A new furry lobster (Achelata, Synaxidae) and a forgotten crab (Brachyura, Homolidae) from the Early Cretaceous of France

2025  47  21 geodiversitas Geodiversitas est une revue en flux continu publiée par les Publications scientifiques du Muséum, Paris Geodiversitas is a fast track journal published by the Museum Science Press, Paris Les Publications scientifiques du Muséum publient aussi / The Museum Science Press also publish: Adansonia, Zoosystema, Anthropozoologica, European Journal of Taxonomy, Naturae, Cryptogamie sous-sections Algologie, Bryologie, Mycologie, Comptes Rendus Palevol Diffusion – Publications scientifiques Muséum national d’Histoire naturelle CP 41 – 57 rue Cuvier F-75231 Paris cedex 05 (France) Tél. : 33 (0)1 40 79 48 05 / Fax : 33 (0)1 40 79 38 40 [email protected] / http://sciencepress.mnhn.fr © Publications scientifiques du Muséum national d’Histoire naturelle, Paris, 2025 ISSN (imprimé / print) : 1280-9659/ ISSN (électronique / electronic) : 1638-9395 Directeur De la publication / Publication director : Gilles Bloch, Président du Muséum national d’Histoire naturelle réDacteur en chef / editor-in-chief : Didier Merle réDacteur associé / associate editor: Sylvain Charbonnier assistant De réDaction / assistant editor : Emmanuel Côtez ([email protected]) Mise en page / Page layout : Emmanuel Côtez coMité scientifique / scientific board : Christine Argot (Muséum national d’Histoire naturelle, Paris) Beatrix Azanza (Museo Nacional de Ciencias Naturales, Madrid) Raymond L. Bernor (Howard University, Washington DC) Henning Blom (Uppsala University) Gaël Clément (Muséum national d’Histoire naturelle, Paris) Ted Daeschler (Academy of Natural Sciences, Philadelphie) Cédric Del Rio (Muséum national d’Histoire naturelle) Gregory D. Edgecombe (The Natural History Museum, Londres) Ursula Göhlich (Natural History Museum Vienna) Jin Meng (American Museum of Natural History, New York) Brigitte Meyer-Berthaud (CIRAD, Montpellier) Zhu Min (Chinese Academy of Sciences, Pékin) Isabelle Rouget (Muséum national d’Histoire naturelle, Paris) Sevket Sen (Muséum national d’Histoire naturelle, Paris, retraité) Stanislav Štamberg (Museum of Eastern Bohemia, Hradec Králové) Paul Taylor (The Natural History Museum, Londres, retraité) couverture / cover : Réalisée à partir des Figures de l’article/Made from the Figures of the article. Geodiversitas est indexé dans / Geodiversitas is indexed in: – Science Citation Index Expanded (SciSearch®) – ISI Alerting Services® – Current Contents® / Physical, Chemical, and Earth Sciences® – Scopus® Geodiversitas est distribué en version électronique par / Geodiversitas is distributed electronically by: – BioOne® (http://www.bioone.org) Les articles ainsi que les nouveautés nomenclaturales publiés dans Geodiversitas sont référencés par / Articles and nomenclatural novelties published in Geodiversitas are referenced by: – ZooBank® (http://zoobank.org) 739 GEODIVERSITAS • 2025 • 47 (21) © Publications scientifiques du Muséum national d’Histoire naturelle, Paris. www.geodiversitas.com KEY WORDS Crustacea, Reptantia, Achelata, Brachyura, France, Early Cretaceous, Aptian, new genus, new species, new combination. urn:lsid:zoobank.org:pub:82DED0A8-B32C-4D4F-A378-20C8EEBE0AFD Charbonnier S., Garassino A. & Brochet R. 2025. — A new furry lobster (Achelata, Synaxidae) and a forgotten crab (Brachyura, Homolidae) from the Early Cretaceous of France. Geodiversitas 47 (21): 739-747. https://doi.org/10.5252/ geodiversitas2025v47a21. http://geodiversitas.com/47/21 ABSTRACT A new species of furry lobster (Decapoda, Achelata, Synaxidae) from the Early Cretaceous (Aptian) of Cheminon (Marne, France) is herein described. Cretapalibythus moniquae n. gen., n. sp. is erected based on two main morphological characters: the unarmed, rimmed, rostral margins and one elongate, prominent, unarmed anterolateral spine. It represents the first record of a furry lobster from the Early Cretaceous, filling the gap between the Late Jurassic (Oxfordian of France) and the Late Cretaceous (Cenomanian of Lebanon) synaxids. A species of brachyuran crab – Prosopon gignouxi Van Straelen, 1928 (Decapoda, Brachyura, Homolidae) – from the Early Cretaceous (Hauterivian) of Loriol-sur-Drôme (Drôme, France) is reappraised based on the rediscovery of its holotype. After its original report, this species was completely forgotten, and disappeared from the literature. It is herein placed in the genus Laeviprosopon Glaessner, 1933, recently reassigned to the Homoloidea De Haan, 1839, and a systematic discussion is elaborated with Laeviprosopon icaunensis (Van Straelen, 1936), the second species known from the Early Cretaceous (Hauterivian) of France. Sylvain CHARBONNIER Centre de recherche en paléontologie — Paris (CR2P UMR 7207), CNRS, MNHN, Sorbonne Université, Muséum national d’Histoire naturelle, case postale 38, 57 rue Cuvier, F-75231 Paris cedex 05 (France) [email protected] (corresponding author) Alessandro GARASSINO Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, 92350 CA (United States) [email protected] Richard BROCHET 3 Allée Élisa Deroche, 51000 Châlons-en-Champagne (France) [email protected] Submitted on 22 November 2024 | accepted on 15 December 2024 | published on 13 November 2025 A new furry lobster (Achelata, Synaxidae) and a forgotten crab (Brachyura, Homolidae) from the Early Cretaceous of France 740 GEODIVERSITAS • 2025 • 47 (21) Charbonnier S. et al. INTRODUCTION Early Cretaceous decapod crustaceans are relatively frequent in France and were studied since the middle of the nineteenth century with the pioneer work of Robineau-Desvoidy (1849). The exhaustive list of publications is long and out of the scope of the present study even if some milestone papers can be mentioned (Tribolet 1875, 1876; Van Straelen 1936; Devillez etal. 2016). We describe herein two different Early Cretaceous crustaceans: a synaxid lobster (Achelata: Synaxidae Spence Bate, 1881) and a brachyuran crab (Homoloidea: Homolidae De Haan, 1839) from the Paris Basin and the south-eastern France Basin respectively (Fig 1). Synaxid lobsters, commonly referred to as furry lobsters or coral lobsters are relatively rare in the modern marine communities (three extant species) but they seem to have been more diverse in the past with representatives from the Late Jurassic to the Late Eocene (six species: Bachmayer 1959; De Angeli& Garassino 2014; Fraaije etal. 2020; Garassino& Pasini 2020; Fraaije etal. 2023). The new specimen described herein as a new genus and new species was recently collected in the Aptian clays from Cheminon (Marne department, Grand Est region, France). It represents the first record of a furry lobster from the Early Cretaceous, filling the gap between the Late Jurassic (Oxfordian of France and Poland, Tithonian of Czech Republic) and the Late Cretaceous (Cenomanian of Lebanon) representatives. The new approach to the systematics of Laeviprosopon Glaessner, 1933 (Brachyura: Homolidae) and the discussion about the molting process of the early brachyurans proposed by Starzyk etal. (2023) was the starting point for the reappraisal of the forgotten species Prosopon gignouxi Van Straelen, 1928. It was originally described based on a single specimen collected by Maurice Gignoux (1881-1955), a renowned French geologist, specialist on the stratigraphy of the Alps (Jacob 1955; Moret 1956). The specimen was collected at Loriol-sur-Drôme (Drôme department, RhôneAlpes-Auvergne region) where Early Cretaceous (Hauterivian) marly limestones and marls alternations outcrop. We discuss herein the systematic placement of this forgotten species and its presence in bathyal sediments. MATERIAL AND GEOLOGICAL SETTING (Fig. 1) The holotype of the new furry lobster Cretapalibythus moniquae n. gen., n. sp. (MNHN.F.A95413, Brochet coll.) is housed in the palaeontological collection of the Muséum national d’Histoire naturelle, Paris, France. It corresponds to a threedimensionally preserved isolated carapace encrusted by pyrite mainly in the frontal region. One of the co-authors (RB), who is an amateur palaeontologist and specialist of decapod crustaceans, collected it in a lower Aptian clays from an open-pit mining at Cheminon (Marne department, Grand Est region, France). Supplementary stratigraphical data about the early Aptian deposits of Marne are available in Stchépinsky etal. (1959) and Vernhet (2007). The Cheminon quarry is located in the eastern margin of the Paris Basin, which was occupied during the Aptian by a narrow epicontinental sea (strait) between different landmasses and connecting the Tethys Ocean located to the south-east to the Boreal realm toward the north-west (Masse etal. 2000; see Deconinck etal. 2021: fig. 1). The holotype of Prosopon gignouxi Van Straelen, 1928 (UJFID1826, Gignoux coll.) is housed in the palaeontological collection at the Observatoire des Sciences de l’Univers de Grenoble, Université Grenoble Alpes, France. It corresponds to a threedimensionally preserved corpse imbedded in a small block of a grey-blue marl, and visible in dorsal view. Its nearly complete carapace (except front and posterior margin) is in conjunction with partially preserved pereiopods 2 to 4. It was collected during a field trip by Maurice Gignoux in the Hauterivian from Loriol-sur-Drôme (Drôme department, Rhône-Alpes-Auvergne region, France). Supplementary stratigraphical data about the Hauterivian deposits of Drôme are available in Chenevoy etal. (1977) and Gonzalez& Saint-Martin (2007). The Loriol-surDrôme outcrop is located in south-eastern France, which was MOTS CLÉS Crustacea, Reptantia, Achelata, Brachyura, France, Crétacé inférieur, Aptien, genre nouveau, espèce nouvelle, combinaison nouvelle. RÉSUMÉ Une nouvelle langouste à fourrure (Achelata, Synaxidae) et un crabe oublié (Brachyura, Homolidae) du Crétacé inférieur de France. Une nouvelle espèce de langouste à fourrure (Decapoda, Achelata, Synaxidae) du Crétacé inférieur (Aptien) de Cheminon (Marne, France) est ici décrite sous le nom Cretapalibythus moniquae n.gen., n.sp., à partir de deux caractères morphologiques principaux: des marges rostrales carénées et sans épines et une grande et longue épine antérolatérale non ornée. Elle représente la première mention d’une langouste à fourrure dans le Crétacé inférieur et comble le fossé entre les synaxidés du Jurassique supérieur (Oxfordien de France) et du Crétacé supérieur (Cénomanien du Liban). Une espèce de crabe brachyoure – Prosopon gignouxi Van Straelen, 1928 (Decapoda, Brachyura, Homolidae) – du Crétacé inférieur (Hauterivien) de Loriol-sur-Drôme (Drôme, France) est révisée à partir de la redécouverte de son holotype. Après sa publication originale, cette espèce a été complètement oubliée et a disparu de la littérature. Elle est ici placée dans le genre Laeviprosopon Glaessner, 1933, récemment assigné aux Homoloidea De Haan, 1839, et une discussion systématique est proposée avec Laeviprosopon icaunensis (Van Straelen, 1936), la seconde espèce connue dans le Crétacé inférieur (Hauterivien) de France. 741 A new furry lobster (Achelata, Synaxidae) and a forgotten crab (Brachyura, Homolidae) from the Early Cretaceous of France GEODIVERSITAS • 2025 • 47 (21) occupied during the Hauterivian by the Vocontian Trough, part of the south-eastern France Basin (Chenevoy etal. 1977; Ferry& Groshény 2013). The deep marine sedimentation was characterized by limestone-marl alternations affected by slumps, typical of the Vocontian Trough, which was limited by carbonate platforms (Ferry& Groshény 2013; see Ferry 2017: fig. 2). The holotype of Laeviprosopon icaunensis (Van Straelen, 1936), herein considered for comparison, is housed at the Muséum d’Histoire naturelle d’Auxerre, France (MHN-Aux-2012.0-8). It corresponds to a much-damaged carapace collected in the vicinity of Auxerre (Yonne department, Bourgogne-Franche Comté region, France), without indication of a more precise outcrop. Van Straelen (1936: 26) noted that the specific epithet alludes to the Yonne river – Icauna in Latin – inside the valley where the outcrop where the specimen was collected is located. The specimen was originally attributed to the Neocomian by Van Straelen (1936), and its age was later precised as Hauterivian by Houdard (1938). The Auxerre area is located in the south-eastern margin of the Paris Basin, which was characterized during the Hauterivian by the shallow marine sediments of the Calcaires à Spatangues Formation (Rat etal. 1987; Walter 1996). After Benetti etal. (2013), this formation is a window on the little-known benthic communities that thrived in shallow marine environments in the Early Cretaceous of France. We add that the fossil richness of this formation has attracted the attention of palaeontologists since the middle of the nineteenth century (see synthesis by Corroy 1925). Other Cretaceous crustaceans from the Auxerre region were described mainly by Van Straelen (1928, 1936), and before him by A. Milne-Edwards (1865) and RobineauDesvoidy (1849). AbbreviAtions Institutional abbreviations MNHN Muséum national d’Histoire naturelle, Paris; F MNHN, collection de Paléontologie; MHN-Aux Muséum d’Histoire naturelle d’Auxerre, France; UJF-ID Observatoire des Sciences de l’Univers de Grenoble, Université Grenoble Alpes, France. Anatomical abbreviation P1-P5 pereiopods 1 to 5. SYSTEMATIC PALAEONTOLOGY Order DECAPODA Latreille, 1802 Infraorder ACHELATA Scholtz& Richter, 1995 Family synAxidAe Spence Bate, 1881 Genus Cretapalibythus n. gen. urn:lsid:zoobank.org:act:D4D64321-6E85-487A-8AC3-B4C72AE870E8 etymology. — The generic name is a combination of the Cretaceous period and the extant synaxid Palibythus Davie, 1990, that shows many morphological affinities with the new genus. The gender of the genus is masculine. type species. — Cretapalibythus moniquae n. sp. diAgnosis. — Elongate, subrectangular carapace as wide as anteriorly and posteriorly; broad rostrum, wider than long, with pointed extremity; rostral lateral margins marked by a rimmed, unarmed carinae ending in a subacute spine; tuberculate post-rostral carinae; large concave post-orbital margin; one elongate, prominent, unarmed anterolateral spine; deep cervical groove; dorsal carapace covered with small pits uniformly arranged. Cretapalibythus moniquae n. gen., n. sp. (Fig. 2) urn:lsid:zoobank.org:act:214C9F26-B7AC-44BC-B85B-FCBC86708965 diAgnosis. — As for genus. etymology. — The specific epithet honors Monique Brochet, mother of one of the authors. t ype mAteriAl . — Holotype. France • 1 specimen (carapace; adult); Grand-Est, Marne, Cheminon; Early Cretaceous, early Aptian; Richard Brochet leg.; MNHN.F.A95413. type locAlity. — Cheminon, Marne, Grand-Est, France. type Age. — Early Cretaceous (early Aptian). description Carapace Elongate, subrectangular carapace not narrowing anteriorly (total length:17mm; total width: 9mm); broad rostrum, wider than long, slightly concave side to side, with pointed extremity; rostral lateral margins marked by a rimmed tuberParis Basin Aquitaine Basin South-East Basin Massif Central Armorican Massif Jura Burgundy Vosges Seuil du Poitou 200 km N Paris Loriol-surDrôme Auxerre Cheminon fig. 1. — Map of France with the three main sedimentary basins and the locations of studied specimens. 742 GEODIVERSITAS • 2025 • 47 (21) Charbonnier S. et al. culate carina ending in a subacute spine; two well-marked tuberculate submedian, post-rostral carinae directed backward as extension of rostral lateral margins, reaching slightly less than half way towards cervical groove; wide orbits with tuberculate orbital margins; large, concave post-orbital margin; one elongate, prominent, unarmed anterolateral spine; carapace weakly constricted at level of cervical groove behind anterolateral spine; straight, unarmed posterolateral margins; deep cervical groove; wide, rounded urogastric region; subtriangular cardiac region narrowing anteriorly; poorly preserved posterior margin as width as frontal margin; dorsal carapace covered with small pits uniformly arranged (as preserved). discussion According to several authors (Holthuis 1991; Martin& Davis 2001; Lavalli& Spanier 2010; Schweitzer etal. 2015), the Achelata are subdivided into four families: Cancrinidae Beurlen, 1930, Palinuridae Latreille, 1802, Scyllaridae Latreille, 1825, and Synaxidae. Extant synaxid lobsters, including only two genera (Palibythus Davie, 1990 and Palinurellus von Martens, 1878), are easily differentiated from palinurid lobsters in that they lack frontal supra-orbital horns. However, according to Fraaije etal. (2023), synaxids bear a prominent, broad-based rostrum, a tapered carapace, not depressed or flattened, but tubular, and the anterior part of carapace (rostrum to cervical groove) exceeds A E AB r als sprc ur e1e cd pm py sprc als rlmrlm o sprc e1e rlm o r als cd ur pm als C D als r sprc rlm o alsr sprc rlm als o o fig. 2 . — Holotype MNHN.F.A95413 (Brochet coll.) of Cretapalibythus moniquae n. gen., n. sp. (Achelata, Synaxidae) from the Aptian of Cheminon, Marne, France: A, carapace in dorsal view; B, interpretative line drawing; C, close-up of left cephalic region; D, frontal view of carapace; E, left lateral view of carapace. Abbreviations: als, anterolateral spine; cd, cardiac region; e1e, cervical groove; o, orbit; pm, posterior margin; py, pyrite encrustation; r, rostrum; rlm, rostral lateral margin; sprc, submedian post-rostral carina; ur, urogastric region. Scale bars: 5 mm. Photographs: Richard Brochet. 743 A new furry lobster (Achelata, Synaxidae) and a forgotten crab (Brachyura, Homolidae) from the Early Cretaceous of France GEODIVERSITAS • 2025 • 47 (21) the posterior one (cervical groove to posterior margin) in length. Moreover, synaxid lobsters differ from scyllarid lobsters in having a long and broad triangular rostrum and a tapered anterior carapace that is not depressed. Finally, synaxid lobsters differ from cancrinid lobsters in having short antennal flagella. According to Holthuis (1991: 90) the members of Synaxidae have carapaces lacking frontal horns, but with a large, broad, and flat rostrum, and the dorsal surface covered only with granules or tubercles. Cretapalibythus n. gen. fits the main characters of this family to which it is assigned. The representatives of the Synaxidae are rare components of extant benthic communities, as reported by Holthuis (1991). The fossil record of the family is instead more common, especially from reefal settings of Late Jurassic age in Europe with Palaeopalinurellus culocervus Fraaije, Van Bakel, Jagt& Brochet, 2020 (Oxfordian, France), Palaeopalinurellus strambergensis Bachmayer, 1959 (Tithonian, Czech Republic), and Palaeosynaxes montserratae Fraaije, van Bakel, Jagt, Krobicki, Ossó, Palero& Wallaard, 2023 (Oxfordian, Poland). Palaeopalinurellus jbeilensis Garassino& Pasini, 2020 (Cenomanian, Lebanon) is the first record of Palaeopalinurellus out of Europe and the sole species from the Late Cretaceous. Finally, Palinurellus bericus De Angeli& Garassino, 2014 (Priabonian, Italy) is the so far oldest fossil species of the extant genus Palinurellus. Cretapalibythus n. gen. differs from Palaeopalinurellus and Palaeosynaxes in having the dorsal carapace covered with small pits uniformly arranged (vs anterior part with irregularly tuberculate, posterior part densely covered with scale-like tubercles in Palaeopalinurellus and carapace densely covered with coarse, blunt, forwardly directed tubercles in Palaeosynaxes). It differs from Palinurellus in having a rostrum wider than long and tuberculate post-rostral carinae (vs rostrum longer than wide without post-rostral carinae in Palinurellus). Based on Davie (1990), Cretapalibythus n. gen. shares with the extant Palibythus the rostrum wider than long and the tuberculate post-rostral carinae. However, besides its smaller size, the studied specimen differs from Palibythus in having unarmed, rimmed, rostral lateral margins (vs rostral lateral margin with several spines in Palibythus) and just one elongate, prominent, unarmed anterolateral spine (vs anterolateral spines with several spines in Palibythus). Based on these observations, Cretapalibythus n. gen. represents the first report of a furry lobster from the Early Cretaceous, filling the gap between the Late Jurassic and Late Cretaceous synaxid lobsters. Finally, it represents the second report of a fossil synaxid lobster from France after the report of the Late Jurassic (Oxfordian) Palaeopalinurellus culocervus by Fraaije etal. (2020). Infraorder BRACHYURA Linnaeus, 1758 Superfamily HomoloideA De Haan, 1839 Family HomolidAe De Haan, 1839 Genus Laeviprosopon Glaessner, 1933 type species. — Prosopon laeve Meyer, 1857, by original designation. included species. — See Starzyk etal. (2023). Laeviprosopon gignouxi (Van Straelen, 1928), n.comb. (Fig. 3) Prosopon gignouxi Van Straelen, 1928: 606, figs1, 2; 1936: 26.— Withers 1951: 184. type mAteriAl. — Holotype. France • 1 specimen (carapace; adult); Auvergne-Rhône-Alpes, Drôme, Loriol-sur-Drôme; Early Cretaceous, Hauterivian; Maurice Gignoux leg.; UJF-ID1826. type locAlity. — Loriol-sur-Drôme, Drôme, Auvergne-RhôneAlpes, France. type Age. — Early Cretaceous, Hauterivian. originAl diAgnosis by Van Straelen (1928: 607). — Carapace convex transversally, inflected anteriorly, wider posteriorly, widest at level of posterior margin; half-circle-shaped cervical groove; gastro-antennal grove marking a median gastric region bearing two crests posteriorly at level of cervical groove; postcervical groove deep medially, originating a groove marking the mesobranchial region; branchiocardiac groove extending posteriorly, originating a forward-directed short groove marking the epibranchial region; hepatic regions with a groove; marked cardiac regions narrowing posteriorly bearing two tubercles posteriorly; grooved branchial regions on their anterior median part (literal translation from the original French text). systemAtic remArks According to Van Bakel etal. (2021: 7), Laeviprosopon has generally been included in the Prosopidae Meyer, 1860 by several authors (see Schweitzer& Feldmann 2008; Guinot 2019; Klompmaker etal. 2020; Starzyk 2020). However, Van Bakel etal. (2021) excluded it from this family, because it possesses a linea homolica (see Patrulius 1966; Collins& Wierzbowski 1985), a weakly projecting trifurcate front, a non-sinuous, arched concave posterior margin, and undefined orbits (the cornea resting on the dorsal carapace surface). In addition, Laeviprosopon usually has a complete oblique groove that subdivides the hepatic regions. The genus is interpreted as an early representative of the superfamily Homoloidea, and thus excluded from the Homolodromioidea Alcock, 1900, adopting the views expressed by several previous authors (Patrulius 1966; Collins& Wierzbowski 1985), and recently by Starzyk etal. (2023). However, the presence or not of a molting line similar to the linea homolica in Laeviprosopon is not well clarified yet though three species of the genus show this character. In the extant representatives of the Homolidae, the linea homolica is always present in all individuals, not in the molting specimens only (A.G., pers. obs. 2023). Anyway, the discussion of the systematics of Laeviprosopon is not the aim of the present note. In conclusion, we follow herein the most recent updated systematics proposed by Starzyk etal. (2023) for Laeviprosopon based on the presence of a molting line in the type species and other species of the genus. emended description Carapace Small carapace uniformly granulated, longer than wide moderately vaulted transversally and longitudinally; nearly straight frontal margin poorly preserved; rostrum not preserved; poorly 744 GEODIVERSITAS • 2025 • 47 (21) Charbonnier S. et al. preserved ?small orbits; anterolateral margins slightly narrowing frontally; posterolateral margins slightly rounded weakly narrowing posteriorly: posterior margin not preserved; very narrow epigastric region; slightly swollen hepatic regions; slightly swollen protogastric regions; elongate, narrow anterior metagastric process; mesogastric region with a pair of swollen distal tubercles and a pair of small mesogastric groove tubercles; small gastric pits between mesoand urogastric regions; narrow urogastric region; diamond-shaped cardiac region with a pair of aligned tubercles medially and one tubercle distally; wide intestinal region; slightly swollen epi-, meta-, and mesobranchial regions; deep cervical groove reaching lateral margins; deep branchiocardiac grooves, delimiting cardiac region and reaching posterior margin; lateral transverse groove joining cervical to branchiocardiac grooves; molting line not present. Thoracic appendages Elongate, subcylindrical P2-P4 partially preserved, flattened laterally, ovoidal in transverse section; elongate P2-P4meri with smooth dorsal and ventral margins; narrow subtriangular P2-P4 carpi shorter than meri. discussion Van Straelen (1928: 606) assigned the studied specimen to “the tribe Dromiacea, subtribe Dromiidea and the family Prosoponidae”, but he did not provide a detailed discussion to justify his assignment, limiting to comparisons with several other Jurassic and Cretaceous dromiacean crabs known at that time. Prosopon gignouxi was not reported or discussed in any systematic study after Withers (1951). Our examination of the holotype leads us to highlight major affinities with Laeviprosopon, which was recently revised by Starzyk etal. (2023). According to these authors, the diagnostic characters of Laeviprosopon are as follows: carapace rectangular, longer than wide, often narrowing slightly anteriorly; regions well defined by deep grooves; rostrum, projected well beyond orbits; orbits shallow, rimmed, directed forward, located at base of rostrum; augenrest poorly formed to nearly absent; subhepatic region inflated, sometimes greatly; epigastric, protogastric, and hepatic regions separated by transverse grooves into three anteriorly to posteriorly successive regions; cervical groove deep, strongly concave forward to sinuous; branchiocardiac groove shallower than cervical groove; postcervical groove short, interrupted axially; posterolateral portions of carapace often broken as if less calcified than other portions of carapace. Although the holotype does not preserve a complete frontal margin, rostrum, and orbits, and despite the lack of a molting line (linea homolica), the morphological characters listed in our updated description are diagnostic of Laeviprosopon, and we therefore propose the new combination Laeviprosopon gignouxi (Van Straelen, 1928), n. comb. A B C pgms mgt gp epbr cd mgr P2 P3 P4 P4 ur mtb msb ptg mtb ptg epbr fig. 3. — Holotype UJF-ID1826 (Gignoux coll.) of Laeviprosopon gignouxi (Van Straelen, 1928), n. comb. (Brachyura, Homolidae) from the Hauterivian of Loriolsur-Drôme, Drôme, France: dorsal view of carapace whitened with ammonium chloride (A), under natural light (B), and interpretative line drawing (C). Abbreviations: cd, cardiac region; epbr, epibranchial region; gp, gastric pit; mgr, mesogastric region; mgt, mesogastric groove tubercle; msb, mesobranchial region; mtb, metabranchial region; pgms, posterior gastric muscle scars; ptg, protogastric region; P2-P4, second to fourth pereiopods; ur, urogastric region. Scale bars: 5 mm. Photographs: Lilian Cazes. 745 A new furry lobster (Achelata, Synaxidae) and a forgotten crab (Brachyura, Homolidae) from the Early Cretaceous of France GEODIVERSITAS • 2025 • 47 (21) We add that the holotype is a corpse and is furthermore the only specimen partially preserving P2-P4, previously unknown in all representatives of the family. According to Starzyk etal. (2023), Laeviprosopon icaunensis (Van Straelen, 1936) from the Hauterivian of Yonne (Bourgogne-Franche-Comté) is the only other species of the genus reported to date in France (Fig. 4). Although most of the central dorsal carapace is not preserved in the holotype of L.icaunensis, it differs from L.gignouxi n.comb. by a carapace bearing hepatic regions with two grooves, a cervical groove not rimmed, and the median part of branchial regions without groove. Moreover, L.icaunensis has a smooth carapace (vs granulated in L.gignouxi n.comb.), and is more convex antero-posteriorly with a strongly downward proE AB CD F ptg epbr ptg hr epbr mtb msb r epg fig. 4. — Holotype MHN-Aux-2012.0-8 of Laeviprosopon icaunensis (Van Straelen, 1936) (Brachyura, Homolidae) from the Hauterivian of Auxerre, Yonne, France: carapace in dorsal (A-B), left lateral (C-D) and frontal (E-F) views; natural light and whitened with ammonium chloride. Abbreviations: epg, epigastric region; epbr, epibranchial region; hr, hepatic region; ptg, protogastric region; msb, mesobranchial region; mtb, metabranchial; r, rostrum. Scale bars: 5 mm. Photographs: Lilian Cazes.