succession and diversity of brachiopods (Ghaderi et al. 2014, 2015), ammonoids (Korn et al. 2016; Kiessling et al. 2018; Korn & Ghaderi 2019; Korn et al. 2019; Ghanizadeh Tabrizi et al. 2021), conodonts (Isaa et al. 2016; Gliwa et al. 2020) and ostracods (Gliwa et al. 2021). Historical review A detailed historical review of the earlier studies of nautiloids from Transcaucasia, and in particular from sites in the Aras Valley, was given by Teichert & Kummel (1973). They discussed the previous Fig. 2. Stratigraphical positions of the Late Permian nautiloid taxa from the region of Julfa. Arax = Araxoceras Beds; Vedi = Vedioceras Beds; Dzhu = Dzhulfites Beds; Para = Paratirolites Limestone. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 3 pioneering studies, which mainly focused on the famous Dorasham locality, 10–16 km west of the towns of Dzhulfa (Nakhichevan Province, Azerbaijan) and Julfa (East Azerbaijan Province, Iran) on the northern side of the Aras River. In the first description of nautiloids from Dorasham, Abich (1878) distinguished between 18 species (Figs 3–5), six of which are straight and 12 are coiled (original names and revisions): “Nautilus excentricus Eichwald” = Permonautilus abichi (Kruglov, 1928) “Nautilus propinquus, nov. form.” = Permonautilus abichi (Kruglov, 1928) “Nautilus parallelus, nov. form.” = Domatoceras parallelum (Abich, 1878) Fig. 3. Reproductions of nautiloid figures of Abich (1878). A. “Nautilus dorso plicatus” Abich, 1878. B. “Nautilus dorso plicatus”. C. “Nautilus dorso armatus” Abich, 1878. D. “Nautilus incertus” von Arthaber, 1900. E. “Nautilus Pichleri” von Arthaber, 1900. F. “Nautilus tubercularis” Abich, 1878. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 4 “Nautilus convergens, nov. form.” = Domatoceras convergens (Abich, 1878) “Nautilus concavus Sowerby” = Permonautilus abichi (Kruglov, 1928) “Nautilus dolerus, nov. form.” = unknown “Nautilus dorso armatus, nov. form.” = Serometacoceras dorsoarmatum (Abich, 1878) gen. et comb. nov. “Nautilus Pichleri von Hauer” = Serometacoceras verae (von Arthaber, 1900) gen. et comb. nov. “Nautilus tubercularis, nov. form.” = Serometacoceras tubercularis (Abich, 1878) gen. et comb. nov. “Nautilus dorso plicatus, nov. form.” = Tainoceras dorsoplicatum (Abich, 1878) “Nautilus armeniacus, nov. form.” = Pseudotitanoceras armeniacum (Abich, 1878) “Nautilus incertus” = Serometacoceras verae (von Arthaber, 1900) Von Arthaber (1900) added the new coiled nautiloid species “Pleuronautilus Verae”, now Serometacoceras verae (von Arthaber, 1900) gen. et comb. nov. and Stoyanow (1910) added one new straight nautiloid species and one additional first record of a coiled nautiloid. Fig. 4. Reproductions of nautiloid figures of Abich (1878). A. “Nautilus parallelus” Abich, 1878. B. “Nautilus convergens” Abich, 1878. C. “Nautilus armeniacus” Abich, 1878. Scale bar units = 1 mm. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 5 The first monographic description of the Late Permian nautiloids from the Transcaucasus was published by Shimansky (1965b) who described 22 species of coiled nautiloids from the Araxoceras Beds, eleven from the Vedioceras Beds (both belonging to the Wuchiapingian), five from the “Phisonites Beds” (= Zal Member) and seven from the Paratirolites Limestone (both belonging to the Changhsingian). For the straight nautiloids, the respective numbers were 6, 2, 1 and 1. It must be kept in mind that 60 percent of the taxa listed by Shimansky (1965b: table 5) were held in open nomenclature. Nevertheless, Teichert & Kummel (1973) correctly stated that this is an impressive list, which demonstrates a high diversity, particularly for the lower Julfa beds (Araxoceras Beds). Teichert et al. (1973) and Teichert & Kummel (1973) investigated sections west of Julfa on the southern (Iranian) side of the Aras valley. They found essentially the same nautiloid assemblages, but comparison with the faunal list provided by Shimansky (1965b) shows that some taxa were missing, but also reported the presence of the three additional genera Temnocheilus, Tainionautilus and Titanoceras in the Iranian assemblages. After this study, nautiloids from the entire Transcaucasian region were only occasionally mentioned. Shimansky (1979b) added three additional taxa (Araxonautilus nodosus Shimansky, 1979, A. sp. and Pararhiphaeoceras probum Shimansky, 1979) to the species list of the Late Permian nautiloids of the Transcaucasus. Kotlyar et al. (1983) provided occurrence lists of Late Permian fossils from various places in Armenia and Azerbaijan including nautiloid species, but they did not provide illustrations of their material. Zakharov (in Kotlyar et al. 1989) described the new Middle Permian species “Pleuronautilus dzhagadzurensis Zakharov in Kotlyar et al., 1989”. Gliwa et al. (2020) illustrated a selection of the material described in the present study. Fig. 5. Reproductions of nautiloid figures of Abich (1878). A. “Nautilus concavus” Sowerby, 1840. B. “Nautilus concavus”. C. “Nautilus excentricus” Eichwald, 1857. D. “Nautilus propinquus” Kruglov, 1928. Scale bar units for all figures = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 6 Material and methods Specimens studied We investigated a total of 123 specimens from the Julfa and the Ali Bashi formations. The majority of the specimens were collected from float material below the outcrops. However, based on their lithology, all the specimens described here can be undoubtedly assigned to a member of the Julfa and Ali Bashi formations. Four members have been distinguished from bottom to top with the following species that are represented (Fig. 2): (1) Araxoceras Beds (early Wuchiapingian): light grey micritic nodular limestone (102 specimens) • Domatoceras elegantulum sp. nov. – 9 specimens • Domatoceras multituberculatum sp. nov. – 6 specimens • Domatoceras convergens (Abich, 1878) – 3 specimens • Permodomatoceras hamdii sp. nov. – 10 specimens • Fididomatoceras gracile (Shimansky, 1965) gen. et comb. nov. – 1 specimen • Fididomatoceras intracostatum gen. et sp. nov. – 2 specimens • Azarinautilus nahidae gen. et sp. nov. – 4 specimens • Aifinautilus hebes sp. nov. – 1 specimen • Serometacoceras dorsoarmatum (Abich, 1878) gen. et comb. nov. – 3 specimens • Serometacoceras dorashamense (Shimansky, 1965) gen. et comb. nov. – 16 specimens • Serometacoceras verae (von Arthaber, 1900) gen. et comb. nov. – 8 specimens • Serometacoceras cingulum gen. et sp. nov. – 1 specimen • Serometacoceras inflatum gen. et sp. nov. – 1 specimen • Alibashinautilus vetus gen. et sp. nov. – 3 specimens • Alibashinautilus sp. – 1 specimen • Tardunautilus minor gen. et sp. nov. – 1 specimen • Corotainoceras inerme gen. et sp. nov. – 1 specimen • Liroceras choopani sp. nov. – 6 specimens • Celeroliroceras celere gen. et sp. nov. – 1 specimen • Permonautilus abichi (Kruglov, 1928) – 24 specimens (2) Vedioceras Beds (late Wuchiapingian): pink or light grey nodular limestone (10 specimens) • Serometacoceras parvituberculatum gen. et sp. nov. – 1 specimen • Tainoceras admonens sp. nov. – 2 specimens • Tainoceras latecostatum sp. nov. – 1 specimen • Celeroliroceras sp. – 1 specimen • Peripetoceras parum sp. nov. – 2 specimens • Julfanautilus ashourii gen. et sp. nov. – 1 specimen • Julfanautilus hairapetiani gen. et sp. nov. – 1 specimen • gen. indet. sp. indet. – 1 specimen (3) Dzhulfites Beds (early Changhsingian): grey nodular limestone with high clay content (7 specimens) • Ocunautilus sp. – 2 specimens • Serometacoceras arasense gen. et sp. nov. – 1 specimen • Tardunautilus nimius gen. et sp. nov. – 1 specimen • New genus C to be described by Korn & Hairapetian (in press) – 1 specimen • Tainoceras unitum sp. nov. – 1 specimen • Tirolonautilus sp. 2 – 1 specimen (4) Paratirolites Limestone (late Changhsingian): pink to dark red nodular limestone (4 specimens) • Alibashinautilus ambiguus gen. et sp. nov. – 1 specimen • Tainionautilus deinceps sp. nov. – 1 specimen KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 7 • Tirolonautilus sp. 1 – 1 specimen • New genus F to be described by Korn & Hairapetian (in press) – 1 specimen Taxonomic concept For the order Nautilida in current understanding, several partially conflicting concepts of systematics have been published and modified over the decades. While Flower & Kummel (1950) and Kummel (1953, 1964) took a more conservative approach, Shimansky (1962a, 1962b, 1965b, 1967) proposed a much more detailed scheme. Dzik (1984) discussed the phylogeny and its implications for the systematic scheme in great detail and drew a much more complex evolutionary history of the coiled nautiloids. In a revision of the Carboniferous and Permian coiled nautiloids by Korn (2025), a new systematic scheme was presented. This scheme is largely based on the phylogenetic considerations of Ruzhencev & Shimansky (1954) as well as Dzik (1984) and is largely based, with some modifications, on the systematic scheme of Shimansky (1967, 1979a). This also means that it differs from the frequently used scheme of the Treatise on Invertebrate Paleontology (Kummel 1964). The description of the specimens follows the terminology of conch, ornament and suture line proposed by Korn (2010) and Klug et al. (2015) for the characterisation of ammonoids (Fig. 6). The terminology of conch geometry used here largely corresponds to that proposed by Teichert (1964). The only differences concern the following terms: umbilical angle or shoulder (= umbilical margin) and umbilical area (= umbilical width). The lists of genera and species are not exhaustive. When listing species within genera, the stratigraphic unit and the region of the type material have been added. Species have been named according to their original genus assignment. Abbreviations used in the species descriptions ah = apertural height dm = conch diameter IZR = imprint zone rate SD = septal density (distance of septa in degrees) uw = umbilical width WER = whorl expansion rate Fig. 6. Conch and suture line parameters used in the taxonomic descriptions. A. Conch parameters. B. Descriptive terms of whorl profiles. C. Suture line terminology. Abbreviation: 1. = lobe. European Journal of Taxonomy 1018: 1–113 (2025) 8 wh = whorl height ww = whorl width Abbreviations of the repositories MB.C. = Cephalopod collection of the Museum für Naturkunde, Berlin, Germany GLM = Golfaraj Ecomuseum, Julfa, Iran PIN = Palaeontological Institute of the Academy of Sciences, Moscow, Russian Federation LGI = Leningradskiy Gorniy Institut, Leningrad (now Sankt-Peterburgskiy Gorniy Universitet, St. Peterburg), Russian Federation Results Class Cephalopoda Cuvier, 1795 Subclass Nautiloidea Agassiz, 1847 Order Nautilida Agassiz, 1847 Diagnosis Exogastrically curved or coiled nautiloids with a conch shape ranging from gyroconic or cyrtoconic to more or less tightly coiled. Shell surface smooth or sculptured with a variety of elements (ribs, nodes, spines, longitudinal ridges or lines). Septa simply domed in most species, with the shape of the whorl profile producing suture lines with variable lobes and saddles. Variations in septal shape with inflexions producing deep lobes in some genera. Septal necks short and straight, rarely slightly widened. Connective rings cylindrical or beaded. Siphuncular or cameral deposits absent. Juvenile conch with cup-shaped initial chamber and narrow siphuncle. Morphological evolution includes the degree of coiling, the shape and size of the juvenile and adult conch and the suture line (after Shimansky 1962b; emended). Included suborders Nautilina Agassiz, 1847 (Jurassic to Recent); Solenochilina Flower, 1950 (Carboniferous to Permian); Liroceratina Flower, 1955 (Carboniferous to Jurassic); Rutoceratina Shimansky, 1957 (Devonian); Tainoceratina Shimansky, 1957 (Carboniferous to Triassic); Temnocheilina Flower, 1963 (Devonian to Permian); Domatoceratina Korn, 2025 (Carboniferous to Triassic). Suborder Domatoceratina Korn, 2025 Diagnosis Suborder of the order Nautilida, in which a ventrolateral shoulder and an umbilical margin are formed early in ontogeny. Conch usually discoidal, subinvolute to evolute. Juvenile whorl profile circular. Adult whorl profile subquadrate or inverted trapezoidal with a distinct ventrolateral shoulder and a distinct umbilical margin in the early species, showing modifications during evolution including a concave venter in some derived species. Dorsal whorl zone always present, but usually very small except for some derived species. Juvenile sculpture sometimes with radial ribs on the flank; adult sculpture is usually lacking except for elongate ventrolateral tubercles in derived species. Septa simply domed in most of the species; with septal inflexion or corrugated septa in some lineages. Suture line usually depending on the whorl profile, usually with shallow lobes and low saddles; with distinct lobes in one clade (from Korn 2025). Included superfamilies Grypoceratoidea Hyatt, 1900 (Carboniferous to Triassic); Permoceratoidea Miller & Collinson, 1953 (Permian); Subclymenioidea Shimansky, 1962 (Carboniferous). Remarks A detailed discussion of the Domatoceratina has been given by Korn (2025). KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 9 Fig. 9. Domatoceras multituberculatum sp. nov. from the Araxoceras Beds of the Julfa Formation. A. Holotype MB.C.31997 (Korn et al. 2011 Coll.) from Aras Valley, ventral and lateral views. B. The same specimen, reconstruction of apertural view. C. The same specimen, whorl profiles. D. The same specimen, suture line at ww = 26.6 mm, wh = 35.7 mm. E. Paratype MB.C.31999 (Ghaderi 2018 Coll.) from Aras Valley, whorl profile. F. The same specimen, suture line at ww = 13.2 mm, wh = 15.5 mm. G. Paratype MB.C.31998 (Ghaderi 2018 Coll.) from Aras Valley, lateral view. H. The same specimen, reconstruction of apertural view. I. The same specimen, suture line at ww = 20.1 mm, wh = 24.3 mm. J. Paratype MB.C.32000 (Ghaderi 2018 Coll.) from Aras Valley, whorl profile. K. The same specimen; suture line at ww = 19.5 mm, wh = 26.3 mm. L. Specimen MB.C.32002 (Ghaderi 2018 Coll.) from Ali Bashi 4, whorl profile. M. The same specimen; suture line at ww = 16.1 mm, wh = 20.0 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 16 There is no sculpture visible on the last whorl, but the two whorls before show shallow and broad ventrolateral tubercles, which in the third-last whorl even shows a prolongation into ribs that are connected with barely visible umbilical nodes. The specimen has rather narrowly standing septa; on the last quarter volution of the phragmocone there are nine septa with a trend to crowding at the end (SD ~ 10 degrees in average). The terminal suture line has a very shallow external lobe, a broadly rounded lateral lobe and a very shallow, ventrally inclined lobe on the umbilical wall (Fig. 9D). Paratype MB.C.31998 is, though incomplete, one of the best in the available material (Fig. 9G). It is a fully septate specimen with an estimated diameter of about 73 mm and allows the study of two whorls of the phragmocone. The estimated ww/dm and uw/dm ratios are 0.31 and 0.37, respectively. The whorl profile is weakly compressed (ww/wh = 0.79) with a nearly flat venter, a pronounced subangular ventrolateral shoulder and flattened, weakly convergent flanks. The whorls are widest at the narrowly rounded umbilical margin (Fig. 9H). The last whorl of the phragmocone appears to be free of sculpture, but the penultimate whorl shows rather coarse, low ventrolateral conical nodes, which are arranged in distances of about 15 degrees. The suture line has a very shallow external lobe, a subangular ventrolateral saddle (with a position at the ventrolateral shoulder) and a broadly rounded, shallow lateral lobe. Additionally, a very shallow, small and rounded lobe is visible on the umbilical wall (Fig. 9I). Both the last and the penultimate whorl show six chambers on a quarter of a volution (SD ~ 15 degrees). A complete suture line is visible in the fragmentary paratype MB.C.32000. It shows a rather narrow and shallow external lobe, a broadly rounded lateral lobe that has three times the depth of the external lobe. The specimen shows a rather narrow internal lobe of three quarters the depth of the lateral lobe (Fig. 9K). The smaller fragmentary paratypes MB.C.31999 (Fig. 9E–F) and MB.C.32002 (Fig. 9L–M) show the variation of the depth of the external lobe. Remarks Domatoceras multituberculatum sp. nov. differs from D. elegantulum sp. nov. in the conical ventrolateral nodes of the preadult whorls, the slightly more evolute and stouter conch, the less compressed whorl profile and the narrowly rounded umbilical margin. Domatoceras multituberculatum sp. nov. differs from D. convergens by the less strongly convergent flanks and the much wider whorl profile (ww/wh ~ 0.80 in contrast to D. convergens with ~ 0.60) at a conch diameter of 75 mm. The venter is much wider in D. elegantulum sp. nov. when compared to D. convergens. Table 2. Conch dimensions (in mm) and ratios of Domatoceras multituberculatum sp. nov.; reconstructed dimensions and ratios in italics. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.31997 100.9 27.2 37.3 38.6 35.6 0.27 0.73 0.38 2.39 0.05 MB.C.31997 – 23.8 30.3 – – – 0.79 – – – MB.C.31997 – 15.0 17.2 – – – 0.87 – – – MB.C.31998 75.9 21.8 27.6 28.5 26.1 0.29 0.79 0.38 2.32 0.05 MB.C.32000 – 20.4 26.4 – – – 0.77 – – – MB.C.32002 – 16.3 20.1 – – – 0.81 – – – MB.C.32001 – 15.1 18.8 – – – 0.80 – – – MB.C.31999 – 13.3 15.4 – – – 0.86 – – – KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 17 Domatoceras convergens (Abich, 1878) Fig. 10 Nautilus convergens Abich, 1878: 17, pl. 3 fig. 2. Domatoceras convergens – Shimansky 1965a: 41, pl. 15 fig. 9. Diagnosis Species of Domatoceras with extremely discoidal, subevolute and weakly compressed, inverted trapezoidal whorl profile (ww/wh ~ 0.60) at a conch diameter of 75 mm. Whorl profile with flat, very narrow venter, subangular ventrolateral shoulder, convergent, flattened flanks and broadly rounded umbilical margin. Suture line with a very narrow and very shallow external lobe and a much larger and deeper, broadly rounded lateral lobe. Material examined IRAN – West Azerbaijan • 1 specimen; Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 10; MB.C.32003 • 1 specimen; same data as for preceding; 2018; Ghaderi leg.; MB.C.32004. – East Azerbaijan • 1 specimen; Ali Bashi 4; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2010; Korn et al. leg.; MB.C.32005. Description Specimen MB.C.32003 is, though fragmentarily preserved, suitable for identification as it shows some specific characters (Fig. 10A). It has a whorl height of 26 mm and a ww/wh ratio of 0.57. The venter is flat and bordered by an angular ventrolateral shoulder; the flanks are weakly convex and converge from the rounded umbilical margin (Fig. 10B). The suture line shows a small and very shallow external lobe and a very wide, broadly rounded lateral lobe (Fig. 10C). Remarks Abich (1878: 17, pl. 3 fig. 2) described and illustrated, as “Nautilus convergens, nov. form.”, a fragment (less than a quarter of a volution) of an internal mould of 40 mm whorl height. From this, the conch shape can be reconstructed rather well. The inverted trapezoidal whorl profile is compressed (ww/wh = 0.62) and very weakly inflected dorsally by the preceding whorl. It is widest near the umbilical margin. The flanks converge rather rapidly and are separated from the flattened venter by a subangular ventrolateral shoulder. There is a shallow longitudinal groove on the outer portion of the flank just adjacent to the ventrolateral shoulder. No ornament can be seen. The suture line shows a broad rounded lobe on the flank and a very shallow lobe on the venter. Fig. 10. Domatoceras convergens (Abich, 1878), specimen MB.C.32003 (Ghaderi 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Aras Valley. A. Lateral view. B. Whorl profile. C. Suture line at ww = 14.5 mm, wh = 26.0 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 18 Domatoceras parallelum (Abich, 1878) Nautilus parallelus Abich, 1878: 17, pl. 2 fig. 2. Remarks “Nautilus parallelus, nov. form.” was described and illustrated by Abich (1878: 17, pl. 2 fig. 2). This illustration shows a fragment of less than half a volution of a specimen with a conch diameter of about 120 mm. Only the last whorl is preserved and this appears to be deformed or corroded on one side. Therefore, the conch shape cannot be precisely described. However, it can be seen that the umbilicus is rather wide (uw/dm ~ 0.45) and that the flanks are almost parallel. Specimens with this morphology have not been collected from NW Iran. Genus Permodomatoceras Ruzhencev & Shimansky, 1954 Type species Permodomatoceras trapezoidale Ruzhencev & Shimansky, 1954; original designation. Diagnosis Genus of the family Domatoceratidae with a subinvolute to subevolute conch. High to extremely high coiling rate; whorl profile weakly compressed or weakly depressed. Venter flattened or weakly concave, flanks usually flattened and slightly convergent; umbilical margin rounded or angular. Without sculpture. Suture line with small and shallow external lobe and broadly rounded lateral lobe; without annular process. Included species South Urals (Kruglov 1928; Ruzhencev & Shimansky 1954; Barskov et al. 2014): Domatoceras Fredericksi Kruglov, 1928, Artinskian, South Urals; Permodomatoceras trapezoidale Ruzhencev & Shimansky, 1954, Artinskian; Permodomatoceras permianum Barskov & Shilovsky in Barskov et al., 2014, Roadian; Permodomatoceras marielense Barskov & Shilovsky in Barskov et al., 2014, Roadian. Transcaucasia (this paper): Permodomatoceras hamdii sp. nov., Wuchiapingian, NW Iran. Himalayas (Diener 1903): Nautilus hunicus Diener, 1903, Wuchiapingian. Timor (Haniel 1915): Discites Arthaberi Haniel, 1915, Kungurian. Remarks According to Ruzhencev & Shimansky (1954: 95), Permodomatoceras is distinguished from Domatoceras by its more angular and lower whorls; the ratio of whorl width to height is between 0.90 and 1.10 in Permodomatoceras and only about 0.70 in Domatoceras. In addition, the external lobe is less well developed in Permodomatoceras. Permodomatoceras is thought to be closer to the American genera Penascoceras and Parapenascoceras in terms of whorl profile, but is clearly distinguished from them by a greater amplitude of suture elements and longer chambers. Permodomatoceras hamdii sp. nov. urn:lsid:zoobank.org:act:C3FB68E4-18D0-4B64-946A-75FE355723EA Fig. 11; Table 3 Domatoceras hunicum – Shimansky 1965b: 161, pl. 15 fig. 12. — Teichert & Kummel 1973: 421, pl. 1 figs 7–8, pl. 2 figs 3–4. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 19 Diagnosis Species of Permodomatoceras with extremely discoidal, subevolute conch (ww/dm ~ 0.30; uw/dm ~ 0.40), weakly compressed whorl profile (ww/wh ~ 0.80) and very high coiling rate (WER ~ 2.45) at a conch diameter of 80 mm. Whorl profile with weakly concave venter, subangular ventrolateral shoulder, gently convergent, flattened flanks and narrowly rounded umbilical margin. Ornament with fine growth lines, without ribs or nodes. Suture line with a narrow and very shallow external lobe and a much larger and deeper, broadly rounded lateral lobe. Etymology Named after the late Bahaeddin Hamdi (1935–2019), the promoter of palaeontology in Iran. Type material Holotype IRAN – East Azerbaijan • Ali Bashi 4; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 11; MB.C.32006. Paratypes IRAN – West Azerbaijan • 1 specimen; Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; MB.C.32007 • 1 specimen; same data as for preceding; 2011; Korn et al. leg.; MB.C.32008 • 1 specimen; same data as for preceding; 2013; Korn et al. leg.; MB.C.32009 • 2 specimens; same data as for preceding; 2018; Korn et al. leg.; MB.C.32010 to MB.C.32011. – East Azerbaijan • 1 specimen; Ali Bashi 4; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; MB.C.32012 • 1 specimen; same data as for preceding; 2010; Korn et al. leg.; MB.C.32013 • 1 specimen; same data as for preceding; 2011; Korn et al. leg.; MB.C.32014 • 1 specimen; Zal; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; MB.C.32015. Description Holotype MB.C.32006 is a phragmocone fragment with a whorl height of 30 mm (Fig. 11A) and allows for examination of the dorsal whorl area. The shape of the conch was reconstructed using this fragment; this results in a diameter of 80 mm. The whorl profile of the specimen is compressed (ww/wh = 0.80) and trapezoidal with a very weakly concave venter, subangular ventrolateral shoulders, flattened and convergent flanks, a rounded umbilical margin and a very shallow dorsal zone (Fig. 11B). The dorsal zone shows that the penultimate whorl also had a weakly concave venter. The complete suture line is exposed. It shows that the external lobe is very shallow and that the ventrolateral saddle is subangular. The lateral lobe is broadly rounded and continues, at the umbilical seam, into a very shallow internal Fig. 11. Permodomatoceras hamdii sp. nov., holotype MB.C.32006 (Ghaderi 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Ali Bashi 4. A. Lateral view. B. Whorl profile. C. Suture line at ww = 23.3 mm, wh = 27.6 mm. Scale bar units = mm. European Journal of Taxonomy 1018: 1–113 (2025) 20 lobe, in which a very low and rounded saddle is raised (Fig. 11C). The septa are closely spaced; there are about ten chambers on a quarter of a volution (SD ~ 9 degrees). Some of the other specimens, such as paratype MB.C.32015, which is not illustrated, show a transformation of the ventrolateral shoulder from a subangular to a tightly rounded shape in the adult stage. In this specimen the shape change takes place at about 28 mm whorl height. Remarks It is most likely that the specimens illustrated by Shimansky (1965b) and Teichert & Kummel (1973) under the name “Domatoceras hunicum” belong to this species. However, P. hunicum differs from the new species in having septa in much larger distances (about five septa per quarter volution) than P. hamdii sp. nov. (10 septa per quarter volution). Another difference is the rate on whorl overlap, which is rather great in P. hunicum (IZR ~ 0.15), while it is very low in P. hamdii (IZR ~ 0.05). The new species has a narrower whorl profile (ww/wh = 0.80) than the type species of the genus. However, as its conch shape with the almost rectangular, rather wide whorl profile clearly distinguishes it from the species of the genus Domatoceras, it is classified here as Permodomatoceras. Genus Fididomatoceras gen. nov. urn:lsid:zoobank.org:act:FE3F69BC-FA94-4E56-9253-D9583FCD3BB2 New genus A – Korn 2025: 39. Type species Fididomatoceras intracostatum gen. et sp. nov. Diagnosis Genus of the family Domatoceratidae with a small to moderately large, subinvolute conch; whorl profile lyriform, venter flat or concave and bordered by raised keels, umbilical margin narrowly rounded. Sculpture missing or with blunt ribs on the flanks in the juvenile stage. Suture line with narrow, rounded external lobe and broadly rounded lateral lobe. Etymology Combination of the Latin ‘fidis’ (noun, f.) = ‘lyre’ and Domatoceras; because of the lyriform whorl profile. Included species Transcaucasia (Shimansky 1965b; this paper): Fididomatoceras gracile (Shimansky, 1965) gen. et comb. nov., Wuchiapingian, Azerbaijan; Fididomatoceras intracostatum gen. et sp. nov., Wuchiapingian, NW Iran. Table 3. Conch dimensions (in mm) and ratios of Permodomatoceras hamdii sp. nov.; reconstructed dimensions and ratios in italics. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32006 80.0 24.4 30.5 31.0 29.0 0.31 0.80 0.39 2.46 0.05 MB.C.32009 – 30.6 35.3 – – – 0.87 – – – MB.C.32010 – 28.0 35.0 – – – 0.80 – – – MB.C.32015 – 29.5 33.3 – – – 0.89 – – – MB.C.32007 – 25.5 28.6 – – – 0.89 – – – MB.C.32013 – 21.8 25.4 – – – 0.86 – – – KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 21 Remarks The new genus differs from most other genera in the family Domatoceratidae by its narrow umbilicus (uw/dm = 0.25–0.30), which in the other genera is usually much wider (uw/dm = 0.35–0.40). The most important distinguishing feature, however, is the shape of the ventrolateral shoulder, which in the other genera is tightly rounded or simply subangular or angular, but in Fididomatoceras gen. nov. is accentuated by a shallow inflexion of the outer flank. The lyriform whorl profile in Fididomatoceras is also the main difference to the otherwise similar Late Carboniferous genus Stenodomatoceras. Fididomatoceras gracile (Shimansky, 1965) gen. et comb. nov. Fig. 12; Table 4 Domatoceras gracile Shimansky, 1965b: 160, pl. 16 fig. 1. Diagnosis Species of Fididomatoceras gen. nov. with thinly discoidal, subinvolute conch (ww/dm ~ 0.35; uw/dm ~ 0.25), weakly compressed whorl profile (ww/wh ~ 0.70) and extremely high coiling rate (WER ~ 3.05) at a conch diameter of 40–55 mm. Whorl profile inverted trapezoidal with convergent flanks; venter and flanks flattened, umbilical margin broadly rounded. Suture line with broadly rounded, moderately deep external lobe and slightly larger and deeper, broadly rounded lateral lobe. Type material Holotype AZERBAIJAN • Dorasham 1; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); illustrated by Shimansky (1965b: pl. 16 fig. 1); PIN 1572/211. Material examined IRAN – East Azerbaijan • 1 specimen; Ali Bashi N; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Korn et al. leg.; illustrated in Fig. 12; MB.C.32016. Fig. 12. Fididomatoceras gracile (Shimansky, 1965) gen. et comb. nov., specimen MB.C.32016 (Korn et al. 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Ali Bashi N. A. Lateral view of left side. B. Reconstruction of apertural view. C. Lateral view of right side. D. Suture line at dm = 58.0 mm, ww = 17.0 mm, wh = 21.0 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 22 Description Specimen MB.C.32016 is a fairly complete, but rather poorly preserved specimen with a conch diameter of 58 mm (Fig. 12A, C). On the right side it is heavily encrusted by a tabular coral colony. The conch is thinly discoidal and subinvolute (ww/dm = 0.35; uw/dm = 0.26) with a compressed whorl profile (ww/ wh = 0.70). The venter is weakly flattened and bordered by a subangular ventrolateral shoulder. The umbilical margin is rounded, from here the sinuous flanks converge to the venter (Fig. 12B). The suture line has a relatively large and deep, broadly rounded external lobe, a narrowly rounded ventrolateral saddle and a broadly rounded, shallow lateral lobe that occupies the entire flank (Fig. 12D). Remarks Shimansky (1965b) discussed the external similarity of Fididomatoceras gracile gen. et comb. nov. and the Late Carboniferous species Stenodomatoceras moorei (Miller, Dunbar & Condra, 1933). He stated that differences between these species mainly regard very different conch sizes and the much more involute conch of S. moorei. He thus regarded this as a case of homeomorphy. However, the size of the specimens can hardly be used to distinguish species or even genera. The holotype of F. gracile is only 40 mm in diameter and is probably a preadult specimen. The difference in umbilical width is a better separating criterion; the holotype of S. moorei has, at a conch diameter of 40 mm, a uw/dm ratio of 0.21, whereas this is 0.28 in the holotype of F. gracile. A hypothetical criterion for differentiation between Fididomatoceras gen. nov. and Stenodomatoceras could be the position of the siphuncle; this is close to the venter in S. moorei and also in S. kleihegei (Miller, Lane & Unklesbay, 1947). However, the position of the siphuncle in F. gracile gen. et comb. nov. is not known. Stenodomatoceras kleihegei and S. gardi (Murphy, 1970) possess a concave venter bordered by a slightly raised ventrolateral shoulder, which is narrowly rounded or subangular in F. gracile. Because of these differences, but mainly because of the large stratigraphic distance in occurrence of the three known Late Carboniferous North American species of Stenodomatoceras and F. gracile, we follow the interpretation of Shimansky (1965b) here and do not classify F. gracile in Stenodomatoceras. Instead, we place it in the new genus Fididomatoceras described here. Fididomatoceras gracile gen. et comb. nov. can be easily distinguished from most of the species of the family Domatoceratidae from Transcaucasia by the narrower umbilicus, the more widely embracing whorls and the higher coiling rate (WER > 3.00 in F. gracile, but usually 2.25–2.50 in the other species). Fididomatoceras gracile differs from F. intracostatum gen. et sp. nov. in the absence of ribs in the juvenile stage and in the less distinct ventrolateral shoulder, which is narrowly rounded in F. gracile but angular in F. intracostatum. Furthermore, F. gracile has a higher coiling rate (WER > 3.00) than F. intracostatum (WER < 2.75). Fididomatoceras intracostatum gen. et sp. nov. urn:lsid:zoobank.org:act:3DDD3943-57AC-4E12-9036-70812D1C1220 Fig. 13; Table 5 Diagnosis Species of Fididomatoceras gen. nov. with thinly discoidal, subinvolute conch (ww/dm ~ 0.40; uw/ dm ~ 0.27), weakly compressed whorl profile (ww/wh ~ 0.90) and extremely high coiling rate Table 4. Conch dimensions (in mm) and ratios of Fididomatoceras gracile Shimansky, 1965 gen. et comb. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32016 58.4 20.5 29.2 15.4 25.0 0.35 0.70 0.26 3.06 0.14 PIN 1572/211 40.0 15.0 20.5 10.0 17.0 0.38 0.73 0.25 3.02 0.17 KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 23 (WER ~ 2.55) at a conch diameter of 30 mm. Whorl profile inverted trapezoidal or lyriform with convergent flanks; venter flattened, flanks flattened or slightly concave in the outer area, umbilical margin narrowly rounded. Sculpture in the juvenile stage with blunt ribs on the flanks. Suture line with very narrow external lobe and slightly larger and deeper, broadly rounded lateral lobe. Etymology Combination of the Latin ‘intra’ (prepos.) = ‘inner’ and ‘costatum’ (adj., n.) = ‘ribbed’; because of the juvenile sculpture. Type material Holotype IRAN – East Azerbaijan • Ali Bashi N; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Korn et al. leg.; illustrated in Fig. 13A–B; MB.C.32017. Paratype IRAN – West Azerbaijan • 1 specimen; Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 13C–E; MB.C.32018. Description Holotype MB.C.32017 is the better preserved of the two comparatively small specimens (Fig. 13A). It has a conch diameter of 32 mm and is thinly discoidal and subinvolute (ww/dm = 0.42; uw/dm = 0.26). The coiling rate is extremely high (WER = 2.61) and the imprint zone is small. The whorl profile is weakly compressed (ww/wh = 0.89) and shows a narrowly rounded umbilical margin and a steep, slightly flattened umbilical wall. The conch is widest near the umbilical margin; from here the flanks slowly converge towards the angular ventrolateral shoulder, which is preserved as a weakly elevated ridge. The venter becomes flat only in the last half of the volution, beginning at a conch diameter of about 22 mm. Before this, the venter is broadly rounded (Fig. 13B). Shell remains are visible on large areas of the specimen, they show periodically strengthened growth lines extending with a broad arch in backward direction across the flanks and form a deep, angular ventral sinus. Two thirds of the last volution belong to this stage, while the previous ontogenetic stage before possesses shallow, backwardly directed ribs on the flanks. Fig. 13. Fididomatoceras intracostatum gen. et sp. nov. A. Holotype MB.C.32017 (Korn et al. 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Ali Bashi N, lateral and apertural views. B. The same specimen, reconstruction of apertural view. C. Paratype MB.C.32018 (Ghaderi 2018 Coll.) from Aras Valley, lateral and apertural views. D. The same specimen, reconstruction of apertural view. E. The same specimen; suture line at ww = 8.4 mm, wh = 7.0 mm. Scale bar units = mm. European Journal of Taxonomy 1018: 1–113 (2025) 24 Paratype MB.C.32018 has a conch diameter of 31 mm (Fig. 13C). It is thinly discoidal and subinvolute (ww/dm = 0.39; uw/dm = 0.30) with a compressed whorl profile (ww/wh = 0.87). The venter is rounded up to a conch diameter of 27 mm and becomes flattened thereafter (Fig. 13D). This means that it reaches the stage with pronounced ventrolateral shoulders and the applanate venter at a larger conch diameter than the holotype. The suture line shows a very shallow, broadly rounded external lobe and a slightly deeper, rounded lateral lobe (Fig. 13E). Remarks Fididomatoceras intracostatum gen. et sp. nov. can hardly be confused with another nautilid species of Transcaucasia because of its very characteristic morphology. Fididomatoceras intracostatum differs from F. gracile gen. et comb. nov. in the presence of ribs in the juvenile stage and in the more distinct ventrolateral shoulder, which is angular in F. intracostatum but narrowly rounded in F. gracile. Furthermore, F. intracostatum has a lower coiling rate (WER < 2.75) than F. gracile (WER > 3.00). New family Korn & Hairapetian (in press) Diagnosis Family of the superfamily Grypoceratoidea with a usually discoidal, subinvolute conch. Whorl profile in the adult stage weakly compressed or weakly depressed; flanks and venter usually separated by a distinct ventrolateral shoulder, venter more or less concave. Umbilical margin usually subangular or angular, rarely rounded; umbilical wall steep, often flattened. Ornament usually consisting of fine growth lines. Septum simple in shape, concavely domed; suture line depending on whorl profile with shallow to V-shaped external lobe and shallow lateral lobe (from Korn & Hairapetian in press: 14). Included genera Pseudotitanoceras Shimansky, 1965 (Permian); new genus A to be described by Korn & Hairapetian (in press) (Permian); new genus B to be described by Korn & Hairapetian (in press) (Permian); Azarinautilus gen. nov. (Permian). Remarks A detailed discussion of the new family will be given by Korn & Hairapetian (in press). Genus Azarinautilus gen. nov. urn:lsid:zoobank.org:act:CD71EEC0-54D7-47EC-A234-F505CEDED059 New genus B – Korn 2025: 43. Type species Azarinautilus nahidae gen. et sp. nov. Diagnosis Genus of the new family Korn & Hairapetian (in press) with a rather small, subinvolute or subevolute conch; whorl profile lyriform, venter moderately to deeply concave and bordered by raised keels, Table 5. Conch dimensions (in mm) and ratios of Fididomatoceras intracostatum gen. et sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32017 32.0 13.3 15.0 8.4 12.2 0.42 0.89 0.26 2.61 0.19 MB.C.32018 30.3 11.7 13.5 9.0 11.2 0.39 0.87 0.30 2.52 0.17 KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 25 Genus Pseudotitanoceras Shimansky, 1965 Type species Nautilus armeniacus Abich, 1878; original designation. Included species Nautilus armeniacus Abich, 1878, Wuchiapingian, Azerbaijan. Remarks The type species of the genus is rather poorly known. Although there has been a brief revision by Shimansky (1965b) on the basis of new material, there is still no clear differentiation from other species. Shimansky (1965b) discussed the variation in the sculpture of his specimens; however, this may be due to the possibility that he also included specimens of the new genus A to be described by Korn & Hairapetian (in press). Pseudotitanoceras armeniacum (Abich, 1878) Nautilus armeniacus Abich, 1878: 24, pl. 2 fig. 5. Pseudotitanoceras armeniacum – Shimansky 1965b: 162, pl. 16 figs 5–6. Type material Holotype AZERBAIJAN • Dorasham 1; Araxoceras Beds (early Wuchiapingian); illustrated by Abich (1878: pl. 2 fig. 5); LGI 14/99. Remarks “Nautilus armeniacus, nov. form.” was described and illustrated by Abich (1878: pl. 2 fig. 5). It is a phragmocone fragment with a whorl height of about 38 mm. It is deformed but shows some features of the conch shape and sculpture. According to Abich’s description, the flanks are slightly concave and the venter is more clearly concave; they are separated by a narrowly rounded ventrolateral shoulder. The ventrolateral shoulder bears closely spaced nodes, which have the same width as the interspaces and also correspond approximately to the distances between the septa. The suture line shows broadly rounded lobes on the flanks and venter. Suborder Tainoceratina Shimansky, 1957 Diagnosis Suborder of the order Nautilida, in which a ventrolateral shoulder and an umbilical margin are formed early in ontogeny in the advanced species. Conch usually discoidal, subinvolute to evolute. Juvenile whorl profile depressed oval or circular. Adult whorl profile depressed oval or reniform in the early species, showing numerous modifications during evolution (inverted trapezoidal, trapezoidal or polygonal whorl profiles or with ventral depression). Dorsal whorl zone always present, but usually very small. Juvenile sculpture with radial ribs on the flank; adult sculpture with radial ribs on the flank, ventrolateral nodes or several rows of nodes in derived species. Septa simply domed; with dorsal inflexion in advanced species. Suture line depending on the whorl profile, with shallow lobes and low saddles (from Korn 2025). European Journal of Taxonomy 1018: 1–113 (2025) 32 Included superfamilies Tainoceratoidea Hyatt, 1883 (Carboniferous to Triassic); Pleuronautiloidea Hyatt, 1900 (Carboniferous to Triassic). Remarks A detailed discussion of the suborder Tainoceratina has been given by Korn (2025). Superfamily Pleuronautiloidea Hyatt, 1900 Diagnosis Superfamily of the suborder Tainoceratina with a discoidal, subinvolute to subevolute conch. Whorl profile in early species subquadrate with distinct ventrolateral shoulder and distinct umbilical margin. Derived species show a variation of modifications including trapezoidal, inverted trapezoidal or hexagonal whorl profiles with a less angular ventrolateral shoulder and umbilical margin. Whorl overlap is always very small. Sculpture in early species with transverse ribs and ventrolateral nodes, in derived species often with ribs and several rows of nodes. Septa simply domed, in derived species with dorsal inflexion that produces an annular process. Suture line with broadly rounded lateral lobe and shallow lobe or low saddle on the venter (from Korn 2025). Included families Pleuronautilidae Hyatt, 1900 (Permian to Triassic); Gzheloceratidae Ruzhencev & Shimansky, 1954 (Carboniferous to Permian); Mosquoceratidae Ruzhencev & Shimansky, 1954 (Carboniferous to Permian); Aktubonautilidae Ruzhencev & Shimansky, 1954 (Permian); Rhiphaeoceratidae Ruzhencev & Shimansky, 1954 (Permian); Metacoceratidae Korn, 2025 (Carboniferous to Permian); Foordiceratidae Korn, 2025 (Permian). Remarks A detailed discussion of superfamily Pleuronautiloidea has been given by Korn (2025). Family Metacoceratidae Korn, 2025 Diagnosis Family of the superfamily Pleuronautiloidea with an equidimensional or more commonly weakly depressed, trapezoidal to inverted trapezoidal whorl profile. Venter usually flattened, but ranging from slightly convex to slightly concave. Ventrolateral shoulder often prominent, ranging from broadly rounded to subangular. Flanks weakly convergent, parallel or weakly divergent, usually flattened and ranging from weakly convex to weakly concave. Umbilical margin usually pronounced, usually subangular in the intermediate growth stage. Sculpture with ventrolateral conical nodes, often with dorsolateral nodes and low ribs on the flank. Suture line with shallow lobes and low saddles. Internal lobe very shallow, without annular process (from Korn 2025). Included genera Metacoceras Hyatt, 1883 (Carboniferous to Triassic); Mojsvaroceras Hyatt, 1883 (Triassic); Huanghoceras Yin, 1933 (Permian); ? Shansinautilus Yabe & Mabuti, 1935 (Permian;); Cooperoceras Miller, 1945 (Permian); Epimetacoceras Librovitch, 1946 (Carboniferous) (nomen nudum); Pseudofoordiceras Ruzhencev & Shimansky, 1954 (Permian); Pseudotemnocheilus Ruzhencev & Shimansky, 1954 (Permian); Tanchiashanites Zhao, 1954 (Permian); Mahoningoceras Murphy, KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 33 1974 (Carboniferous); Lichuanoceras Xu, 1977 (Permian); Sinotitanoceras Pan, 1983 (Permian); Anthodiscoceras Qin, 1986 (Permian); Serometacoceras gen. nov. (Permian). Remarks A detailed account of the research history of Metacoceras and genera with similar morphology has been given by Korn (2025). Therefore, only the differences between the new genus Serometacoceras gen. nov. and Metacoceras will be discussed here. Genus Serometacoceras gen. nov. urn:lsid:zoobank.org:act:28DA9B4A-3B7E-421E-A054-779F73B20EA9 New genus C – Korn 2025: 50. Type species Pleuronautilus Verae von Arthaber, 1900. Diagnosis Genus of the family Metacoceratidae with a subinvolute or subevolute conch; whorl profile equidimensional or more or less strongly depressed, usually trapezoidal with weakly divergent flanks. Venter usually weakly convex or flattened; ventrolateral shoulder narrowly or broadly rounded. Umbilical margin pronounced and subangular in the intermediate growth stage, rounded in the adult stage. Sculpture with conical nodes on the ventrolateral shoulder or on the umbilical margin or both, sometimes connected by low ribs on the flank. Suture line with shallow external lobe or very low external saddle and broadly rounded lateral lobe; without annular process. Siphuncle small with subcentral position ventrad of septum centre. Etymology From the Latin ‘serus’ (adj., net.) = ‘late’; because of the high stratigraphic position and the similarity to Metacoceras. Included species Transcaucasia and NW Iran (Abich 1878; von Arthaber 1900; Shimansky 1965b; Kotlyar et al. 1989; this paper): Nautilus dorso armatus Abich, 1878, Wuchiapingian, Azerbaijan; Nautilus tubercularis Abich, 1878, Wuchiapingian, Azerbaijan; Nautilus incertus Abich, 1878, Wuchiapingian, Azerbaijan; Nautilus Verae von Arthaber, 1900, Wuchiapingian, Azerbaijan; Metacoceras dorashamense Shimansky, 1965, Wuchiapingian, Azerbaijan; Pleuronautilus dzhulfensis Shimansky, 1965, Wuchiapingian, Azerbaijan [synonym of Serometacoceras verae gen. et comb. nov.]; Pleuronautilus costalis Shimansky, 1965, Wuchiapingian, Armenia; Pleuronautilus dzhagadzurensis Zakharov in Kotlyar et al., 1989, Capitanian, Azerbaijan; Serometacoceras cingulum gen. et sp. nov., Wuchiapingian, NW Iran; Serometacoceras inflatum gen. et sp. nov., Wuchiapingian, NW Iran; Serometacoceras parvituberculatum gen. et sp. nov., Wuchiapingian, NW Iran; Serometacoceras arasense gen. et sp. nov., Changhsingian, NW Iran. Central Iran (Korn & Hairapetian in press): new species I to be described by Korn & Hairapetian (in press), Wuchiapingian. Pakistan (Waagen 1879; Reed 1931, 1944): Nautilus latissimus Waagen, 1879, Wuchiapingian, Salt Range; Gyroceras Medlicottianum Waagen, 1879, Wuchiapingian, Salt Range; Metacoceras warchense Reed, 1931, Wuchiapingian, Salt Range; Metacoceras chittidilense Reed, 1944, Wuchiapingian, Salt Range; Parametacoceras venustum Reed, 1944, Wuchiapingian, Salt Range. European Journal of Taxonomy 1018: 1–113 (2025) 34 South China (Xu 1977; Zheng 1984; Ma 1997): Metacoceras hunanense Xu, 1977, Changhsingian, Hunan; Pleuronautilus changxingensis Zhao, Liang & Zheng, 1978, Changhsingian, Zhejiang; Pleuronautilus zhongyingensis Zheng, 1984, Changhsingian, Guizhou; Pleuronautilus magnus Zheng, 1984, Changhsingian, Guizhou; Pleuronautilus anfuensis Ma, 1997, Wuchiapingian, Jiangxi; Pleuronautilus curvatus Ma, 1997, Wuchiapingian, Jiangxi; Pleuronautilus robustus Ma, 1997, Wuchiapingian, Jiangxi. Remarks The Transcaucasian material appears to represent a morphocline ranging from forms with a relatively simple sculpture consisting only of ventrolateral nodes to forms with ribs and a few rows of nodes on the flank. All of these forms have previously been assigned to the genera Metacoceras and Pleuronautilus Mojsisovics, 1882 (Kummel 1953; Shimansky 1965b; Teichert & Kummel 1973). However, Shimansky (1965b: 158) already noted some uncertainties regarding the exact delimitation of the two genera on the basis of the specimens from Dzhulfa. A division of the morphocline represented in the material from Julfa into the two genera Metacoceras and Pleuronautilus would have consequences for the phylogenetic reconstruction of the suborder Tainoceratina. Species previously assigned to Pleuronautilus are already known from Early Permian strata, such as the Leonard Formation of Texas. These were placed in the genus Foordiceras Hyatt, 1893 by Miller & Youngquist (1949) and in Pseudofoordiceras by Ruzhencev & Shimansky (1954). Kummel (1953: 12) discussed at length the phylogenetic relationships within the family Tainoceratidae (as he understood it) and concluded that these species belong to Pleuronautilus, a view that was supported by Shimansky (1967). However, this would mean that the origin of the genus Pleuronautilus was in the Early Permian or even earlier. Assigning parts of the Transcaucasian morphocline to Pleuronautilus would mean that this genus is polyphyletic or that very similar morphologies occur in the genera Metacoceras and Pleuronautilus. Dzik (1984: 161) already assumed that the genus Pleuronautilus, as previously used by many authors, is a polyphyletic taxon containing several evolutionary lineages. In contrast to previous authors (Kummel 1953; Ruzhencev & Shimansky 1954), who proposed a relatively simple evolutionary scenario starting with the main genus Metacoceras, from which most of the other of the tainoceratid genera branched off, Dzik (1984, p. 162, fig. 62) proposed a much more complex picture with a number of independent evolutionary lineages. In this phylogenetic reconstruction, Metacoceras does not play a central role and is not considered to be ancestral to genera such as Tainoceras Hyatt, 1883 and Pleuronautilus. Also, the Late Permian species known from Transcaucasia, which Shimansky (1965b) and Teichert & Kummel (1973) referred to as Metacoceras and Pleuronautilus, were thought to have evolved independently of Metacoceras. In the following, we place the morphocline with “Nautilus dorso armatus” and “Pleuronautilus verae” completely in the new genus Serometacoceras gen. nov. Some representatives of these Late Permian forms that have previously been placed in Pleuronautilus actually have a sculpture very reminiscent of Pleuronautilus, but they lack an annular process. Such forms are described by Korn & Hairapetian (in press) as belonging to the new genus C to be described by Korn & Hairapetian (in press). Serometacoceras gen. nov. differs from Metacoceras in the shape of the whorl profile, which in Serometacoceras is depressed and usually trapezoidal with weakly divergent flanks, while Metacoceras normally has converging flanks. A further difference lies in the formation of the sculpture, which is composed of coarser ribs in Serometacoceras. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 35 Serometacoceras dorsoarmatum (Abich, 1878) gen. et comb. nov. Figs 3C, 17; Table 9 Nautilus dorso armatus Abich, 1878: 20, pl. 4 fig. 1. Pleuronautilus dorso-armatus – von Arthaber 1900: 215. Pleuronautilus (Pleuronautilus) dorso-armatus – Kummel 1953: 36. Metacoceras dorsoarmatum – Shimansky 1965a: 41, pl. 14 fig. 5. — Teichert & Kummel 1973: 417, pl. 3 figs. 5–6. Diagnosis Species of Serometacoceras gen. nov. with thickly discoidal, subevolute conch (ww/dm = 0.45–0.50; uw/dm = 0.40–0.45), weakly depressed whorl profile (ww/wh = 1.15–1.40) and very high coiling rate (WER = 2.30–2.50) at a conch diameter of 50 mm. Whorl profile weakly trapezoidal with gently divergent flanks; venter and flanks flattened. Sculpture with 10–12 low ventrolateral nodes per volution; the nodes show a short extension toward the midflank. Suture line with a broad and shallow external lobe and a slightly deeper, broadly rounded lateral lobe. Material examined IRAN – East Azerbaijan • 1 specimen; Ali Bashi 4; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 17A–C; MB.C.32026. – West Azerbaijan • 1 specimen; Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 17D–F; MB.C.32027 • 1 specimen; same data as for preceding; 2012; Korn et al. leg.; illustrated in Fig. 17G; MB.C.32028. Description Specimen MB.C.32026 is the largest specimen available; it is a somewhat corroded fragment of an internal mould with a whorl height of 38 mm, corresponding to a conch diameter of about 115 mm (Fig. 17A). Only one third of the whorl is preserved, showing remains of the last three phragmocone chambers and a part of the body chamber. The whorl profile is trapezoidal and slightly depressed (ww/ wh = 1.19) with a broadly rounded venter and a prominent, narrowly rounded ventrolateral shoulder. The flattened flanks are weakly divergent and the umbilical margin is broadly rounded (Fig. 17B). The sculpture consists of very shallow ribs beginning on the inner flank and becoming coarser towards the outer flank where they terminate in transversely elongated, low and blunt ventrolateral nodes. They become much weaker in the last preserved part of the body chamber. It appears that these nodes do not coincide between the two sides of the conch, but rather alternate in position. The suture line of the specimen shows a very broad and flat external lobe, a broadly rounded ventrolateral saddle and a flat, broadly rounded lateral lobe (Fig. 17C). Specimen MB.C.32027 (Fig. 17D) is an internal mould fragment of a specimen with a conch diameter of about 48 mm, consisting of a quarter of a whorl with the last phragmocone chambers and part of the body chamber. It has a subquadrate, weakly depressed whorl profile (ww/wh = 1.17) with a flatly rounded venter, a narrowly rounded ventrolateral shoulder, slightly concave and weakly divergent flanks and a raised and thus rather pronounced, but rounded umbilical margin (Fig. 17E). The ventrolateral shoulder bears short radially elongated nodes that extend only a short distance towards the flank, were they are visible only as very low ridges. The umbilical margin bears barely visible, very small tubercles. The suture line has a very shallow external lobe and a broadly rounded lateral lobe (Fig. 17F). The septa are separated by an average of about 13 degrees. European Journal of Taxonomy 1018: 1–113 (2025) 36 Specimen MB.C.32028 is externally corroded and was sectioned for the study of the inner whorls; it is slightly deformed and was digitally re-deformed for the illustration (Fig. 17G). The cross section shows some ontogenetic changes in the shape of the whorls, starting with a circular profile in the early ontogenetic stage, followed by an inverted trapezoidal shape at a conch diameter of 11.5 mm. Half a volution later, at 19 mm diameter, the whorl profile is rounded-hexagonal with a pronounced, slightly raised umbilical margin and parallel flanks. In the course of half a volution from a conch diameter of 30 to 45 mm, the flanks become clearly divergent and slightly concave. At 39 mm diameter, the section shows a pronounced ventrolateral node extending about 3 mm beyond the ventrolateral shoulder. Finally, Fig. 17. Serometacoceras dorsoarmatum (Abich, 1878) gen. et comb. nov. from the Araxoceras Beds of the Julfa Formation. A. Specimen MB.C.32026 (Ghaderi 2018 Coll.) from Ali Bashi 4, lateral view. B. The same specimen, whorl profile. C. The same specimen, suture line at ww = 45.0 mm, wh = 38.5 mm. D. Specimen MB.C.32027 (Ghaderi 2018 Coll.) from Aras Valley, lateral view. E. The same specimen, whorl profile. F. The same specimen, suture line at ww = 23.5 mm, wh = 18.5 mm. G. Specimen MB.C.32028 (Korn et al. 2012 Coll.) from Aras Valley, cross section and reconstruction of apertural view. Scale bar units = 1 mm. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 37 the whorl profile of the last volution shows a broadly rounded umbilical margin and flanks that merge continuously into the umbilical wall. Only minor ontogenetic changes in the cardinal conch parameters can be detected, but it must be taken into account that the ww/dm and ww/wh ratios can be influenced by the position of the cross section relative to the ribs. Whether the section hits a node or interspace is critical to the shape of the whorl profile. However, it can be seen clearly that the uw/dm ratio slowly increases from a value of 0.33 at a conch diameter of 11.5 mm to 0.42 at 68 mm diameter. Remarks Abich (1878: pl. 4 fig. 1) illustrated a specimen with a diameter of 53 mm under the name “Nautilus dorso armatus, nov. form.”; this fragment allows a fairly accurate description of the morphology of the conch and the sculpture (Fig. 3C). The conch is subevolute (uw/dm ~ 0.40) with a weakly depressed whorl profile (ww/wh ~ 1.25). The venter appears to be flattened and the flanks are bordered by a rounded ventrolateral shoulder and a rounded but distinct umbilical margin. The sculpture consists of five laterally directed nodes on half a whorl, which are about half as wide as their interspaces. They are somewhat elongated towards the umbilicus and extend almost to the middle of the flank. The penultimate whorl bears about eight shallow radial riblets on the flank on half a volution. The suture line extends with shallow and rounded lobes across venter, flanks and umbilical wall. Shimansky (1965b: pl. 14 fig. 5) showed a more complete specimen with a conch diameter of 72 mm; this agrees well with Abich’s original specimen. The close resemblance of these two specimens to the newly collected material from Iran allows a fairly good identification of the new specimens. Serometacoceras dorsoarmatum gen. et comb. nov. is very similar to S. dorashamense gen. et comb. nov., but differs in having considerably shorter ribs, confined to the outer flank. In contrast to S. dorashamense, S. dorsoarmatum has no umbilical nodes. Another, albeit small, difference lies in the width of the umbilicus. In S. dorsoarmatum, the uw/dm ratio is greater than 0.40 and in S. dorashamense only around 0.37. Serometacoceras dorashamense (Shimansky, 1965) gen. et comb. nov. Fig. 18; Table 10 Metacoceras dorashamense Shimansky, 1965b: 157, pl. 14 fig. 3. Pleuronautilus sp. indet. 1 – Teichert & Kummel 1973: 418, pl. 1 figs 3–4. Pleuronautilus sp. – Gliwa et al. 2020: text-fig. 17b. non Metacoceras dorashamense – Teichert & Kummel 1973: 416, pl. 4 figs 5–6. Table 9. Conch dimensions (in mm) and ratios of Serometacoceras dorsoarmatum (Abich, 1878) gen. et comb. nov.; reconstructed dimensions and ratios in italics. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32026 115.0 45.4 39.0 47.0 37.0 0.39 1.16 0.41 2.17 0.05 MB.C.32027 48.2 22.8 19.5 19.4 18.0 0.47 1.17 0.40 2.55 0.08 MB.C.32028 67.9 29.8 23.6 28.8 22.7 0.44 1.26 0.42 2.26 0.03 MB.C.32028 45.2 22.6 15.6 18.4 15.3 0.50 1.45 0.41 2.29 0.01 MB.C.32028 29.8 15.3 11.2 11.0 10.8 0.51 1.37 0.37 2.45 0.04 MB.C.32028 19.1 9.4 7.7 6.4 7.4 0.49 1.23 0.34 2.66 0.04 MB.C.32028 11.7 5.9 5.0 3.8 5.0 0.51 1.18 0.33 3.06 0.00 European Journal of Taxonomy 1018: 1–113 (2025) 38 Diagnosis Species of Serometacoceras gen. nov. with thickly discoidal, subevolute conch (ww/dm = 0.45–0.50; uw/dm = 0.35–0.40), weakly depressed whorl profile (ww/wh = 1.20–1.30) and very high coiling rate (WER = 2.30–2.50) at a conch diameter of 50 mm. Whorl profile nearly rectangular, usually with gently divergent flanks; venter and flanks flattened. Sculpture with 10–12 low ventrolateral nodes per volution; the nodes are connected by slightly curved ribs with weak nodes on the umbilical margin. Suture line with a broad and shallow external lobe and a usually slightly deeper, broadly rounded lateral lobe. Type material Holotype AZERBAIJAN • Dorasham; Araxoceras Beds (early Wuchiapingian); illustrated by Shimansky (1965b: pl. 14 fig. 3); PIN 1572/246. Material examined IRAN – West Azerbaijan • 1 specimen; Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2013; Korn et al. leg.; illustrated in Fig. 18A–C; MB.C.29347 • 1 specimen; same data as for preceding; 2018; Korn et al. leg.; illustrated in Fig. 18D–F; MB.C.32029 • 1 specimen; same data as for preceding; 2018; Ghaderi leg.; illustrated in Fig. 18G–I; MB.C.32030 • 1 specimen; same data as for preceding; 2018; Ghaderi leg.; illustrated in Fig. 18J–L; MB.C.32031 • 5 specimens; same data as for preceding; 2018; Ghaderi leg.; MB.C.32032 to MB.C.32036 • 1 specimen; same data as for preceding; 2011; Korn et al. leg.; MB.C.32037 • 2 specimens; same data as for preceding; Korn et al. 2013, 2018 Coll.; MB.C.32038, MB.C.32039. – East Azerbaijan • 2 specimens; Ali Bashi 4; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; MB.C.32040, MB.C.32041 • 1 specimen; Ali Bashi main valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; MB.C.32042 • 1 specimen; Zal; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; MB.C.32043. Description Specimen MB.C.29347 is a 120-degree long segment consisting of part of the body chamber and two chambers of the phragmocone. The total diameter can be estimated at approximately 60 mm (Fig. 18B). The specimen has a subquadrate whorl profile with a flattened venter, a rounded ventrolateral shoulder, slightly divergent and weakly concave flanks and a rounded umbilical margin (Fig. 18A). The sculpture consists of coarse ribs that deviate slightly from the radial direction towards the aperture. They emerge on the inner flank near the umbilical margin with a slightly tubercular thickening, become more prominent in the middle of the flank and, after tapering further, end close to the ventrolateral shoulder in a blunt and elongated tubercle. Ribs and nodes are asymmetrically arranged and not arranged in exact correspondence on both sides of the conch. Specimen MB.C.32029 is a phragmocone segment of 120 degrees length (Fig. 18E). Its maximum whorl height is 20 mm, which corresponds to a conch diameter of about 50 mm. The whorl profile is weakly depressed and subquadrate (ww/wh = 1.30) and almost widest at the rounded umbilical margin, from where the flanks very slowly diverge towards the rounded ventrolateral shoulder (Fig. 18D). The venter is flattened and possesses a very shallow concave depression at the beginning of the whorl segment. The sculpture shows five prominent ribs on the segment. These ribs originate at the umbilical margin and extend radially across the flanks; in the outer flank area they strengthen significantly to form large and rounded nodes. The suture line has a rather small and shallow external lobe and a large rounded lateral lobe with asymmetric shape (the ventral side is much longer than the dorsal) and a very shallow, small lobe on the umbilical wall (Fig. 18F). KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 39 Fig. 18. Serometacoceras dorashamense (Shimansky, 1965) gen. et comb. nov. from the Araxoceras Beds of the Julfa Formation. A. Specimen MB.C.29347 (Korn et al. 2013 Coll.) from Aras Valley, reconstruction of apertural view. B. The same specimen, lateral and ventral views. C. The same specimen, suture line at ww = 19.8 mm, wh = 20.4 mm. D. Specimen MB.C.32029 (Korn et al. 2018 Coll.) from Aras Valley, whorl profile. E. The same specimen; lateral and ventral views. F. The same specimen, suture line at ww = 20.8 mm, wh = 15.8 mm. G. Specimen MB.C.32030 (Ghaderi 2018 Coll.) from Aras Valley, ventral and lateral views. H. The same specimen, whorl profile. I. The same specimen, suture line at ww = 21.5 mm, wh = 19.5 mm. J. Specimen MB.C.32031 (Ghaderi 2018 Coll.) from Aras Valley, lateral view. K. The same specimen, whorl profile. L. The same specimen; suture line at ww = 24.2 mm, wh = 18.9 mm. Scale bar units = 1 mm. Table 10. Conch dimensions (in mm) and ratios of Serometacoceras dorashamense Shimansky, 1965 gen. et comb. nov.; reconstructed dimensions and ratios in italics. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.29347 60.0 24.2 21.5 19.0 20.5 0.40 1.13 0.32 2.31 0.05 MB.C.32031 57.1 26.4 22.2 21.1 20.5 0.46 1.19 0.37 2.44 0.08 MB.C.32030 54.3 27.4 21.2 19.8 19.2 0.50 1.29 0.36 2.39 0.09 MB.C.32029 48.7 23.6 18.2 18.0 17.0 0.48 1.30 0.37 2.36 0.07 European Journal of Taxonomy 1018: 1–113 (2025) 40 The fragmentary specimen MB.C.32030 (Fig. 18G; 21 mm whorl height) has a similar shape as specimen MB.C.32029, but is less depressed (ww/wh = 1.19). The ribs are not as coarse as in the other specimens and the suture line possesses a deeper external lobe (Fig. 18I). The septa are densely arranged at intervals averaging about 10 degrees only. Specimen MB.C.32031 (Fig. 18J) is a fragment with 22 mm whorl height and possesses a subquadrate whorl profile (ww/wh = 1.19) with weakly divergent flanks (Fig. 18K). Its sculpture consists of coarse and sharp ribs and the suture line shows a comparatively narrow and deep external lobe (Fig. 18L). The septa are spaced at intervals averaging about 15 degrees. Remarks Serometacoceras dorashamense gen. et comb. nov. was established by Shimansky (1965b) mainly on the basis of a rather small holotype with a conch diameter of only 35 mm. The type specimen still shows some early ontogenetic features, such as the distinctly angular umbilical margin and the rather coarse ribs. Although the new material from Iran only consists of fragments, their juvenile morphology can also be seen in the inner whorls of several of the larger specimens. Therefore, an assignment of this material to S. dorashamense is fairly certain. The larger specimens from Iran show weakening of the ribs and nodes. Serometacoceras dorashamense gen. et comb. nov. differs from S. dorsoarmatum gen. et comb. nov. in possessing rather coarse ribs on the flanks and small tubercles around the umbilicus. The umbilicus is somewhat narrower in S. dorashamense (uw/dm = 0.35–0.40 when compared to 0.40–0.45 in S. dorsoarmatum). Another species with similar morphology is S. verae gen. et comb. nov. but this differs from S. dorashamense gen. et comb. nov. in the more clearly developed umbilical nodes and the occasional presence of an additional row of nodes in the midflank region. A further distinguishing feature is the shape of the venter; in S. dorashamense it is flattened and in S. verae broadly rounded. Serometacoceras verae (von Arthaber, 1900) gen. et comb. nov. Figs 19–20; Table 11 Pleuronautilus Verae von Arthaber, 1900: 216, pl. 18 fig. 4. Pleuronautilus verae – Shimansky 1965a: 41. Pleuronautilus (Pleuronautilus) verae – Kummel 1953: 36. Pleuronautilus dzhulfensis Shimansky, 1965b: 158, pl. 15 figs 5–6. Nautilus Pichleri – Abich 1878: 21, pl. 4 fig. 2. Pleuronautilus sp. indet. 2 – Teichert & Kummel 1973: 418, pl. 4 figs 3–4. Diagnosis Species of Serometacoceras gen. nov. with thickly discoidal, subevolute conch (ww/dm ~ 0.50; uw/dm ~ 0.35), weakly depressed whorl profile (ww/wh ~ 1.25) and very high coiling rate (WER = 2.40–2.50) at a conch diameter of 50 mm. Whorl profile nearly rectangular, usually with gently convergent flanks; venter broadly convex, flanks flattened. Sculpture with about 15 low ventrolateral nodes per volution; the nodes are connected by slightly curved ribs with weak nodes on the umbilical margin, sometimes with an additional row of nodes on the midflank. Suture line nearly straight on the venter and with a broadly rounded lateral lobe. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 41 Type material Holotype IRAN – East Azerbaijan • Zal; Vedioceras Beds of the Julfa Formation (late Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 23; MB.C.32052. Description Holotype MB.C.32052 is a rather poorly preserved specimen with a conch diameter of 38 mm (Fig. 23A). It is thinly pachyconic (ww/dm = 0.70) and subevolute (uw/dm = 0.34) with a nearly rectangular, moderately depressed whorl profile (ww/wh = 1.73) and a very high coiling rate (WER = 2.40). The whorls are widest at the umbilical margin, from where the weakly convex umbilical wall approaches the umbilical seam. The flanks converge slowly towards the pronounced, narrowly rounded ventrolateral shoulders; the venter is broadly arched (Fig. 23B). The main element of the sculpture consists of delicate lateral ribs ending in a series of small tubercles on the ventrolateral shoulder. The suture line is visible only on the flanks and the umbilical wall, both of which have very shallow, broadly rounded lobes. Remarks Serometacoceras parvituberculatum gen. et sp. nov. differs from the other species of the genus in the very small and more numerous ventrolateral tubercles. Serometacoceras arasense gen. et sp. nov. urn:lsid:zoobank.org:act:05175D5D-1AC6-4527-AEF5-57CDC0E9EDC3 Fig. 24; Table 14 Pleuronautilus sp. – Gliwa et al. 2020: text-fig. 17d. Diagnosis Species of Serometacoceras gen. nov. with thinly discoidal, subinvolute conch (ww/dm ~ 0.45; uw/dm ~ 0.28), nearly quadrate whorl profile (ww/wh ~ 0.90) and extremely high coiling rate (WER ~ 2.70) at a conch diameter of 80 mm. Whorl profile flattened, parallel flanks; venter broadly rounded, flanks slightly flattened, umbilical margin subangular. Sculpture with about 15 short lateral plications per volution. Etymology Named after the type locality at the Aras River (West Azerbaijan, Iran). Type material Holotype IRAN – West Azerbaijan • Aras Valley; Zal Member of the Ali Bashi Formation (9.50 m below top) (early Changhsingian); 2011; Korn et al. leg.; illustrated in Fig. 24; MB.C.29349. Description Holotype MB.C.29349 is rather complete and has a conch diameter of 82 mm (Fig. 24B). It is preserved with adherent shell material but does not show the suture line. The conch is thinly discoidal and Table 13. Conch dimensions (in mm) and ratios of the holotype of Serometacoceras parvituberculatum gen. et sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32052 38.2 26.7 15.4 13.0 13.6 0.70 1.73 0.34 2.41 0.12 European Journal of Taxonomy 1018: 1–113 (2025) 48 subinvolute (ww/dm ~ 0.43; uw/dm = 0.28); the whorl profile is slightly compressed and subquadrate (ww/wh = 0.92) with flattened, parallel flanks, a pronounced ventrolateral shoulder and a broadly rounded venter (Fig. 24A). The umbilical margin is subangular in the last half of a volution with an obliquely oriented umbilical wall. In contrast, the penultimate volution (up to about 30 mm dm) has a very pronounced umbilical margin and an almost vertical umbilical wall. The sculpture of the last volution is dominated by weakly protracted radial plications. They begin at the umbilical margin, where they bear small tubercles, and gain in strength across the flanks. They terminate at the ventrolateral shoulder where they are coarsest and bear another row of tubercles. The umbilical opening allows the study of the sculpture in the preceding whorl, in which the ribs are much coarser than in the last and the umbilical margin is more pronounced and bears a ridge occupied with small tubercles. Remarks Serometacoceras arasense gen. et sp. nov. differs from S. costale (Shimansky, 1965) gen. et comb. nov. in the shape of the whorl profile; in S. arasense the ww/wh ratio is about 0.90 and in S. costale only 0.60– 0.70 (Shimansky 1965b). In addition, S. arasense has significantly coarser radial ribs than S. costale. Serometacoceras arasense gen. et sp. nov. differs from the other species of the genus Serometacoceras gen. nov. of Julfa by the prominent umbilical margin in the adult stage. Fig. 24. Serometacoceras arasense gen. et sp. nov., holotype MB.C.29349 (Korn et al. 2011 Coll.) from the Zal Member of the Ali Bashi Formation (9.50 m below top) at from Aras Valley. A. Reconstruction of apertural view. B. Lateral view. Scale bar units = 1 mm. Table 14. Conch dimensions (in mm) and ratios of the holotype of Serometacoceras arasense gen. et sp. nov.; estimated values in italics. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.29349 81.5 35.5 38.4 22.8 32.0 0.43 0.92 0.28 2.70 0.17 KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 49 Family Rhiphaeoceratidae Ruzhencev & Shimansky, 1954 Diagnosis Family of the superfamily Pleuronautiloidea with a small, slender first whorl. Whorl profile weakly depressed, elliptical or trapezoidal. Venter broad and weakly convex, flanks convex or slightly flattened and umbilical margin broadly rounded or absent. Sculpture with short ribs on the flank. Suture line with a low external saddle, sometimes with a shallow external lobe, a very shallow lateral and a rather deep funnel-shaped internal lobe; without annular process (after Ruzhencev & Shimansky 1954). Included genera Rhiphaeoceras Ruzhencev & Shimansky, 1954 (Permian); Pararhiphaeoceras Ruzhencev & Shimansky, 1954 (Permian); Sholakoceras Ruzhencev & Shimansky, 1954 (Permian); Rhiphaeonautilus Ruzhencev & Shimansky, 1954 (Permian); Eximioceras Shchedukhin, 2022 (Permian); Alibashinautilus gen. nov. (Permian). Remarks The family Rhiphaeoceratidae can be distinguished from other Permian nautiloids by their suture line with its rather deep internal lobe. The only exceptions are the representatives of the family Aktubonautilidae, but these differ in having a much larger juvenile conch. Genus Alibashinautilus gen. nov. urn:lsid:zoobank.org:act:BD4CEDE2-0145-467A-BD60-AD2C0216959E New genus D – Korn 2025: 55. Type species Alibashinautilus vetus gen. et sp. nov. Diagnosis Genus of the family Rhiphaeoceratidae with subevolute or evolute conch; whorl profile circular or slightly compressed or depressed with broadly rounded venter and flanks. Sculpture with low, rounded radial ribs on the flanks or without ribs. Suture line with shallow external lobe and broadly rounded lateral lobe; internal lobe rather deep, without annular process. Etymology Combination of Ali Bashi and Nautilus; because of the type locality of the type species. Included species NW Iran (this paper): Alibashinautilus vetus gen. et sp. nov., Wuchiapingian; Alibashinautilus ambiguus gen. et sp. nov., Changhsingian. Remarks The new genus comprises species with a simple conch morphology. These are widely umbilicate forms with a circular or weakly compressed whorl profile and a low coiling rate. This morphology distinguishes them from the vast majority of Late Carboniferous and Permian nautilids. The simple morphology of these species makes it challenging to determine their genus and family. It is unclear whether they belong to a conservative evolutionary lineage of simple forms or if they are a result of morphological simplification from more complex forms. The placement of the new genus in the family Rhiphaeoceratidae is based on the shape and sculpture of the shell. Alibashinautilus gen. nov., like Rhiphaeoceras, has a rather simple oval, rounded whorl European Journal of Taxonomy 1018: 1–113 (2025) 50 profile. However, the juvenile conch is not preserved in the Julfa material, so it is not known whether the first whorl is small, as in the Rhiphaeoceratidae, or large, as in the Aktubonautilidae. Therefore, the assignment of Alibashinautilus can only be made with reservations. Alibashinautilus vetus gen. et sp. nov. urn:lsid:zoobank.org:act:4C7D84B1-4455-4069-A54B-3033FEB384A0 Figs 25–27; Table 15 Diagnosis Species of Alibashinautilus gen. nov. with thinly discoidal, evolute conch (ww/dm ~ 0.35; uw/dm ~ 0.50), equidimensional or weakly depressed whorl profile (ww/wh ~ 1.10–1.30) and moderately high coiling rate (WER ~ 1.85) at a conch diameter of 100–140 mm. Whorl profile nearly circular with continuously rounded venter and flanks; whorl overlap very small. Sculpture with short, coarse ribs on the outer flank. Suture line with wide and very shallow external lobe, very shallow lateral lobe and rather narrow, deep internal lobe. Fig. 25. Alibashinautilus vetus gen. et sp. nov., holotype MB.C.32053 (Ghaderi 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Aras Valley; lateral and ventral views. Scale bar units = 1 mm. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 51 Etymology From the Latin ‘vetus’ (adj., m.) = ‘old’; since the species has a morphology similar to that of much older nautiloids. Type material Holotype IRAN – West Azerbaijan • Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Figs 25, 26A–B; MB.C.32053. Fig. 26. Alibashinautilus vetus gen. et sp. nov. A. Holotype MB.C.32053 (Ghaderi 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Aras Valley, reconstruction of apertural view. B. The same specimen, suture line at dm = 94.0 mm, ww = 32.5 mm, wh = 26.5 mm. C. Paratype MB.C.32054 (Ghaderi 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Ali Bashi, main valley, lateral view. D. The same specimen, whorl profile. E. The same specimen, suture line at ww = 35.4 mm, wh = 30.2 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 52 Paratypes IRAN – East Azerbaijan • 1 specimen; Ali Bashi, main valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 26C–E; MB.C.32054 • 1 specimen; Ali Bashi; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); illustrated in Fig. 27; GLM#GH1006. Description Holotype MB.C.32053 is an incomplete internal mould with a diameter of almost 140 mm (Fig. 25). The study of conch shape and sculpture is only possible for about three quarters of the last volution, as the inner whorls are poorly preserved due to recrystallisation. The conch is thinly discoidal and evolute (ww/dm = 0.30; uw/dm = 0.50) and the whorl profile is nearly circular and slightly depressed (ww/ wh = 1.09). The overlap zone of the whorls is very small (Fig. 26A) and the coiling rate is moderately high (WER = 1.85). Fig. 27. Alibashinautilus vetus gen. et sp. nov., paratype GLM#GH1006 from the Araxoceras Beds of the Julfa Formation from Julfa, ventral and lateral views. Scale bar units = 1 mm. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 53 The sculpture consists of prominent ribs, which are coarsest in the ventrolateral region and gradually decrease in strength towards the umbilicus. On the body chamber, these ribs become weaker, and at the greatest diameter of the specimen, only shallow radial folds remain. Half a volution has thirteen ribs. The suture line shows shallow undulation with broadly rounded lobes and saddles and a rather narrow, rounded internal lobe (Fig. 26B). Paratype MB.C.32054 is a whorl segment of nearly half a volution and comprising of two chambers of the phragmocone and a long portion of the body chamber (Fig. 26C). Its conch diameter can be estimated with about 132 mm. The conch is serpenticonic with a wide umbilicus (uw/dm ~ 0.52) and a weakly depressed subcircular whorl profile (ww/wh = 1.28). The coiling rate is moderate (WER ~ 1.91) and the whorl overlap zone very small (Fig. 26D). The sculpture is composed of low ribs confined to the flanks. They are coarsest in the ventrolateral area and become continuously weaker across the flanks before they disappear near the umbilicus. The siphuncle has a subcentral position on the dorsal side at about a quarter of the whorl heigh. Remarks Alibashinautilus vetus gen. et sp. nov. can be easily distinguished from A. ambiguus gen. et sp. nov. by the coarser ribs on the outer flank. Other differences are the greater width of the umbilicus (uw/dm ~ 0.50 in A. vetus, but only ~ 0.37 in A. ambiguus) and the lower coiling rate (WER ~ 1.85 in A. vetus in contrast to ~ 2.30 in A. ambiguus). Alibashinautilus ambiguus gen. et sp. nov. urn:lsid:zoobank.org:act:581650DC-6AA3-4D6E-9DA5-5409F4945D92 Fig. 28; Table 16 Diagnosis Species of Alibashinautilus gen. nov. with thinly discoidal, subevolute conch (ww/dm ~ 0.35; uw/dm ~ 0.35), weakly circular whorl profile (ww/wh ~ 1.00) and very high coiling rate (WER ~ 2.30) at a conch diameter of 120 mm. Whorl profile nearly circular with continuously rounded venter and flanks; whorl overlap very small. Ornament without ribs. Suture line with wide and very shallow external lobe and very shallow lateral lobe. Etymology From the Latin ‘ambiguus’ (adj.) = ‘questionable’; because of the unclear assignment of the species. Type material Holotype IRAN – East Azerbaijan • Ali Bashi 4; Paratirolites Limestone (1.50 m below top) of the Ali Bashi Formation (late Changhsingian); 2011; Korn et al. leg.; illustrated in Fig. 28; MB.C.32055. Table 15. Conch dimensions (in mm) and ratios of Alibashinautilus vetus gen. et sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32053 139.4 42.4 38.5 69.5 37.0 0.30 1.10 0.50 1.85 0.04 MB.C.32053 101.4 34.2 28.4 48.4 26.5 0.34 1.20 0.48 1.83 0.07 MB.C.32054 132.0 49.2 38.5 69.0 36.5 0.37 1.28 0.52 1.91 0.05 European Journal of Taxonomy 1018: 1–113 (2025) 54 Description Holotype MB.C.32055 has a conch diameter of 120 mm and suffered from some corrosion (Fig. 28B). However, it allows the study of the conch shape and proportions across one volution. The whorl profile is nearly circular with a very small overlap upon the preceding volution (Fig. 28A). There is no sculpture visible; the conch appears to be smooth. Almost the entire specimen is chambered; the suture line is almost straight. Despite of corrosion, it is clear that there are no ribs or other sculpture. Remarks Alibashinautilus ambiguus gen. et sp. nov. is distinguished from A. vetus gen. et sp. nov. by the lack of ribs on the outer flank. Other differences are the narrower umbilicus (uw/dm ~ 0.37 in A. ambiguus, but ~ 0.50 in A. vetus) and the higher coiling rate (WER ~ 2.30 in A. ambiguus in contrast to ~ 1.85 in A. vetus). Fig. 28. Alibashinautilus ambiguus gen. et sp. nov., holotype MB.C.32055 (Korn et al. 2011 Coll.) from the Paratirolites Limestone (1.50 m below top) of the Ali Bashi Formation at Ali Bashi 4. A. Reconstruction of apertural view. B. Lateral view. Scale bar units = 1 mm. Table 16. Conch dimensions (in mm) and ratios of Alibashinautilus ambiguus gen. et sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32055 120.3 43.1 42.7 44.3 41.0 0.36 1.01 0.37 2.30 0.04 MB.C.32055 79.3 30.8 31.1 26.5 – 0.39 0.99 0.33 – – KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 55 Alibashinautilus sp. Fig. 29 Material examined IRAN – West Azerbaijan • 1 specimen; Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 29; MB.C.32056. Description Specimen MB.C.32056 is a body chamber fragment (Fig. 29A) with a whorl height of 30 mm and a whorl width of 26 mm. The whorl profile is almost perfectly oval and is only influenced by a very small whorl overlap zone (Fig. 29B). The specimen shows quite coarse and broadly rounded, straight ribs on the flank. Remarks The single specimen most probably represents an own, independent species, but its fragmentary preservation does not provide sufficient data for a clear characterisation. It is thus kept in open nomenclature. Family Foordiceratidae Korn, 2025 Diagnosis Family of the superfamily Tainoceratoidea with a trapezoidal whorl profile; ventrolateral shoulder rounded, flanks strongly divergent. Sculpture with ventrolateral conical nodes, sometimes with low ribs on the flank. Suture line with shallow lobes and low saddles. Internal lobe very shallow, without annular process (from Korn 2025). Included genera Foordiceras Hyatt, 1893 (Permian); Araxonautilus Shimansky, 1979 (Permian); Tardunautilus gen. nov. (Permian). Remarks A detailed discussion of Foordiceras and genera with similar morphology has been given by Korn (2025). Fig. 29. Alibashinautilus sp., specimen MB.C.32056 (Ghaderi 2018 Coll.) from the Araxoceras Beds of the Julfa Formation at Aras Valley. A. Lateral view. B. Whorl profile. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 56 Genus Tardunautilus gen. nov. urn:lsid:zoobank.org:act:A29DB483-82CF-4C67-AC41-D6FBE9C79244 New genus E – Korn 2025: 56. Type species Tardunautilus nimius gen. et sp. nov. Diagnosis Genus of the family Foordiceratidae with evolute conch; whorl profile rounded triangular or rounded trapezoidal, depressed with broadly rounded venter. Sculpture with one or two rows of conical ribs near the ventrolateral shoulder. Suture line with very shallow external lobe and broadly rounded lateral lobe; without annular process. Etymology From the Latin ‘tardus’ (adj., m.) = ‘slow’; because of the low coiling rate of the conch, and ‘nautilus’ because of the relationship. Included species NW Iran (this paper): Tardunautilus nimius gen. et sp. nov., Wuchiapingian; Tardunautilus minor gen. et sp. nov., Wuchiapingian. Central Iran (Korn & Hairapetian in press): new species J to be described by Korn & Hairapetian (in press), Wuchiapingian. Remarks The new genus can be easily distinguished from all other genera in the assemblage of Julfa because of its combination of a conch shape with a wide umbilicus, a rounded triangular or rounded trapezoidal whorl profile and a sculpture consisting of conical nodes. A genus with a similar morphology is Pseudotemnocheilus, but this is mostly known from much smaller specimens of about 40–60 mm in diameter. These smaller specimens have a much narrower umbilicus (uw/dm ~ 0.40) compared to Tardunautilus gen. nov. (uw/dm ~ 0.47) and a less depressed whorl profile (ww/wh ~ 1.30) than Tardunautilus (ww/wh ~ 1.40–1.80). The coiling rate is much lower in Tardunautilus (WER below 2.00) when compared to Pseudotemnocheilus (WER greater than 2.25). Tardunautilus nimius gen. et sp. nov. urn:lsid:zoobank.org:act:6A04A10E-B527-425A-8438-848513FDD2E5 Figs 30–31; Table 17 Diagnosis Species of Tardunautilus gen. nov. with thickly discoidal, evolute conch (ww/dm ~ 0.53; uw/dm ~ 0.47), moderately depressed whorl profile (ww/wh ~ 1.80) and moderately high coiling rate (WER ~ 1.95) at a conch diameter of 150 mm. Whorl profile rounded trapezoidal with strongly divergent flanks; venter broadly rounded, area of flanks and umbilical wall weakly concave. Sculpture with two rows of ventrolateral nodes in the intermediate growth stage. Suture line with very broad and shallow external lobe, slightly deeper, broadly rounded lateral lobe and broadly rounded internal lobe. Etymology From the Latin ‘nimius’ (adjective, m.) = ‘very large’; because of the large size of the conch. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 57 nodes, in some species with rows of nodes on the flank. Septa simply domed; suture line depending on the whorl profile, usually with shallow lobes and low saddles (from Korn 2025). Included genera Tainoceras Hyatt, 1883 (Carboniferous to Permian); Tainionautilus Mojsisovics, 1902 (Permian to Triassic); Tirolonautilus Mojsisovics, 1902 (Permian); Tylonautilus Pringle & Jackson, 1928 (Carboniferous to ?Permian); Aulametacoceras Miller & Unklesbay, 1942 (Permian); Hexagonites Hayasaka, 1947 (Permian); Hunanoceras Chao, 1954 (Permian); Hefengnautilus Xu, 1977 (Permian); Clavinautilus Zhao, Liang & Zheng, 1978 (Permian); Eulomacoceras Zhao, Liang & Zheng, 1978 (Permian); Lirometacoceras Zhao, Liang & Zheng, 1978 (Permian); Neotainoceras Zhao, Liang & Zheng, 1978 (Permian;); Paratainonautilus Zhao, Liang & Zheng, 1978 (Permian); Seironautilus Zhao, Liang & Zheng, 1978 (Permian); Neoclavinautilus Liang, 1984 (Permian); Nodonautilus Liang, 1984 (Permian); Nodopleuroceras Zheng, 1984 (Permian); Meixianlingites Qin, 1986 (Permian); Paratainoceras Qin, 1986 (Permian); Siamnautilus Ishibashi et al., 1994 (Permian); Gujiaonautilus Miao et al., 2019 (Permian); new genus D to be described by Korn & Hairapetian (in press) (Permian); Corotainoceras gen. nov. (Permian). Remarks A detailed discussion of family Tainoceratidae has been given by Korn (2025). Genus Tainoceras Hyatt, 1883 Type species Nautilus quadrangulus McChesney, 1860; original designation. Diagnosis Genus of the family Tainoceratidae with a subinvolute or subevolute conch; whorl profile more or less strongly depressed, ranging from subquadrate and hexagonal to polygonal with a distinct midventral longitudinal groove. Umbilical margin usually pronounced and subangular in the intermediate stage, rounded in the adult stage. Sculpture usually with two rows of conical nodes on the venter and additional rows on the flank. Septa simply domed, suture line strongly depending on the shape of the whorl profile, usually with shallow external lobe and broadly rounded lateral lobe. Siphuncle small with subcentral position ventrad of septum centre. Included Carboniferous species North America (McChesney 1860; Miller et al. 1933; Miller & Unklesbay 1942; Lintz 1958; Tucker & Mapes 1978; Sturgeon et al. 1982): Nautilus quadrangulus McChesney, 1860, Gzhelian, Illinois; Nautilus nodocarinatus McChesney, 1860, Gzhelian, Illinois; Tainoceras monilifer Miller, Dunbar & Condra, 1933, Gzhelian, Texas; Tainoceras rotundatum Miller, Dunbar & Condra, 1933, Gzhelian, Texas; Tainoceras murrayi Miller & Unklesbay, 1942, Gzhelian, Nebraska; Metacoceras marylandica Lintz, 1958, Gzhelian, Maryland; Tainoceras sexlineatum Tucker, 1976, Kasimovian, Illinois; Tainoceras collinsi Sturgeon, Windle, Mapes & Hoare, 1982, Gzhelian, Ohio. Donets Basin (Dernov 2024): Tainoceras luxaeterna Dernov, 2024, Kasimovian. Western Russia (Waagen 1879): Nautilus Trautscholdi Waagen, 1879, Gzhelian, Moscow Basin. European Journal of Taxonomy 1018: 1–113 (2025) 64 Included Permian species North America (Swallow 1860; Hyatt 1891, 1893; Miller et al. 1933; Miller & Thomas 1936; Miller & Unklesbay 1942; Miller & Kemp 1947; Miller & Youngquist 1949): Nautilus occidentalis Swallow, 1860, Artinskian, Kansas; Tainoceras cavatum Hyatt, 1891, Asselian, Texas; Tainoceras Duttoni Hyatt, 1893, Asselian, New Mexico; Tainoceras nebrascense Miller, Dunbar & Condra, 1933, Artinskian, Nebraska; Tainoceras wyomingense Miller & Thomas, 1936, Asselian, Wyoming; Tainoceras schellbachi Miller & Unklesbay, 1942, Kungurian, Arizona; Tainoceras clydense Miller & Kemp, 1947, Kungurian, Texas; Tainoceras unklesbayi Miller & Youngquist, 1949, Kungurian, Texas. Alps and Southern Europe (Gemmellaro 1889; Simić 1933; Schréter 1974; Prinoth & Posenato 2007): Pleuronautilus Toulai Gemmellaro, 1890, Wordian, Sicily; Tainoceras zmajevatense Simić, 1933, Wuchiapingian, Serbia; Tainoceras bükkense Schréter, 1974, Changhsingian, Bűkk Mountains; Tainoceras crassicostatum Schréter, 1974, Changhsingian, Bűkk Mountains; Tainoceras balestense Prinoth & Posenato, 2007, Changhsingian, Dolomites; Tainoceras malsineri Prinoth & Posenato, 2007, Changhsingian, Dolomites. NW Iran (this paper): Tainoceras admonens sp. nov., Wuchiapingian; Tainoceras latecostatum sp. nov., Wuchiapingian; Tainoceras unitum sp. nov., Changhsingian. Central Iran (Korn & Hairapetian in press): new species N to be described by Korn & Hairapetian (in press), Changhsingian, Central Iran. Pakistan (Reed 1931, 1944): Tainoceras Noetlingi var. subglobosa Reed, 1931, Wuchiapingian, Salt Range; Tainoceras comptum Reed, 1944, Changhsingian, Salt Range; Tainoceras debile Reed, 1944, Changhsingian, Salt Range; Tainoceras trimuense Reed, 1944, Wuchiapingian, Salt Range. South China (Kayser 1883; Chao 1954; Zheng 1984): Nautilus mingshanensis Kayser, 1883, Wuchiapingian, Jiangxi; Nautilus orientalis Kayser, 1883, Wuchiapingian, Jiangxi; Tainoceras changlingpuense Chao, 1954, Roadian, Hunan; Tainoceras hunanense Chao, 1954, Roadian, Hunan; Tainoceras gibbosum Zheng, 1984, Changhsingian, Guizhou; Tainoceras guizhouense Zheng, 1984, Changhsingian, Guizhou; Tainoceras lateronodosum Zheng, 1984, Changhsingian, Guizhou. Japan (Hayasaka 1957, 1962; Ehiro & Araki 1997): Tainoceras abukumense Hayasaka, 1957, Capitanian; Tainoceras kitakamiense Hayasaka, 1962, Roadian; Tainoceras carinatum Ehiro & Araki, 1997, Capitanian. Remarks Tainoceras is the typical representative of the family, superfamily and suborder named after it and is considered one of the cardinal genera within the order Nautilida. About 40 species of Tainoceras have been described so far and the genus has a long stratigraphic range extending from the latest Carboniferous to the latest Permian. However, only a few efforts have been made to clearly define the genus in its morphological range. While Miller et al. (1933: 147) and Miller & Youngquist (1949: 80) gave a detailed characterisation of the genus, Shimansky (1962b: 121) and Kummel (1964: K413) characterised the genus Tainoceras with just one sentence: “Like Metacoceras but with a double row of nodes on the venter.” Sturgeon et al. (1997: 29) were more precise: “Similar to Metacoceras but possessing two ventral rows of nodes or ribs separated by a median sulcus.” They gave a more detailed outline of the characters typically present in Tainoceras. It is apparent that a simple definition is not adequate to define the rather complex genus, especially in respecting the fact that other tainoceratid genera have been established in recent decades. A precise KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 65 morphological delineation and taxonomic interpretation of Tainoceras requires a discussion of several questions: (1) What are the morphological characters that can be used to clearly distinguish Tainoceras from other genera? (2) Are the tainoceratids (Tainoceras and derived genera of the Late Permian) really a monophyletic unit? (3) Did long-ranging evolutionary lineages with stable morphology exist within Tainoceras, or did similar conch shapes and sculptures emerge iteratively and independently? The first question is not easy to answer. The previously used character of a double row of ventral nodes cannot be used universally as a cardinal separating character because some species have only one row of ventral nodes or no ventral nodes at all in the adult stage (e.g., the Late Carboniferous T. collinsi and T. marylandicum and the Late Permian T. balestense). Instead, other supporting characters, such as the presence of the midventral groove, must be used. It should be made clear that in Tainoceras this groove incurves a broadly rounded venter. This is in contrast to genera such as Metacoceras, in which a concave venter, if present at all, always occurs as a shallow depression of the entire venter. The second question is easier to answer. Although the morphological spectrum of Tainoceras is rather broad and somewhat variable, the combination of several morphological characters, such as the presence of the midventral groove, the rows of nodes on the venter and ventrolateral shoulder and the pronounced umbilical margin, suggests a monophyletic series of forms. Due to the complexity of the morphology, a polyphyletic origin of Tainoceras can be excluded. To answer the third question, it is necessary to evaluate the characters of conch geometry and sculpture with regard to their variation within the genus Tainoceras. The following characters have proven to be particularly variable (with some representative examples): - General shape of the whorl profile: it can range from rectangular (T. nebrascense) to octagonal or polygonal (T. clydense, T. admonens sp. nov.); the ww/wh ratio can range from approximately equidimensional (T. cavatum) to weakly depressed (T. schellbachi, T. admonens sp. nov.) and moderately depressed (T. duttoni). - General shape of the venter: in all of the species, the venter is more or less tripartite, but the degree of tripartition varies from weak with nearly convex venter (T. cavatum) to very strong with clearly defined ventrolateral applanation forming a tectiform venter (T. clydense, T. duttoni). - Arrangement and shape of the flanks: the flanks can be divergent (T. quadrangulum, T. admonens sp. nov.), parallel (T. quadrangulum) or convergent (T. duttoni). They can be flattened (T. cavatum) or weakly concave (T. duttoni, T. admonens). - Shape of the umbilical margin and umbilical wall: while the umbilical margin is usually narrowly rounded (T. nebrascense) or subangular (T. duttoni), the umbilical wall ranges from oblique (T. cavatum, T. clydense) to steep (T. duttoni) and from weakly convex (T. nebrascense) to flattened (T. duttoni, T. admonens sp. nov.). - Width and depth of the midventral groove: the groove can vary from narrow (T. nebrascense, T. clydense) to wide (T. schellbachi, T. admonens sp. nov.) and from shallow (T. collinsi, T. cavatum, T. admonens) to deep (T. duttoni, T. wyomingense). - Formation of the ventral nodes: ventral sculptural elements may appear as short plications (T. collinsi), small tubercles (T. nebrascense, T. monilifer, T. nodocarinatum, T. admonens sp. nov.), or also large conical, blunt nodes (T. clydense) or pointed nodes or spines (T. quadrangulum, T. schellbachi). Some species possess coarse ventral transverse ribs (T. unklesbayi). The ventral tubercles may be arranged symmetrically (T. nebrascense) or alternating on the right and left sides of the midventral groove (T. monilifer). European Journal of Taxonomy 1018: 1–113 (2025) 66 - Formation of lateral ribs: lateral ribs do not occur in many of the North American species, but are present in species from other regions (T. debile, T. admonens sp. nov.). - Formation of umbilical nodes: umbilical sculptural elements are present in some species; they range from being small tubercles (T. clydense) to large conical nodes (T. schellbachi). The list of mostly bipolar character pairs shows numerous theoretically possible combinations; however, covariation is very common and some of the characters often appear simultaneously. Tainoceras admonens sp. nov. urn:lsid:zoobank.org:act:962E20FB-58E7-40B0-B125-55893A5F1495 Fig. 34; Table 20 Tainoceras (?) sp. – Gliwa et al. 2020: text-fig. 17c. Diagnosis Species of Tainoceras with thinly pachyconic, subevolute conch (ww/dm ~ 0.65; uw/dm ~ 0.32), weakly depressed whorl profile (ww/wh ~ 1.45) and extremely high coiling rate (WER ~ 2.85) at a conch diameter of 50 mm. Whorl profile polygonal with convergent flanks; venter tectiform with broad longitudinal midventral groove, flanks weakly concave, umbilical margin narrowly rounded. Sculpture with about 12 faint ribs on the flank per volution, strengthened to form small, longitudinally elongated tubercles on the ventrolateral shoulder. Suture line with a shallow, tongue-shaped external lobe and a broadly rounded, very shallow lateral lobe. Etymology From the Latin ‘admonens’ (verb in participle) = ‘reminding’; because of the similar conch geometry with the Late Carboniferous species of the genus. Type material Holotype IRAN – West Azerbaijan • Aras Valley; Vedioceras Beds of the Julfa Formation (late Wuchiapingian); 2011; Korn et al. leg.; illustrated in Fig. 34D–F; MB.C.29348. Paratype IRAN – West Azerbaijan • 1 specimen; same data as for holotype; illustrated in Fig. 34A–C; MB.C.32060. Description Holotype MB.C.29348 is a partly corroded specimen, but nevertheless allows examination of the conch geometry, sculpture and suture line (Fig. 34D). It has a conch diameter of 48 mm and is fully chambered. The conch is thinly pachyconic and subevolute (ww/dm = 0.65; uw/dm = 0.32) with an extremely high coiling rate (WER = 2.80) and a very small whorl overlap zone. The whorl profile is weakly depressed whorl profile (ww/wh = 1.44) and polygonal with divergent, concave flanks; the umbilical margin is narrowly rounded and the umbilical wall is flattened. The ventrolateral shoulder is pronounced and subangular; it delimits the broad venter, which is rounded-tectiform in cross section and possesses three concave zones, of which the central is the deepest (Fig. 34E). The sculpture consists of faint, longitudinally elongated conical tubercles with a position on the ventrolateral shoulder. There are about 15 of such tubercles per volution. The venter bears one row of very low, blunt tubercles on each side adjacent to the longitudinal groove. These tubercles do not correspond to the riblets on the flank and are KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 67 more numerous. The suture line is undulated with very shallow lobes in the concave parts of the conch (Fig. 34F). Paratype MB.C.32060 is a rather strongly corroded specimen, but nevertheless allows examination of the conch geometry, sculpture and suture line. It has a conch diameter of 56 mm and is fully chambered (Fig. 34A). The conch is thinly pachyconic and subevolute (ww/dm = 0.67; uw/dm = 0.32) with an extremely high coiling rate (WER = 2.89) and a very small whorl overlap zone. The whorl profile is moderately depressed whorl profile (ww/wh = 1.50) is generally rounded polygonal with slowly divergent, weakly concave flanks; the umbilical margin is narrowly rounded and the umbilical wall is flattened. The ventrolateral shoulder is pronounced and delimit the broad venter, which is convex in cross section, but possesses three concave zones, of which the central is the deepest (Fig. 34B). The sculpture consists of low, longitudinally elongated conical tubercles with a position on the ventrolateral shoulder. There are about 12 of such ribs per volution. The venter bears one row of very low, barely visible nodes on both sides of the longitudinal groove. The suture line is undulated with very shallow lobes in the concave parts of the conch (Fig. 34C). Fig. 34. Tainoceras admonens sp. nov. A. Paratype MB.C.32060 (Korn et al. 2011 Coll.) from the Vedioceras Beds of the Julfa Formation at Aras Valley, lateral and apertural views. B. The same specimen, reconstruction of apertural view. C. Suture line at dm = 57.5 mm, ww = 36.0 mm, wh = 22.6 mm. D. Holotype MB.C.29348 (Korn et al. 2011 Coll.) from the Vedioceras Beds of the Julfa Formation at Aras Valley, lateral and apertural views. E. The same specimen, reconstruction of apertural view. F. Suture line at dm = 32.6 mm, ww = 22.8 mm, wh = 10.7 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 68 Remarks Tainoceras admonens sp. nov. has, because of its very weak sculpture, a marginal position in the morphological spectrum of the genus. Particularly the weak ribs on the flank and the presence of only one row of ventral nodes distinguishes the new species from the others of the genus. The general conch shape and the sculpture are similar to the stratigraphically older species of the genus, such as the Late Carboniferous type species T. quadrangulum, but the new species differs in the considerably weaker developed ventrolateral and ventral tubercles. The Early Permian T. clydense is more similar, especially in the non-corresponding ventral and ventrolateral tubercles. However, the ventral nodes in T. clydense are much higher than in T. admonens sp. nov. In addition, the umbilicus in T. clydense is narrower (uw/dm ~ 0.25) than in T. admonens (uw/dm ~ 0.30). Tainoceras latecostatum sp. nov. urn:lsid:zoobank.org:act:69764943-0130-453D-9EB0-B478EC4E6515 Fig. 35; Table 21 Diagnosis Species of Tainoceras with discoidal, subevolute conch (ww/dm ~ 0.45; uw/dm ~ 0.33) and weakly depressed whorl profile (ww/wh ~ 1.15) at a conch diameter of about 100 mm. Whorl profile hexagonal with gently convergent flanks; venter tectiform with broad longitudinal midventral groove, flanks flattened, umbilical margin narrowly rounded. Sculpture with about 20 sharp, coarse ribs on the flank per volution; venter with one row of hump-like, low nodes adjacent to the longitudinal groove. Suture line with a rather deep, tongue-shaped external lobe and a broadly rounded lateral lobe. Etymology Combination of the Latin ‘late’ (adv.) = ‘broadly’ and ‘costatum’ (adj., n.) = ‘ribbed’; because of the coarse ribs on the flanks. Type material Holotype IRAN – East Azerbaijan • Ali Bashi 4; Vedioceras Beds of the Julfa Formation (late Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 35; MB.C.32061. Description Holotype MB.C.32061 is a fragment of a phragmocone with an estimated conch diameter of 95 mm (Fig. 35B). It is slightly tectonically distorted, but nevertheless allows the conch geometry to be recognised quite well; it can be estimated that the width of the umbilicus is about one third of the conch diameter. The whorl profile is weakly depressed with a whorl width of 45 mm and a whorl height of 39 mm; the venter is convex and has a median longitudinal groove with a width of about 12 mm. The weakly convergent flanks are flattened and bordered by a rounded ventrolateral shoulder and a rounded umbilical margin (Fig. 35A). Table 20. Conch dimensions (in mm) and ratios of Tainoceras admonens sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32060 56.4 37.6 25.0 17.9 23.2 0.67 1.50 0.32 2.89 0.07 MB.C.32060 33.2 23.2 15.0 9.6 – 0.70 1.55 0.29 – – MB.C.29348 48.0 31.2 21.6 15.5 19.3 0.65 1.44 0.32 2.80 0.11 MB.C.29348 27.7 19.6 11.0 8.7 – 0.71 1.78 0.31 – – KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 69 The sculpture consists of a combination of ribs and nodes. On the flank, five very strong ribs are present on a quarter of a volution; these begin at a short distance from the umbilical margin and extend in slight forward direction with a shallow lateral sinus across the flank. In the ventrolateral region they increase in strength and form sharp ridges ending in ventrolateral nodes. These continue a short distance towards the lateral side of the venter, where they are directed backwards. Very low and bluntly rounded hump-like conical nodes occur immediately adjacent to the median longitudinal groove; these nodes correspond to the ribs on the flanks. The suture line shows a tongue-shaped external lobe and a broadly rounded lateral lobe (Fig. 35C). Remarks A new species is established here, although only one fragmentary specimen is available. The reason for this is the peculiar sculpture of Tainoceras latecostatum sp. nov., which consists of a combination of ribs on the flanks and one row of very low, hump-like nodes on the venter. It is especially the coarse ribs that give the new species a unique position in the genus; other species possess conical nodes on the flanks instead. In lateral view, with the narrowly rounded umbilical margin, the flattened flanks and the somewhat concave ribs, the new species bears some resemblance to the species of the genus Serometacoceras gen. nov., but differs in the ventral longitudinal groove and the ventral nodes. Fig. 35. Tainoceras latecostatum sp. nov., holotype MB.C.32061 (Ghaderi 2018 Coll.) from the Vedioceras Beds of the Julfa Formation at Ali Bashi 4. A. Whorl profile. B. The same specimen, lateral and ventral views. C. The same specimen, suture line at wh = 27.0 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 70 Tainoceras unitum sp. nov. urn:lsid:zoobank.org:act:1F60FF8F-3ABB-4B98-ABED-853626335165 Fig. 36 Diagnosis Species of Tainoceras with thinly pachyconic, subevolute conch and nearly quadrate whorl profile (ww/wh ~ 1.10) at a conch diameter of about 80 mm. Whorl profile with weakly convergent flanks; venter flattened with a broad longitudinal midventral groove, flanks sinuous, umbilical margin narrowly rounded. Sculpture with five coarse ribs per quarter volution, extending from the umbilical margin to the midventral groove, strengthened to form small, longitudinally elongated nodes on the ventrolateral shoulder and the venter. Suture line with a very shallow external lobe and a broadly rounded, very shallow lateral lobe. Etymology From the Latin ‘unitum’ (verb in participle) = ‘united’; because of the amalgamated ventrolateral and ventral nodes. Type material Holotype IRAN – West Azerbaijan • Zal; Zal Member of the Ali Bashi Formation (early Changhsingian); 2018; Ghaderi leg.; illustrated in Fig. 36; MB.C.32062. Description The fragmentary holotype MB.C.32062 has a whorl height of 30 mm and thus may belong to a specimen with a conch diameter of about 80 mm (Fig. 36A). Its whorl profile is almost quadrate but slightly depressed (ww/wh = 1.06) with narrowly rounded umbilical margin, flattened slowly converging flanks, rounded ventrolateral shoulders and a flattened venter with a shallow and broad longitudinal groove (Fig. 36B). The sculpture of the fragment shows five rounded ribs on the whorl segment of 90 degrees. These ribs are slightly concave in their course; they begin on the inner flanks and become more prominent to terminate in pronounced ventrolateral nodes, which have a position on the outer flank. On the venter, another row of nodes is present adjacent to the ventral groove. The ventrolateral and ventral nodes are corresponding and connected by a blunt rib. The suture line is weakly undulate with very shallow, broadly rounded external and lateral lobes (Fig. 36C). Remarks Tainoceras unitum sp. nov. has a similar conch shape and sculpture to that of T. latecostatum sp. nov., but differs in the blunt flank ribs (which are sharp in T. latecostatum) and the much thicker ventral nodes, which are very weakly developed in T. latecostatum. Another difference between the two species is the rib-like connection of the ventrolateral and ventral nodes in T. unitum, whereas these are separate in T. latecostatum. Tainoceras unitum sp. nov. differs from many other species of the genus in the presence of flank ribs. In addition, the almost complete fusion of the ventrolateral and ventral nodes is not developed in the other species. Table 21. Estimated conch dimensions (in mm) and ratios of Tainoceras latecostatum sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32061 95 45 39 – – 0.47 1.15 – – – KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 71 New genus D Korn & Hairapetian (in press) Type species New species O to be described by Korn & Hairapetian (in press); original designation. Diagnosis Genus of the family Tainoceratidae with subinvolute or subevolute conch; whorl profile depressed and polygonal with a shallow or broad midventral longitudinal groove. Umbilical margin pronounced and narrowly rounded, flanks convergent. Sculpture with one row of nodes on the ventrolateral shoulder. Suture line strongly depending on the shape of the whorl profile, with rounded V-shaped external lobe and broadly rounded lateral lobe (from Korn & Hairapetian in press). Included species Transcaucasia (Abich 1878): Nautilus dorso plicatus Abich, 1878, Wuchiapingian, Azerbaijan. Central Iran (Korn & Hairapetian in press): new species O to be described by Korn & Hairapetian (in press), Wuchiapingian. Remarks According to Korn & Hairapetian (in press), the new genus D is a genus with a morphology that is similar to that of some species of Tainoceras, but with a much less developed sculpture. In contrast to Tainoceras, which usually has two rows of nodes or tubercles in the ventrolateral region and sometimes another row of nodes on the inner flank, the new genus D has only one row of nodes, located on each side immediately adjacent to the median longitudinal groove, but lacks another row in the ventrolateral region. With a simplification of the sculpture, the new genus may be derived from Tainoceras. Corotainoceras also shows simplification of the sculpture, but differs from the new genus D in the absence of ventrolateral nodes and the presence of very coarse dorsolateral nodes. Fig. 36. Tainoceras unitum sp. nov., holotype MB.C.32062 (Ghaderi 2018 Coll.) from the Zal Member of the Ali Bashi Formation at Zal. A. Ventral and lateral views. B. Whorl profile. C. Suture line at ww = 26.5 mm, wh = 26.0 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 72 New genus D dorsoplicatum (Abich, 1878) Fig. 3A–B Nautilus dorso plicatus Abich, 1878: 23, pl. 2 fig. 6, pl. 3 fig. 1, pl. 4 fig. 8. Coelonautilus dorsoplicatus – von Arthaber 1900: 217. Tainoceras dorsoplicatum – Shimansky 1965a: 41, pl. 14, fig. 1. Remarks Abich (1878) illustrated two fragments as “Nautilus dorso plicatus, nov. form.”. The first of these (Abich 1878: pl. 4 fig. 8) has a whorl height of about 27 mm. It shows rounded, strongly convergent flanks and a venter with a longitudinal midventral groove about 15 mm wide (Fig. 3B). This groove is bordered on both sides by a slightly raised margin that is decorated with large, blunt nodes. Ventrolateral nodes are obviously lacking. The suture line has a fairly narrow, rounded lobe on the venter and a broad, rounded lobe on the flank. The second specimen (Abich 1878: pl. 2 fig. 3, pl. 3 fig. 1) has a whorl width of about 35 mm (Fig. 3A) and corresponds to the larger one in conch shape and sculpture. The specimen has a broadly rounded umbilical margin. It shows that there are neither ventrolateral nor umbilical nodes; the flank appears to be smooth. New genus D dorsoplicatum occupies a morphologically isolated position in the family Tainoceratidae due to the presence of only a single row of ventral nodes. The species is probably not represented in the new collections from NW Iran. Genus Corotainoceras gen. nov. urn:lsid:zoobank.org:act:F415AD8C-A2F7-4191-809F-FDC1796B0974 New genus F – Korn 2025: 61. Type species Corotainoceras inerme gen. et sp. nov. Diagnosis Genus of the family Tainoceratidae with subevolute conch; whorl profile depressed and polygonal with a shallow midventral longitudinal groove. Umbilical margin broadly rounded, flanks convergent. Sculpture without nodes on the venter and the ventrolateral shoulder, but with coarse umbilical nodes. Suture line strongly depending on the shape of the whorl profile, with shallow, rounded V-shaped external lobe and broadly rounded lateral lobe. Etymology Combination of the Latin ‘corona’ (noun) = ‘wreath’ and Tainoceras; because of the coronate umbilicus. Included species NW Iran (this paper): Corotainoceras inerme gen. et sp. nov., Wuchiapingian. Remarks The genera of the family Tainoceratidae are generally distinguished on the basis of their sculpture. The new genus differs from all other genera of the family in the absence of ventral and ventrolateral nodes or tubercles. In contrast to most other members of the family Tainoceratidae, the type species of Corotainoceras shows very coarse umbilical nodes. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 73 Description Specimen MB.C.32066 is a badly corroded and thus poorly preserved individual with a diameter of 93 mm (Fig. 40B). It can, however, because of its characteristic longitudinal nodes on the venter on both sides of the deep median groove (Fig. 40), be attributed to the genus Tirolonautilus. These nodes extend, at least at the beginning of the last whorl, as low ribs towards the midflank, where they wedge out. Remarks The conch form and sculpture of the specimen from Julfa bears some resemblance to T. sebedinus from the Dolomites (Prinoth & Posenato 2007). However, the ribs on the flank are noticeably sharper in T. sebedinus and extend towards the umbilical margin. Unfortunately, the poor preservation of the specimen from Ali Bashi precludes a more detailed discussion. Suborder Liroceratina Flower, 1955 Diagnosis Suborder of the order Nautilida, in which an umbilical margin is formed early in ontogeny; advanced species may regress this character. Conch usually pachyconic and rarely discoidal or globular, subinvolute to involute. Juvenile whorl profile circular. Adult whorl profile usually circular or depressed oval without distinct ventrolateral shoulder in the early species, showing modifications during evolution (inverted trapezoidal with convergent flanks and flattened venter). Dorsal whorl zone always present, small to Fig. 40. Tirolonautilus sp. 2, specimen MB.C.32066 (Korn et al. 2011 Coll.) from the Paratirolites Limestone (2.80 m below top) of the Ali Bashi Formation at Ali Bashi 4. A. Lateral view. B. Reconstruction of apertural view. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 80 moderately deep. Juvenile sculpture with spiral lines that may be restricted to the umbilical area in the early species; adult sculpture usually lacking except for spiral lines in some species. Septa simply domed in the early species; with dorsal inflexion in advanced species and with corrugated septa in two derived clades. Suture line depending on the whorl profile, usually with shallow lobes and low saddles; with distinct lobes in two clades (from Korn 2025). Included superfamilies Liroceratoidea Hyatt, 1900 (Carboniferous to Triassic); Ephippioceratoidea Miller & Youngquist, 1949 (Carboniferous to Permian); Clydonautiloidea Hyatt, 1900 (Triassic to Jurassic). Remarks A discussion of the suborder Liroceratina has been given by Korn (2025). Superfamily Liroceratoidea Hyatt, 1900 Diagnosis Superfamily of the suborder Liroceratina with a pachyconic and rarely discoidal or globular, subinvolute to involute conch. Whorl profile usually circular or depressed oval without distinct ventrolateral shoulder; in some species with a pronounced but rounded ventrolateral shoulder. Dorsal whorl zone usually small to moderately deep. Juvenile sculpture in the early species with spiral lines that may be restricted to the umbilical area; derived species are often smooth. Suture line very simple, almost straight across flanks and venter (from Korn 2025). Included families Liroceratidae Miller & Youngquist, 1949 (Carboniferous to Triassic); Coloceratidae Hyatt, 1893 [homonym; synonym of Liroceratidae Miller & Youngquist, 1949]; Paranautilidae Kummel in Flower & Kummel, 1950 (Triassic); Permonautilidae Barskov & Shilovsky, 2014 (Permian); Planetoceratidae Korn, 2025 (Carboniferous); Julfanautilidae fam. nov. (Permian). Remarks A detailed discussion of the Liroceratoidea has been given by Korn (2025). Family Liroceratidae Miller & Youngquist, 1949 Diagnosis Family of the superfamily Liroceratoidea with a usually pachyconic or globular, subinvolute to subevolute conch. Whorl profile in the adult stage usually more or less strongly depressed; flanks and venter form a continuous arch in the early species, the venter can be flattened or concave in advanced species. Umbilical margin rounded; umbilical wall usually convex. Ornament usually consisting of fine growth lines; spiral lines occur in some genera. Septum simple in shape, concavely domed; suture line very simple, almost straight across flanks and venter or with small lobes and saddles (from Korn 2025). Included genera Solenoceras Hyatt, 1884 [homonym of Solenoceras Conrad, 1860; objective synonym of Coelogasteroceras]; Coelogasteroceras Hyatt, 1893 (Carboniferous to Permian); Coloceras Hyatt, 1893 [homonym of Coloceras Taschenberg, 1882; synonym of Liroceras Teichert, 1940]; Stearoceras Hyatt, 1893 (Carboniferous to Permian); Peripetoceras Hyatt, 1894 (Carboniferous to Permian); Potoceras KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 81 Hyatt, 1894 (Carboniferous); Nannoceras Hyatt, 1894 [nomen nullum; synonym of Peripetoceras]; Conradiceras Cossmann, 1900 [objective synonym of Coelogasteroceras]; Liroceras Teichert, 1940 (Carboniferous to Permian); Condraoceras Miller, Lane & Unklesbay, 1947 (Carboniferous to Permian); Periptoceras Chao, 1954 [nomen nullum; synonym of Peripetoceras]; Hemiliroceras Ruzhencev & Shimansky, 1954 (Carboniferous to Permian); Bistrialites Turner, 1954 (Carboniferous); Pseudophacoceras Turner, 1966 (Carboniferous); Neobistrialites Tucker, Mapes & Aronoff, 1978 (Carboniferous); Jianoceras Ma, 1997 (Permian); Nemdoceras Barskov & Shilovsky, 2014 (Permian); Paraliroceras Barskov & Shilovsky, 2014 (Permian); Tatianautilus Barskov & Shilovsky, 2014 (Permian); Leniceras Leonova & Shchedukhin, 2020 (Permian); Shikhanonautilus Leonova & Shchedukhin, 2020 (Permian); Thyoceras Leonova & Shchedukhin, 2020 (Permian); Celeroliroceras gen. nov. (Permian); Perunautilus Crick & Sobolev, 1994 (Triassic); Tomponautilus Sobolev, 1989 (Triassic). Remarks A detailed discussion of the Liroceratidae has been given by Korn (2025). Genus Liroceras Teichert, 1940 Type species Coloceras liratum Girty, 1911; original designation. Diagnosis Genus of the family Liroceratidae with pachyconic to globular, involute or subinvolute conch; umbilicus closed by a plug in some species. The first whorl is 10–20 mm in diameter with a very small umbilical foramen; the conch is rapidly increasing in height with a high coiling rate (WER usually higher than 2.50). Whorls weakly embracing, their profile ranges from reniform to nearly circular. Juvenile conch with longitudinal ridges or lines; adult ornament with growth lines with a fairly deep ventral sinus and spiral lines in some species. Septa without inflexions, slightly concave. Suture line simple, nearly straight with a shallow, broadly rounded internal lobe. The siphuncle has a position between the centre of the septum and the venter (after Gordon 1965; Shimansky 1967). Included Carboniferous species North America (Shumard & Swallow 1858; Miller & Gurley 1897; Girty 1911; Miller et al. 1933; Newell 1936; Unklesbay 1962; Gordon 1965): Nautilus Missouriensis Swallow, 1858, Bashkirian, Missouri; Solenochilus henryvillense Miller & Gurley, 1897, Viséan, Indiana; Coloceras liratum Girty, 1911, Moscovian, Oklahoma; Coloceras liratum var. obsoletum Girty, 1911, Moscovian, Oklahoma; Coloceras greenei Miller, Dunbar & Condra, 1933, Kasimovian, Oklahoma; Coloceras milleri Newell, 1936, Kasimovian, Kansas; Coloceras reticulatum Miller & Owen, 1937, Kasimovian, Oklahoma; Liroceras patulum Unklesbay, 1962, Bashkirian, Arkansas; Liroceras bicostatum Gordon, 1965, Serpukhovian, Arkansas. British Isles (Foord 1891; Hind 1910; Turner 1954; Ramsbottom & Moore 1961): Coelonautilus Derbiensis Foord, 1891, Viséan, Derbyshire; Coelonautilus Derbiensis var. globulare Foord, 1891, Viséan, Isle of Man; Solenocheilus globosus Hind, 1910, Bashkirian, Lancashire; Liroceras lunense Turner, 1954, Serpukhovian, Yorkshire; Liroceras leitrimense Ramsbottom & Moore, 1961, Viséan, Ireland. Central Europe (Trenkner 1868; Hyatt 1894; Miller et al. 1933; Schmidt 1951): Nautilus grundensis Trenkner, 1868, Viséan, Harz Mountains; Coloceras globatum Hyatt, 1894, Viséan, Belgium; Coloceras European Journal of Taxonomy 1018: 1–113 (2025) 82 hyatti Miller, Dunbar & Condra, 1933, Viséan, Belgium; Liroceras occlusor Schmidt, 1951, Viséan, Harz Mountains; Liroceras schaelkense Schmidt, 1951, Viséan, Rhenish Mountains. North Africa (Korn & Klug 2023): Liroceras karaouii Korn & Klug, 2023, Viséan, Anti-Atlas; Liroceras vermis Korn & Klug, 2023, Serpukhovian, Anti-Atlas. Western Russia (Eichwald 1857; Shimansky 1967): Nautilus excentricus Eichwald, 1857, Serpukhovian, Western Russia; Liroceras fornicatum Shimansky, 1967, Serpukhovian, Western Russia; Liroceras devjatovense Shimansky, 1967, Moscovian, Moscow Basin. Urals (Shimansky 1967): Liroceras praelunense Shimansky, 1967, Viséan, North Urals; Liroceras ruzhencevi Shimansky, 1967, Serpukhovian, South Urals. North China (Ruan & Zhou 1987): Liroceras reniforme Ruan & Zhou, 1987, Bashkirian, Ningxia. Included Permian species North America (Hyatt 1893): Coloceras globulare Hyatt, 1893, Artinskian, Texas. Central and Southern Europe (Gemmellaro 1889; Prinoth & Posenato 2007): Endolobus salomonensis Gemmellaro, 1889, Wordian, Sicily; Liroceras gardenense Prinoth & Posenato, 2007, Changhsingian, Dolomites. Western Russia, Urals (Yakovlev 1899; Kruglov 1928; Barskov et al. 2014; Leonova & Shchedukhin 2020): Asymptoceras korulkense Yakovlev, 1899, Sakmarian, South Urals; Coloceras (?) sarvaensis Kruglov, 1928, Sakmarian (?), South Urals; Coloceras abichi var. tastubense Kruglov, 1928, Sakmarian (?), South Urals; Liroceras volgense Barskov & Shilovsky, 2014, Roadian, Western Russia; Liroceras shakhtauense Leonova & Shchedukhin, 2020, Asselian or Sakmarian, South Urals. NW Iran (this paper): Liroceras choopani sp. nov., Wuchiapingian. Central Iran (Korn & Hairapetian in press): new species P to be described by Korn & Hairapetian (in press), Wuchiapingian. Pakistan (Reed 1944): Liroceras bakhense Reed, 1944, Wuchiapingian, Salt Range. South China (Chao 1940, 1954; Xu 1977; Zhao et al. 1978; Liang 1984; Wu & Kuang 1992): Coloceras sinense Chao, 1940, Kungurian, Hunan; Peripetoceras hsueyuechiani Chao, 1954, Kungurian, Hunan; Liroceras orientale Chao, 1954, Kungurian, Hunan; Ephippioceras hunanense Chao, 1954, Kungurian, Hunan; Liroceras didmyoaurise Xu, 1977, Kungurian, Hunan; Liroceras meishanense Zhao, Liang & Zheng, 1978, Changhsingian, Zhejiang; Liroceras chenxianense Liang, 1984, Changhsingian, Hunan; Liroceras lichuanense Wu & Kuang, 1992, Changhsingian, Hubei. Indopacific (Haniel 1915): Nautilus Molengraaffi Haniel, 1915, Wuchiapingian, Timor. Madagascar (Vaillant-Couturier Treat 1933): Nautilus waterloti Vaillant-Couturier Treat, 1933, Wuchiapingian. Remarks The genus Liroceras was introduced by Teichert (1940) for those Carboniferous and Permian nautiloids that were previously mostly included in the genus Coloceras Hyatt, 1893. The name Coloceras had already been used by Taschenberg (1882) as a subgenus for recent Mallophaga. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 83 Liroceras has a stratigraphic range from the Viséan to the Changhsingian and is represented by species at almost all stages of this long interval. At the same time, Liroceras is geographically widespread, both in the Carboniferous and in the Permian. Liroceras is also known from different facies areas; Early Carboniferous species are known from shallower and deeper areas of the shelf. In the Late Permian, the genus was more common in the shallower areas of the sea, as suggested by the occurrences at Julfa, where it co-occurs with the morphologically similar and closely related genus Permonautilus. Liroceras choopani sp. nov. urn:lsid:zoobank.org:act:47A75088-13DD-4168-B8B0-07AEAA7A93E5 Figs 41–42; Table 24 Liroceras sp. indet. – Teichert et al. 1973: 401, pl. 8 fig. 9. Liroceras sp. – Gliwa et al. 2020: text-fig. 17e. Diagnosis Species of Liroceras with thinly globular, involute conch (ww/dm ~ 0.85–0.90; uw/dm ~ 0.05), moderately depressed whorl profile (ww/wh ~ 1.50–1.65) and high to very high coiling rate (WER ~ 2.00–2.35) between a conch diameter of 75 and 135 mm. Whorl profile with broadly arched venter and flanks, broadly rounded umbilical margin and convex umbilical wall and deep imprint zone (IZR ~ 0.40). Ornament with coarse, convex growth lines and coarse spiral lines. Suture line nearly straight. Etymology Named after Hadi Choopan, former Iranian Mr Olympia, referring to the most robust nautiloid found in the Julfa assemblage. Type material Holotype IRAN – East Azerbaijan • Zal; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; illustrated in Fig. 41A; MB.C.32067. Paratypes IRAN – East Azerbaijan • 1 specimen; same data as for holotype; illustrated in Fig. 41B–C; MB.C.32068 • 1 specimen; Ali Bashi 4; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2018; Ghaderi leg.; MB.C.32069 • 1 specimen; same data as for holotype; 2010; Korn et al. leg.; MB.C.32070 • 1 specimen; Ali Bashi; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); illustrated in Fig. 42; GLM#GH1005. – West Azerbaijan • 1 specimen; Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2013; Korn et al. leg.; illustrated in Fig. 41D–E; MB.C.29350. Description Holotype MB.C.32067 is an incomplete specimen with a conch diameter of approximately 133 mm (Fig. 41A). The proportions of the conch can only be estimated; the specimen was apparently globular Fig. 41 (opposite page). Liroceras choopani sp. nov. from the Araxoceras Beds of the Julfa Formation. A. Holotype MB.C.32067 (Ghaderi 2018 Coll.) from Zal, lateral and apertural views with dorsal view reconstruction. B. Paratype MB.C.32068 (Ghaderi 2018 Coll.) from Zal, cross section. C. The same specimen, suture line at ww = 84.5 mm. D. Paratype MB.C.29350 (Korn et al. 2013 Coll.) from Aras Valley, lateral and ventral views. E. The same specimen; reconstruction of apertural view. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 84 KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 85 (ww/dm ~ 0.90) with an almost closed umbilicus and a moderately high coiling rate (WER ~ 2.10). The whorl profile is semilunate and widest at the broadly rounded umbilical margin; it has a deep imprint zone (IZR ~ 0.40). Flanks and venter are continuously rounded to form a hemisphere. Shell remains show very coarse growth lines, which extend with a convex arch across the flanks and form a deep, subangular ventral sinus. A second element of ornament are coarse spiral lines, which are almost of the same strength as the growth lines, together forming a reticulated ornament. Paratype MB.C.32068 with a conch diameter of 112 mm was sectioned for studying the conch ontogeny (Fig. 41B), but the inner whorls are recrystallised or deformed. However, it shows an almost isometric ontogeny between 48 and 113 mm diameter. During this interval of one and a half volutions, the conch changes from thickly pachyconic (ww/dm = 0.82 at 48.5 mm dm) to thinly globular (ww/dm = 0.87 at 113 mm dm). The umbilicus is almost closed (uw/dm decreases from 0.06 to 0.02). The suture line of the specimen is almost straight with a very shallow external lobe and an also very shallow lateral lobe (Fig. 41C). The smaller fragmentary paratype MB.C.29350 with a conch diameter of 50 mm had to be reconstructed for its conch proportions (Fig. 41E), but it is evident that it is slightly slenderer than the two large specimens (ww/dm ~ 0.78). This specimen is preserved with shell material that shows rhythmically reinforced growth lines extending with a broadly rounded lateral projection and a deep subangular ventral sinus. Remarks Liroceras choopani sp. nov. is one of the few species in the species-rich genus with an almost closed umbilicus and is therefore easy to distinguish from many other species, which usually have a uw/ dm ratio of about 0.20. Among the Middle and Late Permian species with a nearly closed umbilicus, Fig. 42. Liroceras choopani sp. nov., paratype GLM#GH1005 from the Araxoceras Beds of the Julfa Formation from Julfa, dorsal and lateral views. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 86 L. meishanense and L. hsuechuechiani (Chao, 1854) are slender (ww/dm ~ 0.57 and 0.67, respectively), L. gardenense and L. didmyoaurise are stouter (ww/dm > 0.90) at comparable conch diameters. Large specimens of L. choopani sp. nov. have a coarser ornamentation consisting of growth lines and spiral lines. Such an adult ornament is not known from other species, although only a few species with a conch diameter of over 100 mm are known. Genus Celeroliroceras gen. nov. urn:lsid:zoobank.org:act:DDB55D63-9584-47C5-B8B4-BD69879FDB4F New genus G – Korn 2025: 66. Type species Celeroliroceras celere gen. et sp. nov. Diagnosis Genus of the family Liroceratidae with globular, involute or subinvolute conch. The conch is rapidly increasing in height with an extraordinarily high coiling rate (WER higher than 3.50). Whorls very weakly embracing with nearly circular profile. Adult ornament very weak. Septa without inflexions, slightly concave. Suture line simple, nearly straight to straight with shallow lobes. Etymology Combination of the Latin ‘celere’ (adjective, n.) = ‘fast’ and Liroceras; because of the conch geometry with the extraordinarily high coiling rate. Included species NW Iran (this paper): Celeroliroceras celere gen. et sp. nov., Wuchiapingian. Remarks Celeroliroceras gen. nov. is a genus that differs from Liroceras in its extraordinarily high coiling rate of the conch. The type species has a whorl expansion rate of over 3.60, a value far above that of most species of Liroceras. The whorl expansion rate of liroceratids is usually around 2.50. The new species is therefore placed in its own genus. The conch of Celeroliroceras gen. nov. is very reminiscent of that of the genus Solenochilus Meek & Worthen, 1870, which is also characterised by an exceptionally high whorl expansion rate. However, the position of the siphuncle, central in Celeroliroceras and marginally ventral in Solenochilus, indicates that both genera belong to phylogenetically distant evolutionary lineages. Table 24. Conch dimensions (in mm) and ratios of Liroceras choopani sp. nov.; reconstructed dimensions and ratios in italics. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32067 133.0 118.0 71.0 7.0 41.0 0.89 1.66 0.05 2.09 0.42 MB.C.32068 113.0 98.2 66.5 2.5 38.8 0.87 1.48 0.02 2.32 0.42 MB.C.32068 74.2 66.4 44.0 3.3 25.7 0.89 1.51 0.04 2.34 0.42 MB.C.32068 48.5 39.7 26.9 2.9 – 0.82 1.48 0.06 – – MB.C.29350 49.5 38.5 28.0 1.0 17.0 0.78 1.38 0.02 2.32 0.39 KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 87 Celeroliroceras celere gen. et sp. nov. urn:lsid:zoobank.org:act:B1A2F8FC-0603-4F60-A7BA-5E5735C44FF2 Fig. 43; Table 25 Liroceras sp. – Gliwa et al. 2020: text-fig. 17g. Diagnosis Species of Celeroliroceras gen. nov. with thinly globular, subinvolute to involute conch (ww/dm ~ 0.85–0.90; uw/dm ~ 0.15), weakly to moderately depressed whorl profile (ww/wh ~ 1.40–1.60) and extraordinarily high coiling rate (WER ~ 3.60) between a conch diameter of 30 and 60 mm. Whorl profile with broadly arched venter and flanks, broadly rounded umbilical margin and convex umbilical wall and small imprint zone (IZR ~ 0.15). Shell surface smooths. Suture line nearly straight. Etymology From the Latin ‘celere’ (adjective, n.) = ‘fast’; because of the conch geometry with the extraordinarily high coiling rate. Type material Holotype IRAN – West Azerbaijan • Aras Valley; Araxoceras Beds of the Julfa Formation (early Wuchiapingian); 2011; Korn et al. leg.; illustrated in Fig. 43; MB.C.29352. Description Holotype MB.C.29352 is fully septate with a conch diameter of 57 mm (Fig. 43A). It is slightly deformed but relatively well preserved, allowing the study of conch geometry, suture line and, with limitations, ornamentation. The remarkable conch geometry is mainly caused by the extraordinarily high coiling rate (WER = 3.60). The conch is globular and involute (ww/dm = 0.88; uw/dm = 0.14) and the ww/wh ration amounts 1.60. The whorl profile is crescent-shaped with a convex umbilical wall and a rounded umbilical margin from which the flanks converge strongly towards the broadly rounded venter (Fig. 43B). The Fig. 43. Celeroliroceras celere gen. et sp. nov., holotype MB.C.29352 (Korn et al. 2011 Coll.) from the Araxoceras Beds of the Julfa Formation at Aras Valley. A. Lateral and apertural views. B. Reconstruction of apertural view. C. Suture line at dm = 57.0 mm, ww = 46.5 mm, wh = 27.2 mm. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 88 whorl overlap zone is very small (IZR = 0.15). It appears that the whorl width increases faster than the whorl height on the last volution; the ww/wh ratio increases from 1.43 to 1.60 during the last half volution. There are some shell remains attached to the phragmocone; these are almost smooth with no traces of ornamentation. The suture line is almost straight, but has a very flat and very wide external lobe (Fig. 43C). Remarks Celeroliroceras celere gen. et sp. nov. is very different from all other Late Permian nautiloids. It is clearly separable from the co-occurring Liroceras choopani sp. nov. by its extraordinarily high coiling rate (WER = 3.60 in contrast to 2.30 in L. choopani) and the much smaller whorl overlap rate. Celeroliroceras sp. Fig. 44; Table 26 Material examined IRAN – West Azerbaijan • 1 specimen; Aras Valley; Vedioceras Beds of the Julfa Formation (late Wuchiapingian); 2011; Korn et al. leg.; illustrated in Fig. 44; MB.C.32071. Description Specimen MB.C.32071 is a fragment of a juvenile specimen with a conch diameter of 35 mm (Fig. 44A). It shows a thickly pachyconic, involute conch (ww/dm = 0.82; uw/dm = 0.12) with a weakly depressed oval whorl profile (ww/wh = 1.43). The coiling rate is extraordinarily high (WER = 3.35). Remarks The specimen is too poorly preserved for a more detailed description. Because of the conch geometry and the extraordinarily high coiling rate, it probably belongs to Celeroliroceras gen. nov. Table 25. Conch dimensions (in mm) and ratios of Celeroliroceras celere gen. et sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.29352 57.1 50.5 31.6 7.8 27.0 0.88 1.60 0.14 3.60 0.15 MB.C.29352 32.6 28.5 19.9 5.7 – 0.87 1.43 0.17 – – Fig. 44. Celeroliroceras sp., specimen MB.C.32071 (Korn et al. 2011 Coll.) from the Vedioceras Beds of the Julfa Formation at Aras Valley. A. Ventral and lateral views. B. Reconstruction of apertural view. C. Suture line at dm = 24.5 mm, ww = 22.0 mm, wh = 13.2 mm. Scale bar units = 1 mm. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 89 uw/dm = 0.14). The whorl profile suffered from deformation, but the symmetry of the specimen suggests that the venter was probably concave near the terminal aperture. On both sides of the specimen there are remnants of lateral umbilical processes, hemispherical in section and about 22 mm in diameter. As they are broken it is impossible to determine their original length. The shell remains appear smooth but show traces of fine growth lines, which are almost straight in their course across the flank. The septa are crowded at the end of the phragmocone at a conch diameter of about 94 mm; the suture line has an almost straight course (Fig. 46C). The smaller specimens show that intraspecific variation in conch geometry is rather limited. Specimen MB.C.32075 may serve as a characteristic example (Fig. 47A–B). It is a fragment with a conch diameter of 56 mm and has a globular and subinvolute shape (ww/dm = 0.88; uw/dm = 0.19) with a moderately depressed whorl profile (ww/wh = 1.95) and a very high coiling rate (WER = 2.26). However, the specimen differs from the others in that it is the only individual to show remnants of a coarse ornament, visible only in a small area as impressions on the internal mould. It appears that the specimen has rather coarse growth lines, spaced about one millimetre apart, with a rather shallow and wide sinus extending across the venter. The suture line is almost straight (Fig. 47C). Specimens MB.C.29351 (34 mm dm; Fig. 47G) and MB.C.32077 (51 mm dm; Fig. 47F) give an impression of the ontogenetic development of the conch, in which no major changes can be seen. The conch is thinly globular (ww/dm = 0.95 and 0.88 respectively) and the whorl width is approximately twice the whorl height. Fig. 48. Permonautilus abichi (Kruglov, 1928) from the Araxoceras Beds of the Julfa Formation of Ali Bashi. A. Specimen GLM#GH1003, lateral and ventral views. B. Specimen GLM#GH1001, ventral and dorsal views. Scale bar units = 1 mm. Table 28. Conch dimensions (in mm) and ratios of Permonautilus abichi (Kruglov, 1928). Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32074 134.0 99.0 64.5 19.0 39.5 0.74 1.53 0.14 2.01 0.39 MB.C.32074 94.5 74.0 43.0 – – 0.78 1.72 – – – MB.C.32088 84.5 66.0 40.5 16.5 28.0 0.78 1.63 0.20 2.24 0.31 MB.C.32076 78.0 58.7 34.3 12.0 27.0 0.75 1.71 0.15 2.34 0.21 MB.C.32075 56.4 49.8 25.6 10.7 18.9 0.88 1.95 0.19 2.26 0.26 MB.C.32080 56.0 46.1 25.0 10.5 19.5 0.82 1.84 0.19 2.35 0.22 MB.C.32077 50.5 44.5 22.0 10.8 17.0 0.88 2.02 0.21 2.27 0.23 MB.C.29351 33.6 32.0 16.5 – – 0.95 1.94 – – – MB.C.32091 28.2 31.5 12.9 6.3 10.6 1.12 2.44 0.22 2.57 0.18 European Journal of Taxonomy 1018: 1–113 (2025) 96 Specimen MB.C.32076 (78 mm dm; Fig. 47D) has a similar morphology but is slenderer (ww/dm = 0.75). In this specimen the septa of two consecutive whorls can be seen. They show a displaced siphuncle with a diameter of 0.15 of the aperture height. A characteristic visible in nearly all the specimens is the presence of a midventral longitudinal line on the internal mould, being produced by a thin internal groove in the shell. The character was already figured by Abich (1878: pl. 3 fig. 3) and described under the species “Nautilus concavus”. Remarks Abich (1878) described the following species, which may belong to Permonautilus abichi: • “Nautilus excentricus Eichwald”. – The fully chambered specimen with a conch diameter of 30 mm described and illustrated by Abich (1878: pl. 1 fig. 4) has an almost spherical shape with a rather wide umbilicus (uw/dm = 0.40). Flanks and venter are broadly rounded. The suture line is almost straight but forms a shallow lobe on the venter. • “Nautilus propinquus, nov. form.”. – Abich (1878: pl. 3 fig. 6) described and illustrated only a small, chambered specimen with a conch diameter of about 20 mm. It shows a narrowly umbilicate conch with a clear umbilical margin and apparently broadly rounded flank and venter. The suture line is almost straight. This specimen is probably not suitable to characterise a species. • “Nautilus concavus Sowerby”. – Abich (1878: pl. 3 figs 3–4) illustrated two fragments with about 50 mm and a conch diameter of 40 mm, respectively. The smaller specimen is better preserved and shows the whorl profile of an inner whorl. At a diameter of 16 mm, the conch is globular (ww/ dm = 1.03) with a very narrow umbilicus (uw/dm = 0.10) and a depressed whorl profile (ww/wh = 1.90). The whorl profile shows a shallow dorsal inflexion. Already von Arthaber (1900) suggested that it is not clear whether the three species described by Abich (1878), “Nautilus excentricus”, “Nautilus propinquus” and “Nautilus concavus”, belong to one single species. He synonymised these three species with the Middle Permian Nautilus cornutus Golovkinsky, 1869 from the Volga Basin of Russia. In a revision of this occurrence, Kruglov (1928) discussed “Nautilus excentricus” of Abich and gave it the new name “Coloceras Abichi”. Kruglov (1933) later placed this species in his new genus Permonautilus. Shimansky (1962c) then used this species to found the new subgenus Permonautilus (Alexandronautilus), which should be distinguished from the nominal genus by the presence of thin transverse ribs. In a later account (Shimansky 1965a), however, he did not use this anymore. Barskov et al. (2014), when revising the Middle Permian cephalopods of the VolgaUral region, also did not use the subgenus. Instead, they separated the genus Permonautilus and their new genus Nemdoceras from the Liroceratidae, for which they introduced the new family Permonautilidae that is characterised by their spiny umbilical projections. The presence of umbilical shell processes in the material from Julfa was already suggested by von Arthaber (1900: 212), but the specimen he cited (von Arthaber 1900: pl. 18 fig. 1) is probably too small to have developed such projections. The large specimen MB.C.32074 now allows us to clearly assign the material to Permonautilus. Our material differs from the species from the Volga-Ural region mainly by the narrower umbilicus (uw/dm is about 0.15, in contrast to 0.20–0.30 in the species from the Volga). Teichert & Kummel (1973) did not list Permonautilus among their collection from Ali Bashi, although Shimansky (1965a) mentioned 28 specimens in his collection from the neighbouring sites north of the Aras River, meaning that it is a commonly occurring genus. It is most likely that the material attributed to Liroceras sp. indet. by Teichert & Kummel (1973) in fact belongs to Permonautilus. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 97 Family Julfanautilidae fam. nov. urn:lsid:zoobank.org:act:9B985B5C-9C06-4713-A6C1-763F6D4B4AA4 new family – Korn 2025: 65, 69, fig. 35. Type genus Julfanautilus gen. nov. Diagnosis Family of the superfamily Liroceratoidea with a usually pachyconic, subinvolute to involute conch. Whorl profile in the adult stage usually more or less strongly depressed; flanks and venter usually separated by distinct ventrolateral shoulder, venter flattened or concave. Umbilical margin subangular or angular; umbilical wall steep, flattened. Ornament usually consisting of fine growth lines. Septum simple in shape, concavely domed; suture line with shallow lobes on venter and flank. Etymology Named after the type genus Julfanautilus gen. nov. Included genera Julfanautilus gen. nov. (Permian); new genus E to be described by Korn & Hairapetian (in press) (Permian); new genus F to be described by Korn & Hairapetian (in press) (Permian). Remarks The family Julfanautilidae fam. nov. is characterised by a combination of characters not found in any other family of Palaeozoic nautilids. This is the combination of a rather stout conch with a very pronounced umbilical margin and also a sometimes pronounced ventrolateral shoulder. While the first character suggests a placement in the superfamily Liroceratoidea, the second and third characters show a closer morphological relationship to the superfamilies Pleuronautiloidea and Grypoceratoidea. Unfortunately, the early ontogenetic development of the conch in the species of the Julfanautilidae is not known. However, the material shows that the pronounced umbilical margin is present early in ontogeny and that this feature can therefore be considered apomorphic, whereas the ventrolateral shoulder does not assume a subangular shape until a late ontogenetic stage, if at all. Therefore, these forms are included here as a new family of the superfamily Liroceratoidea. Genus Julfanautilus gen. nov. urn:lsid:zoobank.org:act:D5ED78D7-D4E4-43D0-B9E9-193D3554B4AB new genus H – Korn 2025: 69, fig. 35. Type species Julfanautilus ashourii gen. et sp. nov. Diagnosis Genus of the family Julfanautilidae fam. nov. with thinly pachyconic, involute or subinvolute conch. Conch rapidly increasing in height with an extremely or extraordinarily high coiling rate (WER higher than 2.50). Whorls weakly embracing, whorl profile weakly depressed. Venter weakly concave, umbilical margin usually narrowly rounded, umbilical wall flat and steep. Adult ornament with extremely fine growth lines. Septa without inflexions, slightly concave. Suture line simple with shallow external lobe and broadly rounded lateral lobe. Etymology Combination of the name of the type region and Nautilus. European Journal of Taxonomy 1018: 1–113 (2025) 98 Included species NW Iran (this paper): Julfanautilus ashourii gen. et sp. nov., Wuchiapingian; Julfanautilus hairapetiani gen. et sp. nov., Wuchiapingian. Remarks Julfanautilus gen. nov. has some similarities to Coelogasteroceras, particularly in the pachyconic conch and the shape of the venter with the shallow median groove. However, the specimens of Coelogasteroceras have a rounded umbilical margin, which differs from the angulate or subangular umbilical margin in Julfanautilus. Since the shape of the umbilical margin is very stable in numerous Carboniferous and Permian nautiloids, this is also assumed for Julfanautilus. The similarity in venter shape between Coelogasteroceras and Julfanautilus is therefore interpreted as a case of convergent morphological evolution. Julfanautilus ashourii gen. et sp. nov. urn:lsid:zoobank.org:act:B2ABF480-DEB4-43BA-97D1-80FFF3C2B11B Fig. 49; Table 29 New genus H, new species – Korn 2025: 70, fig. 35. Diagnosis Species of Julfanautilus gen. nov. with a thinly pachyconic, subinvolute conch (ww/dm ~ 0.65; uw/dm ~ 0.25), weakly depressed whorl profile (ww/wh ~ 1.30) and extraordinarily high coiling rate (WER ~ 3.10) at a conch diameter of 80 mm. Whorl profile with a weakly concave venter, a subangular Fig. 49. Julfanautilus ashourii gen. et sp. nov., holotype MB.C.32095 (Korn et al. 2011 Coll.) from the Vedioceras Beds of the Julfa Formation at Aras Valley. A. Lateral and apertural views. B. Reconstruction of apertural view. C. Suture line at dm = 76 mm, ww = 55 mm, wh = 42 mm.Scale bar units = 1 mm. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 99 ventrolateral shoulder, flatly convex and weakly convergent flanks, a narrowly rounded umbilical margin, a steep and flattened umbilical wall and a small imprint zone (IZR ~ 0.10). Suture line with a broadly rounded and shallow external lobe and a broadly rounded lateral lobe. Etymology Named after Ali Reza Ashouri (Mashhad), to acknowledge his support in the project. Type material Holotype IRAN – West Azerbaijan • Aras Valley; Vedioceras Beds of the Julfa Formation (late Wuchiapingian); 2011; Korn et al. leg.; illustrated in Fig. 49; MB.C.32095. Description Holotype MB.C.32095 is a fully chambered conch with a diameter of 87 mm (Fig. 49A); suggesting a total diameter of approximately 150 mm including the body chamber. It is thinly pachyconic (ww/ dm = 0.62) and subinvolute (uw/dm = 0.24) with an extraordinarily high coiling rate (WER = 3.10). There is almost no whorl overlap. The whorls are widest at the pronounced, narrowly rounded umbilical margin; the umbilical wall is steep and flattened. The flanks converge towards the pronounced ventrolateral shoulder, which separates them from the broad and weakly flattened venter. The midventer possesses a very shallow longitudinal depression. Shell remains are not preserved. The suture line has a shallow, broadly rounded external lobe and a broad and shallow lateral lobe of equal depth (Fig. 49C). Remarks Julfanautilus ashourii gen. et sp. nov. differs from J. hairapetiani gen. et sp. nov. in the open umbilicus, which is closed in J. hairapetiani and in the higher coiling rate (WER ~ 3.10 in J. ashourii but only ~ 2.60 in J. hairapetiani). Julfanautilus hairapetiani gen. et sp. nov. urn:lsid:zoobank.org:act:AF3620C5-D1F3-401D-8B29-8BB929B610E2 Fig. 50; Table 30 Diagnosis Species of Julfanautilus gen. nov. with a thinly pachyconic, involute conch (ww/dm ~ 0.65; uw/dm ~ 0.05), weakly depressed whorl profile (ww/wh ~ 1.15) and extremely high coiling rate (WER ~ 2.60) at a conch diameter of 80 mm. Whorl profile with a weakly concave venter, a pronounced ventrolateral shoulder, flatly convex and moderately convergent flanks, a narrowly rounded umbilical margin, a steep and flattened umbilical wall and a moderately deep imprint zone (IZR ~ 0.30). Suture line with broadly rounded and shallow external lobe and broadly rounded lateral lobe. Etymology Named after Vachik Hairapetian (Isfahan), to acknowledge his support in the research project on the Permian–Triassic boundary. Type material Holotype IRAN – East Azerbaijan • Ali Bashi 4; Vedioceras Beds of the Julfa Formation (late Wuchiapingian); 2010; Korn et al. leg.; illustrated in Fig. 50; MB.C.32096. Table 29. Conch dimensions (in mm) and ratios of the holotype of Julfanautilus ashourii gen. et sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32095 87.4 54.4 42.2 21.0 37.8 0.62 1.29 0.24 3.10 0.10 European Journal of Taxonomy 1018: 1–113 (2025) 100 Description Holotype MB.C.32096 has a conch diameter of 83 mm and is fully chambered (Fig. 50A). It is thinly pachyconic (ww/dm = 0.63) with an almost closed umbilicus and an extremely high coiling rate (WER = 2.58). The whorl profile shows that the preceding whorl is strongly embraced (IZR = 0.31). The conch is widest at the pronounced, narrowly rounded umbilical margin, from where a steep, broadly rounded umbilical wall approaches the umbilical seam. The flanks converge towards the broadly rounded ventrolateral shoulders; the venter is broadly rounded with a shallow and wide median depression. Shell remains are not preserved. The suture line has a shallow, broadly rounded external lobe and a much larger and broadly rounded lateral lobe, which is twice as deep as the external lobe (Fig. 50C). Remarks Julfanautilus hairapetiani gen. et sp. nov. differs from J. ashourii gen. et sp. nov. in the closed umbilicus (uw/dm = 0.24 in J. ashourii) and the lower coiling rate (WER ~ 2.60 in J. hairapetiani but ~ 3.10 in J. ashourii). Fig. 50. Julfanautilus hairapetiani gen. et sp. nov., holotype MB.C.32096 (Korn et al. 2010 Coll.) from the Vedioceras Beds of the Julfa Formation at Ali Bashi 4. A. Lateral and apertural views. B. Reconstruction of apertural view. C. Suture line at dm = 70.5 mm, ww = 52.5 mm, wh = 44.5 mm. Scale bar units = 1 mm. Table 30. Conch dimensions (in mm) and ratios of the holotype of Julfanautilus hairapetiani gen. et sp. nov. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32096 83.2 52.2 45.2 2.5 31.4 0.63 1.15 0.03 2.58 0.31 KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 101 New genus F Korn & Hairapetian (in press) Type species New species R to be described by Korn & Hairapetian (in press); original designation. Diagnosis Genus of the family Julfanautilidae fam. nov. with discoidal, involute conch. The conch is rapidly increasing in height with a very high to extremely high coiling rate (WER usually higher than 2.50). Whorls moderately strongly embracing, their profile ranges from compressed to weakly depressed. Adult ornament with extremely fine growth lines. Septa without inflexions, slightly concave. Suture line simple, nearly straight to straight with a low external saddle, broadly rounded internal lobe. The siphuncle has a dorsocentral position (from Korn & Hairapetian in press). Included species Central Iran (Korn & Hairapetian in press): new species R to be described by Korn & Hairapetian (in press), Wuchiapingian. Remarks Korn & Hairapetian (in press) compared the new genus with other similar genera; in terms of conch morphology, the new genus shows some similarities to the genera Julfanautilus gen. nov. and the new genus E to be described by Korn & Hairapetian (in press). This is particularly true for the shape of the whorl profile with slightly flattened, converging flanks and the slightly flattened umbilical wall. However, the other two genera show a much higher coiling rate (WER above 3.00) than the new genus (WER around 2.50) and a much more pronounced subangular to angular umbilical margin. New genus F Korn & Hairapetian (in press) sp. Fig. 51; Table 31 Material examined IRAN – West Azerbaijan • 1 specimen; Aras Valley; Paratirolites Limestone of the Ali Bashi Formation (late Changhsingian); 2011; Korn et al. leg.; illustrated in Fig. 51; MB.C.32097. Fig. 51. New genus F Korn & Hairapetian (in press) sp., specimen MB.C.32097 (Korn et al. 2011 Coll.) from the Paratirolites Limestone of Ali Bashi. A. Reconstruction of apertural view. B. Lateral and ventral views. Scale bar units = 1 mm. European Journal of Taxonomy 1018: 1–113 (2025) 102 Description Specimen MB.C.32097 is the fragment of a half whorl, which belongs entirely to the body chamber (Fig. 51A). The conch has a diameter of about 53 mm and is discoidal and involute (ww/dm = 0.45; uw/ dm = 0.06). Flanks and venters are rounded. The surface of the internal mould appears to be completely smooth. Remarks The single specimen from the Paratirolites Limestone is too poorly preserved to be assigned to a specific species. Suborder indet. Genus and species indet. Fig. 52 Material examined IRAN – East Azerbaijan • 1 specimen; Ali Bashi 4; lower Julfa Formation (early Wuchiapingian); 2013; Korn et al. leg.; illustrated in Fig. 52; MB.C.32098. Description Specimen MB.C.32098 is the fragment of a quarter whorl, which belongs entirely to the phragmocone (Fig. 52A). The curvature of the whorl suggests that the conch was subinvolute. The whorl profile has a height of 24.5 mm and a width of 31.6 mm and is depressed elliptical without an umbilical margin or a ventrolateral venter; the whorl overlaps the preceding to a very low degree (Fig. 52B). The septa are arranged in short distances of less tat 10 degrees. The suture line is nearly straight (Fig. 52C). Remarks The single specimen does not allow precise identification due to the fragmentary preservation and the small number of characteristic features. However, because of the unusual combination of characters, such as the weakly depressed elliptical whorl profile, the rather narrow umbilicus and especially the very dense septa, it is briefly described and illustrated here. Table 31. Reconstructed conch dimensions (in mm) and ratios of the new genus F Korn & Hairapetian (in press) sp. Nr. dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.32097 53 24 29 323 0.45 0.83 0.06 3.12 0.21 Fig. 52. gen. indet. sp., specimen MB.C.32098 (Korn et al. 2013 Coll.) from the Araxoceras Beds of the Julfa Formation at Ali Bashi 4. A. Reconstruction of apertural view. B. Lateral and ventral views. C. Suture line, at wh = 24 mm. Scale bar units = 1 mm. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 103 Discussion The Late Permian Julfa and Ali Bashi formations of sections near Julfa (NW Iran) have yielded diverse nautiloid assemblages. These species belong to 20 genera, eight of which are new: Fididomatoceras gen. nov., Azarinautilus gen. nov., Serometacoceras gen. nov., Alibashinautilus gen. nov., Tardunautilus gen. nov., Corotainoceras gen. nov., Celeroliroceras gen. nov., Julfanautilus gen. nov. Based on new material, a total of 30 species is described, of which 24 are new. The material comes from four stratigraphic units, in ascending order: Araxoceras Beds (early Wuchiapingian) – 19 species and one in open nomenclature: Domatoceras elegantulum sp. nov., Domatoceras multituberculatum sp. nov., Domatoceras convergens (Abich, 1878), Permodomatoceras hamdii sp. nov., Fididomatoceras gracile (Shimansky, 1965) gen. et comb. nov., Fididomatoceras intracostatum gen. et sp. nov., Azarinautilus nahidae gen. et sp. nov., Aifinautilus hebes sp. nov., Serometacoceras dorsoarmatum (Abich, 1878) gen. et comb. nov., Serometacoceras dorashamense (Shimansky, 1965) gen. et comb. nov., Serometacoceras verae (von Arthaber, 1900) gen. et comb. nov., Serometacoceras cingulum gen. et sp. nov., Serometacoceras inflatum gen. et sp. nov., Alibashinautilus vetus gen. et sp. nov., Alibashinautilus sp., Tardunautilus minor gen. et sp. nov., Corotainoceras inerme gen. et sp. nov., Liroceras choopani sp. nov., Celeroliroceras celere gen. et sp. nov., Permonautilus abichi (Kruglov, 1928). Vedioceras Beds (late Wuchiapingian) – six species: Serometacoceras parvituberculatum gen. et sp. nov., Tainoceras admonens sp. nov., Tainoceras latecostatum sp. nov., Peripetoceras parum sp. nov., Julfanautilus ashourii gen. et sp. nov., Julfanautilus hairapetiani gen. et sp. nov. Dzhulfites Beds (early Changhsingian) – three identified species and three in open nomenclature: Tainoceras unitum sp. nov., Tirolonautilus sp. 2, Serometacoceras arasense gen. et sp. nov., new genus C to be described by Korn & Hairapetian (in press) sp., Tardunautilus nimius gen. et sp. nov., new genus A to be described by Korn & Hairapetian (in press) sp. Paratirolites Limestone (late Changhsingian) – two identified species and two in open nomenclature: Alibashinautilus ambiguus gen. et sp. nov., Tainionautilus deinceps sp. nov., Tirolonautilus sp. 1, Baghuknautilus sp. With 30 species, the assemblage from the area around Julfa is one of the most diverse Late Permian occurrences of coiled nautiloids. With 25 Wuchiapingian species alone, it is the most species-rich assemblage for this interval. The succession of nautiloids in the Julfa sections shows a significant decline in both the number of specimens and the number of species above the lower Araxoceras Beds. This decline is almost diametrically opposed to the abundance and diversity of ammonoids, which are particularly common and diverse in the Paratirolites Limestone (Korn et al. 2016). The decline of nautiloids is accompanied by a deepening of the habitat (Leda et al. 2014; Gliwa et al. 2020); the nautiloids in the lower Araxoceras Beds occur in association with species-rich brachiopod assemblages (Ghaderi et al. 2014). A comparison of the nautiloids from Julfa with the assemblages from other regions with fossil-bearing Late Permian sedimentary rocks is difficult for several reasons. (1) A precise stratigraphic correlation is often difficult or impossible. (2) Facies differences between the various occurrences make it difficult to compare similar positions in the sedimentation basins and thus the habitats of the nautiloids. (3) Latitudinal differences and thus different seawater temperatures could have influenced the nautiloid associations. European Journal of Taxonomy 1018: 1–113 (2025) 104 Time-equivalent associations of nautiloids from central Iran (Korn & Hairapetian in press) show similar compositions at the family and genus level, but there are probably no common species from both regions. Although the two regions are separated by only about 1000 kilometres and have very similar sedimentary sequences (Leda et al. 2014; Gliwa et al. 2020; Korn et al. 2021; Heuer et al. 2022), there are clear differences in the nautiloid communities. The genus Serometacoceras gen. nov., which is wellrepresented in the Julfa sections, is very rare in the central Iranian sections, and the opposite is true for the new genera A and C to be described by Korn & Hairapetian (in press). Acknowledgements We are indebted to the Aras Free Zone Office (Julfa) for their support of the field sessions. We thank Lucyna Leda (Zamarte) and Nahideh Ghanizadeh Tabrizi (Tabriz) for assistance during the field work and for contributing numerous specimens, Markus Brinkmann (Berlin) for preparation of the specimens and Jenny Huang and Jamie Lembke (Berlin) for taking photographs. For access to the specimens in the Golfaraj Ecomuseum, we thank Eskandar Ebdali (Julfa). We acknowledge the reviews of an earlier version by Herwig Prinoth (St Ulrich) and an anonymous reviewer. We also acknowledge the careful editing by Kristiaan Hoedemakers and Natacha Beau. 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The other members of the consortium are: Natural History Museum of Denmark, Copenhagen, Denmark; Naturalis Biodiversity Center, Leiden, the Netherlands; Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain; Leibniz Institute for the Analysis of Biodiversity Change, Bonn – Hamburg, Germany; National Museum of the Czech Republic, Prague, Czech Republic; The Steinhardt Museum of Natural History, Tel Aviv, Israël. KORN D. & GHADERI A., Late Permian nautiloids from Julfa (NW Iran) 113