Notes on the taxonomy of Frevillea A. Milne-Edwards, 1880 (Crustacea, Brachyura, Goneplacoidea), with the description of a new genus for F. sigsbei A. Milne-Edwards, 1880

Directeur De la publication / Publication director : Gilles Bloch Président du Muséum national d’Histoire naturelle réDactrice en chef / editor-in-chief : Laure Desutter-Grandcolas assistante De réDaction / assistant editor : Anne Mabille ([email protected]) Mise en page / Page layout : Anne Mabille coMité scientifique / scientific board : Nesrine Akkari (Naturhistorisches Museum, Vienne, Autriche) Maria Marta Cigliano (Museo de La Plata, La Plata, Argentine) Serge Gofas (Universidad de Málaga, Málaga, Espagne) Sylvain Hugel (CNRS, Université de Strasbourg, France) Marco Isaia (Università degli Studi di Torino, Turin, Italie) Rafael Marquez (CSIC, Madrid, Espagne) Jose Christopher E. Mendoza (Lee Kong Chian Natural History Museum, Singapour) Annemarie Ohler (MNHN, Paris, France) Jean-Yves Rasplus (INRA, Montferrier-sur-Lez, France) Wanda M. Weiner (Polish Academy of Sciences, Cracovie, Pologne) couverture / cover : Diuplax sigsbei (A. Milne-Edwards, 1880) after A. Milne-Edwards & Bouvier (1923: pl. 6, fig. 2). 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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] / https://sciencepress.mnhn.fr © Publications scientifiques du Muséum national d’Histoire naturelle, Paris, 2024 ISSN (imprimé / print) : 1280-9551/ ISSN (électronique / electronic) : 1638-9387 733 ZOOSYSTEMA • 2024 • 46 (29) © Publications scientifiques du Muséum national d’Histoire naturelle, Paris. www.zoosystema.com urn:lsid:zoobank.org:pub:B8FB5A89-4811-4DB1-819B-442067652F3E Ng P. K. L., Castro P. & Rodríguez Moreno P. A. 2024. — Notes on the taxonomy of Frevillea A. Milne-Edwards, 1880 (Crustacea, Brachyura, Goneplacoidea), with the description of a new genus for F. sigsbei A. Milne-Edwards, 1880. Zoosystema 46 (29): 733-748. https://doi.org/10.5252/zoosystema2024v46a29. http://zoosystema.com/46/29 ABSTRACT The identities of the Western Atlantic brachyuran crabs Frevillea barbata A. Milne-Edwards, 1880, F.rosaea A. Milne-Edwards, 1880, F.tridentata A. Milne-Edwards, 1880, and F.sigsbei A. MilneEdwards, 1880, originally placed in Goneplacidae MacLeay, 1838, are clarified on the basis of the examination of type material as well as of additional specimens. The correct identity of the type material of the four species is resolved. A new genus, Diuplax n.gen., is described for F.sigsbei, which had previously been transferred to Goneplax Leach, 1814 (family Goneplacidae). The new genus is distinguished from Goneplax s.str. by having a short cheliped merus that possesses a low submedian tubercle on its dorsal margin (elongated merus with a distinct short submedian spine on its dorsal margin in Goneplax s.str.) and the unarmed dorsal margin of the meri of the ambulatory legs (with distinct subdistal spine in Goneplax s.str.). Frevillea barbata and F.rosaea are now in the Euryplacidae Stimpson, 1871, F.sigsbei is in Diuplax n.gen. (Goneplacidae, Goneplacoidea MacLeay, 1838), whereas F.tridentata is in Trapezioplax Guinot, 1969 in Pseudorhombilidae Alcock, 1900 (Xanthoidea MacLeay, 1838). Peter K. L. NG Lee Kong Chian Natural History Museum, Conservatory Drive, National University of Singapore, Singapore 117377 (Republic of Singapore) Peter CASTRO Biological Sciences Department, California State Polytechnic University, Pomona, CA 91768 (United States) Paula A. RODRÍGUEZ MORENO Direction générale déléguée aux collections, case postale 53, 57 rue Cuvier, F-75231 Paris cedex 05 (France) [email protected] (corresponding author) Submitted on 15 December 2023 | Accepted on 15 April 2024 | Published on 12 November 2024 Notes on the taxonomy of Frevillea A. Milne-Edwards, 1880 (Crustacea, Brachyura, Goneplacoidea), with the description of a new genus for F. sigsbei A. Milne-Edwards, 1880 KEY WORDS Western Atlantic region, Goneplacoidea, nomenclature, new combination, new genus. 734 ZOOSYSTEMA • 2024 • 46 (29) Ng P. K. L. et al. RÉSUMÉ Notes sur la taxonomie de Frevillea A. Milne-Edwards, 1880 (Crustacea, Brachyura, Goneplacoidea), avec la description d’un nouveau genre pour F. sigsbei A. Milne-Edwards, 1880. L’identité des crabes de la région atlantique occidentale Frevillea barbata A. Milne-Edwards, 1880, F.rosaea A. Milne-Edwards, 1880, F.tridentata A. Milne-Edwards, 1880, et de F.sigsbei A. MilneEdwards, 1880, originalement placés dans les Goneplacidae MacLeay, 1838, est clarifiée sur la base de l’examen des spécimens types ainsi que de spécimens additionnels. L’identité correcte du matériel type des quatre espèces est résolue. Un nouveau genre, Diuplax n.gen., est décrit pour F.sigsbei, antérieurement transféré dans Goneplax Leach, 1814 (Goneplacidae). Le nouveau genre se distingue de Goneplax s.str. par le court mérus du chélipède doté d’un faible tubercule submédian sur le bord dorsal (mérus nettement plus allongé, avec une courte épine sur le bord dorsal chez Goneplax s.str.) et le bord dorsal du mérus des pattes ambulatoires sans épine (une épine subdistale chez Goneplax s.str.). Frevillea barbata et F. rosaea font maintenant partie des Euryplacidae Stimpson, 1871 et F.sigsbei est dans Diuplax n. gen. (Goneplacidae, Goneplacoidea MacLeay, 1838), tandis que F.tridentata est dans Trapezioplax Guinot, 1969 dans les Pseudorhombilidae Alcock, 1900 (Xanthoidea MacLeay, 1838). INTRODUCTION As part of his report on the Brachyura collected in the Gulf of Mexico, Caribbean Sea, and the Atlantic coast of the United States by the United States Coast Survey and Geological Service (USCSGS) Steamer George S.Blake between 1877 and 1879, Alphonse Milne-Edwards (1880) established the genus Frevillea for four species of catometopous crabs: F.barbata A.Milne-Edwards, 1880, F.rosaea A. Milne-Edwards, 1880, F.sigsbei A. Milne-Edwards, 1880, and F.tridentata A. MilneEdwards, 1880. Much later, A. Milne-Edwards& Bouvier (1923) treated the genus and species in more detail, adding notes on the material they had available as well as providing for the first time, figures of the four species. No type species was originally designated for Frevillea, but Rathbun (1918: 25) selected F.barbata as the type species. Guinot (1969a-c, 1971) discussed the taxonomy of various goneplacids at length and restricted Frevillea to F.barbata and F. rosaea, transferring, with doubt, F.sigsbei to Goneplax Leach, 1814, and referred F.tridentata to a new genus, Trapezioplax Guinot, 1969 (cf. Guinot 1969c). In his revision of the Goneplacidae MacLeay, 1838 s.str., Castro (2007) recognised F.sigsbei as a valid species of Goneplax (see also Ng etal. 2008); Trapezioplax is now in Pseudorhombilidae Alcock, 1900 (see Guinot 1971; Ng etal. 2008; Thoma etal. 2014), and Frevillea s.str. is in Euryplacidae Stimpson, 1871 (Guinot 1971; Ng etal. 2008; Castro& Ng 2010). As part of collection management in the Muséum national d’Histoire naturelle, Paris (MNHN), a technician, Laura Flamme, recently highlighted to the second author that the type specimens of F.barbata and F. rosaea as recorded were probably mislabelled and/or mixed. Taking advantage of a visit to the MNHN in 2023, the first author checked the MNHN’s holdings of Frevillea with the third author at the request of the second author, who had examined and made notes of this material in 2006 as part of his studies on Goneplacoidea (see Castro 2007; Castro& Ng 2010). The first author also sought assistance from staff in the Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States (MCZ), where a part of A. Milne-Edwards’ (1880) original material is housed. One of the results of our investigation was the establishment of a new genus, Diuplax n.gen., for Frevillea sigsbei A. Milne-Edwards, 1880. MATERIAL AND METHODS MeasureMents Measurements (in millimetres) are of the maximum carapace length followed by width (including teeth), respectively. The original type material examined was re-measured using the same method used for the more recent material. The terminology used follows Davie etal. (2015). Specimens examined are deposited in MCZ, ZRC and MNHN. abbreviations Institutions MCZ Museum of Comparative Zoology, Harvard University, Cambridge, MA; MNHN Muséum national d’Histoire naturelle, Paris; ZRC Zoological Reference Collection, Lee Kong Chian Natural History Museum, National University of Singapore. Morphology G1 male first gonopod; G2 male second gonopod. noMenclature The specimens of A. Milne-Edwards (1880) and A. MilneEdwards& Bouvier (1923) have been variously listed, labelled, and/or databased as “type”, “cotypes”, “holotype”, “lectotype” or “paralectotype” by various authors and curators. This confusion stems from the manner these authors identified which is the “type” (in the sense of the name-bearing specimen) and how they listed their material. They also did not state where each specimen was deposited (i.e., MCZ or MNHN). Specimens were probably only shared between the two museums MOTS CLÉS Région atlantique occidentale, Goneplacoidea, nomenclature, combinaison nouvelle, genre nouveau. 735 Taxonomy of Frevillea and description of Diuplax n. gen. ZOOSYSTEMA • 2024 • 46 (29) later on. The situation was compounded by Rathbun’s (1918) nomenclatural actions (see below). The present decisions on which specimens belongs to the syntype series and whether they are holotypes or lectotypes follow a strict interpretation of the current zoological code (ICZN 1999). Alphonse Milne-Edwards (1880) provided collection data, measurements and sex for only one specimen for each of the four species he described (F.barbata, F.rosaea, F.sigsbei, and F.tridentata). We nevertheless cannot assume that the four specimens in question are the holotypes of the four species, because he never stated anywhere in the text which were the type specimens. Furthermore, he did not say if these four specimens were the ones he had. It is worth noting, however, that when A. Milne-Edwards (1880: 15-16) gave the measurements of the specimen for each of the four species of Frevillea, he writes “Largeur de la carapace d’un mâle” [Carapace length of one male] (for F.barbata), “Largeur de la carapace d’un [sic] femelle” [Carapace length of one female] (for F. rosaea), “Largeur de la carapace d’une femelle” [Carapace length of one female] (for F. tridentata), and “Largeur de la carapace d’une femelle chargée d’œufs” [Carapace length of one female with eggs] (for F.sigsbei). The wording he used suggests that he had more than one specimen of each species. Article 73.1.2 of the Code also states that for a specimen to be a holotype it should be stated as such or in an equivalent manner in the original publication. Recommendation 73F of the code advises that “Where no holotype or syntype was fixed for a nominal species-group taxon established before 2000, and when it is possible that the nominal species-group taxon was based on more than one specimen, an author should proceed as though syntypes may exist and, where appropriate, should designate a lectotype rather than assume a holotype.” Rathbun (1918) subsequently “mentioned” the type material of the four species as follows: F.barbata, “type in Paris Mus.” and “male holotype (Paris Mus.)” (Rathbun 1918: 26); F.rosaea, “holotype in Paris Mus.” (Rathbun 1918: 27); F.tridentata, “holotype in Paris Mus.” (Rathbun 1918: 29); and F.sigsbei, “holotype in Paris Mus.” (Rathbun 1918: 26). She apparently did not examine these “holotypes” as she listed them under her “other records” or “type locality” and not as “material examined”, and all the information (location and sex) for these was exactly as stated in A. Milne-Edwards (1880). While she did not indicate how many specimens there were, her action nevertheless constitutes a valid lectotype designation under Articles 74.5 and 74.6, even if the repository, as we now know, is incorrect. It is not known why she assumed the “holotypes” were in MNHN and not in MCZ. Rathbun had visited MNHN at the beginning of the 20th century to mainly work on freshwater crabs in Paris (see Bouvier, in Rathbun 1904: 225-226) but she apparently did not examine Frevillea during that time. While we cannot be certain as there are no records for this, it is possible that when Rathbun (1918) published her work, all the syntypes of the four species were still at Paris, and some of them were only sent back to MCZ during or after 1918, or more likely, after the paper of A. Milne-Edwards& Bouvier (1923). This would explain why Rathbun (1918) did not mention the MCZ type material for the four species. The later publication by A. Milne-Edwards& Bouvier (1923) showed that there were more specimens of each of the four species of Frevillea, and identified the specimen mentioned by A. Milne-Edwards (1880) to be the “type” (in the sense of the name-bearing specimen) for each taxon. The designated “type” for each species is the same as those selected by Rathbun (1918). As far as the type status of the additional specimens listed by A. Milne-Edwards& Bouvier (1923), the best solution is to strictly follow Articles 72.4.1 and 72.4.1.1 of the ICZN code, which state “The type series of a nominal species-group taxon consists of all the specimens included by the author in the new nominal taxon (whether directly or by bibliographic reference), except any that the author expressly excludes from the type series [Art. 72.4.6], or refers to as distinct variants (e.g., by name, letter or number), or doubtfully attributes to the taxon.” and “For a nominal species or subspecies established before 2000, any evidence, published or unpublished, may be taken into account to determine what specimens constitute the type series”. It is clear then that A. Milne-Edwards (1880) had more than one specimen when he made the description even though he did not mention the others, and therefore must have used them when making his decision. In all cases, these additional specimens were from the same Blake station as the “type.” In addition, while A. Milne-Edwards& Bouvier (1923) did not identify the additional specimens as “cotypes” or the equivalent, they also do not explicitly exclude them as syntypes. As such, it is best to treat all the material of the species in A. Milne-Edwards& Bouvier (1923) as syntypes. With the identification of a name-bearing specimen or lectotype for each species by Rathbun (1918) and A. Milne-Edwards& Bouvier (1923), the remaining specimens are de facto paralectotypes. SYSTEMATICS Superfamily Goneplacoidea MacLeay, 1838 Family euryplacidae Stimpson, 1871 Genus Frevillea A. Milne-Edwards, 1880 Frevillea A. Milne-Edwards, 1880: 15. t ype species . — Frevillea barbata A. Milne-Edwards, 1880 (by designation, Rathbun 1918: 25; gender feminine). Frevillea barbata A. Milne-Edwards, 1880 (Figs1; 2) Frevillea barbata A. Milne-Edwards, 1880: 15.— Rathbun 1898: 287.— A. Milne-Edwards& Bouvier 1923: 336, fig.2, pl.2, figs10, 11, pl.7, figs1, 2.— Guinot 1969b: 513, pl.2, fig.2; 1971: 1080 [in list]; 1984: pl.1, fig.H.— Powers 1977: 114.— Soto 1985: 484, 487, 488; 1986: 3, 4, 36; 1991: 627.— Abele& Kim 1986: 54, 593, fig.a.— Boschi 2000: 82.— McLaughlin etal. 2005: 257 [in list].— Ng etal. 2008: 78 [in list].— Felder etal. 2009: 1081 [in list].— Thoma etal. 2009: 553, 563, figs1, 2.— Castro& Ng 2010: 53 (part). 736 ZOOSYSTEMA • 2024 • 46 (29) Ng P. K. L. et al. Goneplax barbata – Rathbun 1918: 25, 26, pl.4, figs1, 3, pl.5. Frevillea rosaea – Castro& Ng 2010: 56 (part) (not F.rosaea A.Milne-Edwards, 1880). Not Frevillea barbata – Poupin 1994: 48, pl.5e (= F.hirsuta (Borradaile, 1916)). H istory .— Frevillea barbata was described from Blake’s station36 in the Gulf of Mexico (23°13’N, 89°16’W) from a depth of 84fathoms (= 154m) (A. Milne-Edwards 1880: 15). Measurements were provided for one male (26.0 × 17.0mm), but no type was indicated (see above). For the species, Rathbun (1918: 26) stated: “type-locality, lat. 23° 13’ N.; long. 89° 16’ W., 84 fathoms, A B C DE FG H fig. 1 . — Frevillea barbata A. Milne-Edwards, 1880: A-D, lectotype ♂ (29.5 × 18.4 mm) (MCZ-IZ-CRU-9155); E, paralectotype ♀ (27.3 × 17.2 mm) (MCZ-IZCRU-9155); F, paralectotype ♂ (16.5 × 10.0 mm) (MNHN-IU-2014-7505); G, paralectotype ♀ (22.7 × 15.7 mm) (MNHN-IU-2014-7506); H, juvenile paralectotype ♀ (7.9 × 5.0 mm) (MNHN-IU-2014-7506): A, D-H, overall dorsal views; B, right chela; C, pleon. Credits: A-C after A. Milne-Edwards & Bouvier (1923: fig. 2; pl. 7, figs 1, 2); D, E, photographs by Alana Rivera, MCZ; , F-H, photographs by P. K. L. Ng. 737 Taxonomy of Frevillea and description of Diuplax n. gen. ZOOSYSTEMA • 2024 • 46 (29) station 36, Blake; type in Paris Mus.” and “Yucatan Channel; lat. 23° 13’ 00”N, long. 89° 16’ 00” W.; 84 fathoms; temp. 60° F.; station 36, U. S. C. S. Str, Blake; male holotype (Paris Mus.).”; and although she did not examine the specimen, her action constitutes the first valid designation of a lectotype for the species. Rathbun (1918: 26), however, did examine another Blake specimen in MCZ: “Off Grenada; lat. 12° 01’ 45” N.; long. 61°47’ 25” W.; 92 fathoms; fne. S.; Mar. 1, 1879; station 262, Blake; 1male (Cat. No. 4116. M. C. Z.).” Alphonse Milne-Edwards& Bouvier (1923: 336) elaborated that they studied one “type” male, one immature male, two adult females, and two juveniles. This ratified the name-bearing designation made by Rathbun (1918). Alphonse Milne-Edwards& Bouvier (1923) did not state the size of the type male (only one adult male is mentioned), but we AB C D E F fig. 2 . — Frevillea barbata A. Milne-Edwards, 1880: A, B, F, paralectotype ♂ (16.5 × 10.0 mm) (MNHN-IU-2014-7505); C, paralectotype ♀ (27.3 × 17.2 mm) (MCZ-IZ-CRU-9155); D, lectotype ♂ (29.5 × 18.4 mm) (MCZ-IZ-CRU-9155); E, paralectotype ♀ (22.7 × 15.7 mm) (MNHN-IU-2014-7506): A, left side of carapace and left cheliped; B, right chela; C-E, ventral view of cephalothorax and pleon; F, ♂ sternopleonal cavity. Credits: A, B, E, F photographs by P. K. L. Ng; C, D, photographs by Alana Rivera, MCZ. 738 ZOOSYSTEMA • 2024 • 46 (29) Ng P. K. L. et al. presume it is the one A. Milne-Edwards originally measured, i.e., 26.0 × 17.0mm. They figured the male pleon for the type male (A. Milne-Edwards& Bouvier 1923: fig.2), as well as the carapace and cheliped (pl.7, figs1, 2) and the fourth ambulatory leg (pl.2, figs10, 11) (Fig.1A-C). In any case, apparently Rathbun (1918) and A. Milne-Edwards& Bouvier (1923) selected the same specimen as the lectotype. Alphonse Milne-Edwards& Bouvier (1923: 337) also comment that “En dehors de la localité précédente qui se trouve dans le Golfe du Mexique au N.du Canal du Yucatan, l’espèce a été signalée, avec doute, au large de La Havane par Mlle Rathbun.” [Apart from the previous locality, which is in the Gulf of Mexico, N. of the Yucatan Channel, the species has been reported, with doubt, off Havana by Miss Rathbun.] (see Rathbun 1898). Guinot (1969b: 512, pl.12 fig.2) next recorded and figured a “cotype” female measuring 16.5 × 10.0mm from station 36. Castro& Ng (2010: 53) listed one juvenile male (carapace width 5.9mm, MNHN-B8733), and one male, one female and one juvenile (MCZ-IZ-CRU-9155). Guinot’s (1969b) “cotype” female measuring 16.5 × 10.0mm from station 36 is actually a male (see Material Examined below), although the gonopods are missing. During the examination of material by the first author in May 2023 in the MNHN bottle labelled as “Frevillea barbata” (MNHNB8733), he found only one small juvenile male measuring 7.8 × 5.9mm and labelled as the lectotype. In the card catalogues in MNHN (under MP B8733), only one cotype female measuring 16.5 × 10.0mm from the Gulf of Mexico is listed. The locality and station labels in the bottle match those given by A. MilneEdwards (1880), and they include the original hand-written labels at A. Milne-Edwards time from the Blake cruise. We are certain this specimen is not F.barbata, but F.rosaea (see below in Taxonomy section). The material in MCZ consists of one catalogued lot (MCZ-IZ-CRU-9155) with three specimens: one adult male (29.5 × 18.4mm), one badly damaged juvenile male (carapace width c. 9.0mm), and one adult female (27.3 × 17.2mm), all being listed in the labels as “cotypes” and in the database as “syntypes” (Figs1D, E; 2D). type Material.— The 26.0 × 17.0mm male of A. Milne-Edwards (1880) is the lectotype of Frevillea barbata because he did not identify a type specimen and did not indicate how many specimens he had (see above). This specimen is clearly the present MCZ male specimen measuring 29.5 × 18.4mm (MCZ-IZ-CRU-9155); it agrees very well with the original figures (A. Milne-Edwards& Bouvier 1923: pl.7, figs1, 2) (Figs1D; 2D). The present discrepancy in measurements can be explained by whether the carapace width was measured at the widest point of the external orbital teeth or across their bases; and if the length was taken medially, where the posterior margin is distinctly concave, or at its lateral part which is more concave. As noted above, the subsequent five specimens reported by A. Milne-Edwards& Bouvier (1923) should be now regarded as paralectotypes. Material exaMined.— Lectotype (by inference of holotype by Rathbun 1918: 26, as Goneplax barbata; and A. Milne-Edwards& Bouvier 1923: 336 as F.barbata). Mexico • ♂ (29.5 × 18.4mm); station 36, north of Alacran Reef, Campeche Bay, Yucatan; 84fathoms (= 154m); 23°13’0”N, 89°16’0”W; coll. USCGS; George S.Blake cruise; 19-24.I.1878; MCZ-IZ-CRU-9155. Paralectotypes. Mexico • 1 ♀ (27.3 × 17.2mm), 1 badly damaged juvenile ♂ (c. 9.0mm carapace width); same data as for lectotype; MCZ-IZ-CRU-9155) • 1 ♂ (16.5 × 10.0mm); same data as for lectotype; MNHN-IU-2014-7505) (= MNHN-B8733) • 1 ♀ (22.7× 15.7mm), 1 juvenile ♀ (7.9 × 5.0mm); same data as for lectotype; MNHN-IU-2014-7506) (= MNHN-B8733). G eoGrapHical distribution .— Western Atlantic region: Grenada and Gulf of Mexico coasts of Florida and Mexico. taxonoMy When the first author compared the specimens in the MNHN bottles now labelled as “Frevillea barbata” and “Frevillea rosaea” with the descriptions and the original figures of the species in A. Milne-Edwards (1880) and A. Milne-Edwards& Bouvier (1923), it was obvious that the specimens had been switched. In any case, F.rosaea was described only from two specimens, so the three specimens in the bottle clearly do not match. In separating F.rosaea from F.barbata, A. Milne-Edwards (1880: 15) noted that “Cette espèce se distingue de la précédente par sa carapace plus épaisse et moins élargie en avant; les bords latéraux étant presque parallèles. Le front est plus large et à bord plus droit. Les pédoncules oculaires sont plus gros et plus courts. L’angle postorbitaire est formé par une dent pointue, en arrière de laquelle existe un petit renflement tuberculiforme puis une épine hépatique courte mais acérée. Les pinces et les pattes ambulatoires sont disposées comme chez le Frevillea barbata.” [This species is distinguished from the preceding by its thicker carapace and less widened (narrower) in front; the side edges being nearly parallel. The front is wider and with a straighter edge. The eyestalks are larger and shorter. The postorbital angle is formed by a pointed tooth, behind which there is a small tuberculiform swelling and then a short but sharp hepatic spine. Claws and walking legs are arranged as in Frevillea barbata.]. Alphonse Milne-Edwards& Bouvier (1923: 337) added that while F.barbata and F.rosaea were close, “Aux observations précédentes j’ajouterai que les pédoncules oculaires de cette espèce sont très dilatés dans leur région cornéenne, que les deux échancrures du bord orbitaire supérieur sont très accentuées, surtout la plus interne et que les pattes ambulatoires semblent un peu moins fortes que celles du Frevillea barbata. A part quelques différences très légères, tous les autres caractères sont identiques à ceux de cette dernière espèce, du moins dans le type chargé d’œufs et dans le très jeune exemplaire qui m’ont été soumis.” [To the preceding observations I will add that the ocular peduncles of this species are very dilated in their corneal region, that the two indentations of the superior orbital edge are very accentuated, especially the most internal one and that the ambulatory legs seem a little less strong than those of the Frevillea barbata. Apart from a few very slight differences, all other characters are identical with those of the latter species, at least in the egg-laden type and in the very young specimen provided to me.]. The characters of the present MNHN juvenile male labelled as “Frevillea barbata” (7.8 × 5.9mm, MNHN-B8733) (Fig.3E-G) actually match those described and figured as F.rosaea by A. Milne-Edwards (1880) and A. MilneEdwards& Bouvier (1923) exactly. Conversely, the characters of the three MNHN specimens labelled as “Frevillea rosaea” (MNHN-B10152), match those of Frevillea barbata. How the specimens became switched in MNHN remains unknown and could have occurred during examination by researchers or other curatorial/digitisation processes. The second author had examined the MNHN material between 739 Taxonomy of Frevillea and description of Diuplax n. gen. ZOOSYSTEMA • 2024 • 46 (29) March and June 2006, and the material had already been mixed, as confirmed by notes and sketches of the two species made at the time. As such, the record of F.barbata (and F.rosaea) must be regarded as switched as they referred to both the types as well as the material they examined at that time. There are no problems with the MCZ specimens, with all the specimens of the two species agreeing with the original descriptions. The MNHN male specimen (16.5 × 10.0mm) now labelled as “Frevillea rosaea” (MNHN-B10152) actually closely matches what Guinot (1969b: pl.12 fig.2) figured as the MNHN “cotype” female of F.barbata from station 36 (no catalogue number indicated). They agree in measurements and the specimen agrees well in all physical features. We believe they are the same specimen. As such, after the present study of the literature and analysis of morphological characters for MNHN specimens of the two species in question, the specimens were returned to their correct jars. Frevillea barbata A. Milne-Edwards, 1880 is the type species of Frevillea (cf. Castro& Ng 2010), family Euryplacidae Stimpson, 1871 (see Rathbun 1918: 25). Frevillea rosaea A. Milne-Edwards, 1880 (Fig.3) Frevillea rosaea A. Milne-Edwards, 1880: 15.— A. Milne-Edwards& Bouvier 1923: 337, pl.6, fig.1.— Chace 1940: 47.— Guinot 1969b: 513; 1971: 1080 [list].— McLaughlin etal. 2005: 257.—Ng etal. 2008: 78.— Castro& Ng 2010: 56 (part). Frevillea rosae [sic] – Soto 1986: 3, 4, 33; 1991: 627. Frevillea rosea [sic] – Felder etal. 2009: 1081. Goneplax rosaea – Rathbun 1918: 25, 27.— Chace 1940: 47. Frevillea barbata – Castro& Ng 2010: 53 (part). (not F.barbata A. Milne-Edwards, 1880). History.— Frevillea rosaea was described from Blake’s station232 off St. Vincent, Lesser Antilles, from a depth of 88 fathoms (161m) (A. Milne-Edwards, 1880: 15). He provided measurements for one female, 20.0 × 15.0mm, but no type was indicated. For the species, Rathbun (1918: 27) stated: “type-locality, St. Vincent, 88, correctly 87, fathoms, station 232, Blake; holotype in Paris Mus.” and although she did not examine the specimen, her action constitutes the first valid designation of a name-bearing specimen or lectotype for the species. Alphonse Milne-Edwards& Bouvier (1923: 337) later commented that they had one type ovigerous female (has to be the one with the measurements 20.0 × 15.0mm) and one juvenile. They figured the dorsal features, including the carapace for the type female (A. Milne-Edwards& Bouvier 1923: pl.6, fig.1) (Fig.3A). In addition, they wrote: “A part quelques différences très légères, tous les autres caractères sont identiques à ceux de cette dernière espèce, du moins dans le type chargé d’œufs et dans le très jeune exemplaire qui m’ont été soumis.” [Apart from a few very slight differences, all the other characters are identical to those of the latter species, at least in the egg-bearing type and in the very young specimen passed to me.] (A. Milne-Edwards& Bouvier 1923: 337). These comments also constitute a name-bearing or lectotype designation, even if done after Rathbun (1918). Both Rathbun (1918) and A. Milne-Edwards& Bouvier (1923) apparently selected the same specimen to be the lectotype. Chace (1940: 47) subsequently recorded the species from Cuba. Castro& Ng (2010: 56) listed one female “lectotype” (22.7 × 15.7mm), one “paralectotype” male (16.3 × 10.1mm) and one pre-adult female “paralectotype” (7.9 × 5.0mm) (MNHN-B10152) for the species. During the examination of material by the first author in May 2023, in the MNHN bottle labelled as “Frevillea rosaea” (MNHN-B10152), he found three specimens: a male (16.5 × 10.0mm, without pleon and gonopods), a female (22.7 × 15.7mm), and a juvenile female (7.9 × 5.0mm) (Figs1F-H; 2A, B, E, F). The adult female (22.7× 15.7mm) (Figs1G; 2E) is labelled as the “lectotype” of the species, with the other two “paralectotypes.”. In the card catalogues in MNHN, three specimens are listed from St. Vincent, of which one juvenile is listed as the cotype (MP B10152). The locality labels in the bottle match those given by A. Milne-Edwards (1880), but there are no original labels from the Blake cruise. As discussed earlier under F.barbata, we are certain that these three specimens do not belong to F.rosaea but to F.barbata instead. The material in MCZ consists of only one ovigerous female specimen (22.1 × 15.4mm) (MCZ-IZ-CRU-9167) (Fig.3A-D) and is labelled as a “syntype” in the database. type Material.— On the basis of the published information, the 20.0 × 15.0mm female reported by A. Milne-Edwards (1880) is the lectotype of F.rosaea. This specimen is clearly the MCZ ovigerous female specimen measuring 22.1 × 15.4mm (MCZ-IZ-CRU-9167) (Fig.3A-D). The discrepancies in measurements are minor and can easily be accounted for by differences in how the measurements were made. Morphologically, it agrees very well with the original figures in A. Milne-Edwards& Bouvier (1923: pl.6 fig.1). The juvenile specimen reported by A. Milne-Edwards& Bouvier (1923) should be regarded as a paralectotype. Material exaMined.— Lectotype (by inference of holotype by Rathbun 1918: 27, as Goneplax rosaea; A. Milne-Edwards& Bouvier 1923: 337 as F.rosaea). Saint Vincent and the Grenadines • ovigerous ♀ (22.1 × 15.4mm); station232; off St. Vincent; 88fathoms (=161m); 13°06’45”N, 61°06’55”W; coll. USCGS; George S. Blake cruise; 21.II.1879; MCZ-IZ-CRU-9167. Paralectotype. Saint Vincent and the Grenadines • 1 juvenile ♂ (7.8 × 5.9mm); same data as lectotype; MNHN-IU-2014-19822 (= MNHN-B10152). GeoGrapHical distribution.— Western Atlantic region: Cuba and St. Vincent. taxonoMy See the earlier discussion on the confusion of the types of F.barbata and F.rosaea. Frevillea rosaea A. Milne-Edwards, 1880 is included in Frevillea s.str. as redefined by Castro& Ng (2010), family Euryplacidae Stimpson, 1871. Family pseudorHoMbilidae Alcock, 1900 Genus Trapezioplax Guinot, 1969 Trapezioplax Guinot, 1969: 712. type species. — Frevillea tridentata A. Milne-Edwards, 1880, by original designation; gender feminine. 746 ZOOSYSTEMA • 2024 • 46 (29) Ng P. K. L. et al. male pl 2 (fig.72), longer than the pl 1. In sigsbei (fig.63), as in rhomboides (fig.64), the male orifice opens on the coxa of p5 but, as a result of the beginning of the union of sternites 8 and 7, the penis is in an imperfectly closed gutter, formed between these two regions. It should be noted that in rhomboides, the lateral portion of sternite 8 not covered by the abdomen is important and is widely inserted between the entire basilar, narrow part of the abdomen (segments 1 and 2) and the coxae of p5; on the other hand, in sigsbei, the first abdominal segments, more extended, occupy practically all the space between the coxae of p5, with the exception of a small part of sternite 8 which is left uncovered. Moreover, it does not seem that in sigsbei the flagellum of pl 2, which is curved, is bifid as in G.rhomboides.] Frevillea sigsbei A. Milne-Edwards, 1880 is clearly a member of Goneplacidae MacLeay, 1838, s.str. (cf. Castro 2007). Comparing the specimens of F.sigsbei also shows that Guinot’s (1969b) doubts about transferring it to Goneplax are justified. The differences in the pleon, sternal and gonopodal structures, as well as differences in the carapace and chelipeds with Goneplax s.str. argue for treating F.sigsbei as a separate new genus. It is here made the type species for a new genus, Diuplax n.gen. Acknowledgements We are grateful to museum technician Laura Flamme (under MNHN Projet: RECOLNAT (ANR-11-INBS-0004) who first highlighted the problems of the types of F.barbata and F.rosaea to the second author. Thanks are due to Adam Baldinger (MCZ) for checking on the specimens in MCZ, and to Alana Rivera (Curatorial Assistant) for taking the photographs of the material. We would also like to thank Laure Corbari (Curator of Crustacea, MNHN) for access to the ABC DE FG fig. 7. — Goneplax rhomboides (Linnaeus, 1758), ♂ (36.5 × 22.6 mm) (ZRC 2010.0069), Scotland. A, dorsal view of carapace; B, frontal view of cephalothorax; C, left third maxilliped; D, anterior thoracic sternum and pleon; E, posterior thoracic sternum and pleon; F, right merus of cheliped (inner view); G, left fourth ambulatory leg. Credits: photographs by P. K. L. Ng. 747 Taxonomy of Frevillea and description of Diuplax n. gen. ZOOSYSTEMA • 2024 • 46 (29) collections. The first and second authors also thank Danièle Guinot for her hospitality and advice on goneplacoids during our visits to MNHN, as well as her help with the manuscript. She and Shane Ahyong kindly reviewed the manuscript, for which we are most grateful. REFERENCES abele l. G. & kiM W. 1986.— An Illustrated Guide of the Marine Decapod Crustaceans of Florida. Department of Environmental Regulation State of Florida and Florida State University Tallahassee Technical Series 8 (1) Parts 1, 2, 760p. Alcock a. 1900.— Materials for a carcinological fauna of India. No. 6. The Brachyura Catometopa, or Grapsoidea. Journal on the Asiatic Society of Bengal 69 (2): 279-456. https://doi.org/10.5962/ bhl.title.15344 borradaile l. a. 1916.— Decapoda Crustacea part 1, in British Antarctic (“Terra Nova”) Expedition 1910. Natural History Reports Zoology British Museum (Natural History) London vol.3 Arthropoda (2): 75-110. https://www.biodiversitylibrary.org/ bibliography/111654 boscHi e. 2000.— Species of decapod crustaceans and their distribution in the American marine zoogeographic provinces. Revista de Investigación y Desarrollo Pesquero 13: 1-136. castro p. 2007.— A reappraisal of the family Goneplacidae MacLeay 1838 (Crustacea Decapoda Brachyura) and revision of the subfamily Goneplacinae with the description of 10 new genera and 18 new species. Zoosystema 29 (4): 609774. https://www.biodiversitylibrary.org/page/7637388 castro p. & nG p. k. l. 2010.— Revision of the family Euryplacidae Stimpson 1871 (Crustacea: Decapoda: Brachyura: Goneplacoidea). Zootaxa 2375: 1-130. https://doi.org/10.11646/zootaxa.2375.1.1 cHace F. a. 1940.— The brachyuran crabs in Reports on the scientific results of the Atlantis Expeditions to the West Indies under the joint auspices of the University of Havana and Harvard University. Torreia 4: 1-67. davie p. J. F., Guinot d. & nG p. k. l. 2015.— Anatomy and functional morphology of Brachyura (Chapter 71-2), in c astro p., d avie p. J. F., G uinot d., s cHraM F. r. & von vaupel klein J. C. (eds), Decapoda: Brachyura, Treatise on Zoology– Anatomy, Taxonomy, Biology. Vol. 9C-I. Brill, Leiden and Boston: 11-163. Felder d. l., Álvarez F., Goy J. W. & leMaitre r. 2009.— Decapoda (Crustacea) of the Gulf of Mexico with comments on the Amphionidacea. Chapter 59, in t unnell J. W. J r . Felder d. l. & earle s. a. (eds), Gulf of Mexico Origin Waters and Biota vol. 1 Biodiversity Harte Research Institute of Gulf of Mexico Studies Series Texas A&M University Press Texas USA: 1019-1104. Guinot d. 1969a.— Recherches préliminaires sur les groupements naturels chez les Crustacés Décapodes Brachyoures. VII Les Goneplacidae. Bulletin du Muséum national d’Histoire naturelle Paris sér. 2 41(1): 241-265, pl.2. https://www.biodiversitylibrary. org/page/55599183 G uinot d. 1969b.— Recherches préliminaires sur les groupements naturels chez les Crustacés Décapodes Brachyoures VII. Les Goneplacidae (suite). Bulletin du Muséum national d’Histoire naturelle sér. 2, 41 (2): 507-528, pl.2. https://www.biodiversitylibrary.org/page/55599454 G uinot d. 1969c.— Recherches préliminaires sur les groupements naturels chez les Crustacés Décapodes Brachyoures VII. Les Goneplacidae (suite et fin). Bulletin du Muséum national d’Histoire naturelle sér. 2, 41: 688-724, pls3-5. https://www. biodiversitylibrary.org/page/55599642 Guinot d. 1971.— Recherches préliminaires sur les groupements naturels chez les Crustacés Décapodes Brachyoures VIII. Synthèse et bibliographie. Bulletin du Muséum national d’Histoire naturelle sér. 2, 42(5) [1970]: 1063-1090. https://www.biodiversitylibrary. org/page/56079257 Guinot d. & castro p. 2007.— A new species of Goneplax Leach 1814 (Crustacea Decapoda Brachyura Goneplacidae) from the south Atlantic and western limits of the Indo-West Pacific region long confused with G.rhomboides (Linnaeus 1758). Zootaxa 1577: 17-31. https://doi.org/10.11646/zootaxa.1577.1.3 G uinot d., t avares M. & c astro p. 2013.— Significance of the sexual openings and supplementary structures on the phylogeny of brachyuran crabs (Crustacea Decapoda Brachyura) with new nomina for higher-ranked podotreme taxa. Zootaxa 3665 (1): 1-414. https://doi.org/10.11646/zootaxa.3665.1.1 HerMoso-salazar M. & arvizu-coyotzi k. 2015.— Crustáceos del Sistema Arrecifal Veracruzano, in Granados-barba a., ortizl ozano l. d., s alas -M onreal d. & G onzalez -G Ándara c. (eds), Aportes al conocimiento del Sistema Arrecifal Veracruzano: Hacia el Corredor Arrecifal del Suroeste del Golfo de México. Universidad Veracruzana Vera Cruz Mexico: 47-74. iczn, i nternational c oMMission on z ooloGical n oMen - clature. 1999.— International Code of Zoological Nomenclature. International Commission of Zoological Nomenclature. Fourth Edition. Adopted by the XXI General Assembly of the International Union of Biological Sciences. International Trust for Zoological Nomenclature in association with the British Museum (Natural History) London 338p. https://www.iczn. org/the-code/the-code-online/ l eacH W. e. 1814.— Crustaceology, in The Edinburgh Encyclopaedia conducted by David Brewster LLD vol. 7 (2) pp. 385-487, 765766 (plate legend) (plate CCXXI issued with vol. 9 (1) in 1815). Edinburgh. https://www.biodiversitylibrary.org/page/37187274 l innaeus c. 1758.— Systema Naturae per Regna Tria Naturae Secundum Classes Ordines Genera Species cum Characteribus Differentiis Synonymis Locis Tomus I. Laurentii Salvii, Holmi., [iv] + 824p. https://doi.org/10.5962/bhl.title.542 Macleay W. s. 1838.— On the Brachyurous Decapod Crustacea. Brought from the Cape by Dr. Smith, in s MitH a., Illustrations of the Zoology of South Africa; consisting chiefly of figures and descriptions of the objects of natural history collected during an expedition into the interior of South Africa in the years 1834 1835 and 1836; fitted out by ‘The Cape of Good Hope Association for Exploring Central Africa’: together with a summary of African Zoology and an inquiry into the geographical ranges of species in that quarter of the globe published under the Authority of the Lords Commissioners of Her Majesty’s Treasury Invertebratae. IV [1849], Smith Elder& Co. London: 53-71, pls2, 3. https://www.biodiversitylibrary. org/page/11059737 MclauGHlin p. a., caMp d. k., anGel M. v., bousField e. l., b runel p., b rusca r. c., c adien d., c oHen a. c., c onlan k., eldredGe l. G., Felder d. l., Goy J. W., Haney t., Hann b., Heard r. W., Hendrickx e. a., Hobbs H. H., HolsinGer J. r., kensley b., laubitz d. r., lecroy s. e., leMaitre r., Maddocks r. F., Martin J. W., nikkelsen p., nelson e., neWMan W. a., overstreet r. M., poly W. J., price W. W., reid J. W., robertson a., roGers d. c., ross a., scHotte M., s cHraM F. r., s HiH c.-t., W atlinG l., W ilson G. d. F. & turGeon d. d. 2005.— Common and scientific names of aquatic invertebrates from the United States and Canada: Crustaceans. American Fisheries Society, Bethesda, Maryland, USA, Special Publication 31: xiii + 545. ark:/13960/t7wn09t95 M ilne -e dWards a. 1880.— Études préliminaires sur les Crustacés 1ere partie, in Reports on the results of dredging under the supervision of Alexander Agassiz in the Gulf of Mexico and in the Caribbean Sea 1877 ’78 ‘79 by the U.S. Coast Survey Steamer “Blake” Lieut.-Commander C.D. Sigsbee U.S.N. and Commander J.R. Bartlett U.S.N. commanding VIII. Bulletin of the Museum of Comparative Zoology at Harvard College 8: 1-68, pls1, 2. https://www.biodiversitylibrary.org/page/30184918 748 ZOOSYSTEMA • 2024 • 46 (29) Ng P. K. L. et al. M ilne -e dWards a. & b ouvier e.-l. 1923.— Les Porcellanides et des Brachyoures, in Reports on the results of dredging under the supervision of Alexander Agassiz in the Gulf of Mexico (187778) in the Caribbean Sea (1878-79) and along the Atlantic coast of the United States (1880) by the U.S. Coast Survey Steamer “Blake” Lieut.-Comm. C.D. Sigsbee U.S.N. and Commander J.R. Bartlett U.S.N. commanding XLVII. Memoirs of the Museum of Comparative Zoology at Harvard College 47 (4): 281-395, pls1-12. https://www.biodiversitylibrary.org/page/4368457 nG p. k. l., Guinot d. & davie p. J. F. 2008.— Systema Brachyurorum: Part I. An annotated checklist of extant brachyuran crabs of the world. Raffles Bulletin of Zoology Supplement 17: 1-286. nizinski M. 2003.— Annotated checklist of decapod crustaceans of Atlantic coastal and continental shelf waters of the U.S. Proceedings of the Biological Society of Washington 116: 96-157. https:// www.biodiversitylibrary.org/page/34564867 poupin J. 1994.— Faune marine profonde des Antilles françaises. Récoltes du navire Polka faites en 1993. Études et Thèses 1-79, pls1-5. poWers l. W. 1977.— A catalogue and bibliography to the crabs (Brachyura) of the Gulf of Mexico. Contributions in Marine Science [University of Texas Marine Science Institute] Supplement 20: 1-190. ratHbun M. J. 1898.— The Brachyura of the biological expedition to the Florida Keys and the Bahamas in 1893. Bulletin of the Laboratories of Natural History of the State University of Iowa 4 (3): 250-294, pls1-9. https://www.biodiversitylibrary.org/ page/15405204 ratHbun M. J. 1904.— Les crabs d’eau douce, (Potamonidae). Nouvelles Archives du Muséum national d’Histoire naturelle, Série4, 6: 225-312, pls 9-18. ratHbun M. J. 1918.— The grapsoid crabs of America. Bulletin of the United States National Museum 97: xxii + 461, pls1-161. https://www.biodiversitylibrary.org/page/7637388 soto l. a. 1985.— Distributional patterns of deep-water brachyuran crabs in the Straits of Florida. Journal of Crustacean Biology 5 (3): 480-499. https://doi.org/10.2307/1547920 soto l. a. 1986.— Deep-water brachyuran crabs of the Straits of Florida (Crustacea Decapoda). Anales del Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México 13 (1): 1-68. soto l. a. 1991.— Faunal zonation of the deep-water brachyuran crabs in the Straits of Florida. Bulletin of Marine Science 49 (1-2): 623-637. s tiMpson W. 1871.— Brachyura. Preliminary report on the Crustacea dredged in the Gulf Stream in the Straits of Florida, by L. F. Pourtales, Assist. U.S. Coast Surveys, Part 1. Bulletin of the Museum of Comparative Zoology at Harvard College 2: 109-160. https://www.biodiversitylibrary.org/page/6313618 tHoMa b. p., scHubart c. d. & Felder d. l. 2009.— Molecular phylogeny of Western Atlantic representatives of the genus Hexapanopeus (Decapoda: Brachyura: Panopeidae), in Martin J., crandall J. W. k. & Felder d. l. (eds). Decapod Crustacean Phylogenetics. Crustacean Issues 18: 551-565. tHoMa b. p., Guinot d. & Felder d. l. 2014.— Evolutionary relationships among American mud crabs (Crustacea: Decapoda: Brachyura: Xanthoidea) inferred from nuclear and mitochondrial markers. Zoological Journal of the Linnean Society 170: 86-109. https://doi.org/10.1111/zoj12093 WilliaMs a. b. 1984.— Shrimps Lobsters, and Crabs of the Atlantic Coast of the Eastern United States Maine to Florida. Smithsonian Institution Press Washington D. C. xviii + 550p. https://doi. org/10.2307/1352125 WilliaMs a. b., Mccloskey l. r. & Gray i. e. 1968.— New records of brachyuran decapod crustaceans from the continental shelf off North Carolina U.S.A. Crustaceana 15 (1): 41-66. https://doi.org/10.1163/156854068X00755 Submitted on15December 2023; accepted on 15April 2024; published on 12November 2024.