Eryma vocontii, Devillez & Charbonnier & Hyžný & Leroy, 2016

Devillez, Julien, Charbonnier, Sylvain, Hyžný, Matúš & Leroy, Lucien, 2016, Review of the Early Cretaceous erymid lobsters (Crustacea: Decapoda) from the Western Tethys, Geodiversitas 38 (4), pp. 515-541 : 518-520

Eryma vocontii n. sp.

( Fig. 4 A-F)

TYPE MATERIAL. — Holotype MNHN.F.A57457 (carapace); paratype MNHN.F.A57458 (P1 chela) (Clément coll.).

TYPE LOCALITY. — Rosans , Hautes-Alpes department, Provence- Alpes-Côte d’Azur region, southeastern France.

TYPE AGE. — Albian, Early Cretaceous.

ETYMOLOGY. — The specific epithet refers to the Voconces, a prealpine federation of Gaul people.

DESCRIPTION

Subcylindrical carapace (holotype: CL = 23 mm, CH = 10 mm); rostrum not preserved; subvertical cervical groove, dorsally wide and deep, strongly narrowing under gastroorbital groove, joined to antennal groove; cephalic region with oblique orbital row of tubercles (antennal row poorly preserved); narrow, curved antennal groove; short, wide gastro-orbital groove, originating as a slight median inflexion of cervical groove; straight, wide and deep postcervical groove, joined to dorsal margin and joined medially to branchiocardiac groove, extended with a short ventral extension; straight, strongly inclined branchiocardiac groove with narrow dorsal part, joined to dorsal margin and to hepatic groove; narrow and shallow hepatic groove, concavo-convex; strongly raised ω and χ bulges; sub-rectangular χ bulge dorsally limited by shallow depression running between hepatic and branchiocardiac grooves; rounded ω bulge; inferior groove poorly preserved; carapace uniformly covered with fine tubercles preceded by crescent-shaped pits (pits deeper in branchial region); P1 chela with compressed trapezoidal propodus; dorsal surface of P1 palm with median longitudinal bulge surrounded by two longitudinal depressions parallel to lateral margins; P1 palm with narrow dactylar bulge, posteriorly delimited by a shallow groove; long, straight fingers, gradually narrowing to distal extremity; index wider than dactylus; dactylus with small basal depression; occlusal margins slightly denticulate; propodus covered with fine tubercles; fingers covered with punctations. P1 belongs to claw form II.

DISCUSSION

Paratype MNHN.F.A57458 ( Fig. 4E, F ) corresponds to an isolated right P1 chela collected in the same bed than the carapace MNHN.F.A57457 ( Fig. 4 A-D). Based on this report, we suggest that the association carapace-chela comes from the same species and we include the chela in the specific description.

Eryma vocontii n. sp. is assigned to Eryma Meyer, 1840 based on its typical carapace groove pattern and its tuberculate orbital row in cephalic region. Eryma vocontii n. sp. differs from the three other Early Cretaceous species, Eryma glaessneri ( Van Straelen, 1936) , Eryma nippon Karasawa et al., 2008 , and Eryma sulcatum Harbort, 1905 by its carapace groove pattern with: 1) subvertical cervical groove (strongly inclined in the three other species); 2) straight, deep postcervical groove, slightly inclined and joined to dorsal margin (sinuous and strongly inclined in E. glaessneri ; shallow, slightly convex forward and not joined to dorsal margin in E. sulcatum ); 3) straight, shallow and strongly inflected branchiocardiac groove (sinuous in E. glaessneri ; slightly inflected in E. sulcatum ); and (4) short gastro-orbital groove (long in E. glaessneri ). Moreover, E. glaessneri exhibits a relatively massive carapace with inflated branchial region (not inflated in Eryma vocontii n. sp.) and a flat attatchment site of adductor testis muscle (inflated in Eryma vocontii n. sp.), and Eryma sulcatum exhibits a post-orbital area (absent in Eryma vocontii n. sp.). Eryma nippon has a circular χ bulge while it is sub-rectangular in Eryma vocontii n. sp. Eryma vocontii n. sp. has a carapace with uniform fine ornamentation whereas the carapaces of E. glaessneri and E. sulcatum show heterogeneous ornamentation (coarse tubercles in cardiac and cephalic regions in E. glaessneri ; smaller and more dense ornamentation in branchial region with regard to the rest of carapace and row of coarse tubercles parallel to intercalated plate in E. sulcatum ). Eryma nippon has a homogeneous ornamentation but it is made of coarse tubercles (small tubercles in Eryma vocontii n. sp.).

Other Cretaceous Eryma species were described from North America ( Eryma americanum Rathbun, 1923 , Eryma flectum Rathbun, 1926 , and Eryma stantoni Rathbun, 1935 ) and from Lebanon ( Eryma cretaceum Roger, 1946 ). After careful examination of the figures presented by Rathbun (1923, 1926, 1935) and according to Förster (1966: 125), we consider that the American species (largely based on fragmentary specimens) are not representatives of Erymidae . As for the Lebanese species, we follow Charbonnier et al. (in press) with the placement in Pustulina . In conclusion, Eryma vocontii n. sp. is the hitherto youngest occurrence of the genus Eryma .

Figures

FIG. 4. — Species of Eryma Meyer,1840 from Western Europe.A-D, holotype MNHN.F.A57457 (Clément coll.) of Eryma vocontii n. sp.from the Albian of Rosans,France: right lateral view (A), line drawing (B), left lateral (C) and dorsal (D) views; E-F, paratype MNHN.F.A57458 (Clément coll.) of Eryma vocontii n. sp.: dorsal view of right P1 chela (E) and line drawing (F); G, H, cast of the holotype MNHN.F.R10204 of Eryma glaessneri (Van Straelen,1936) from the Hauterivian of Escragnolles,France:left lateral view (G) and line drawing (H); I-L, neotype herein designated SM B11437 of Eryma sulcatum Harbort, 1905 from the Hauterivian of Speeton, United Kingdom: left lateral view (I), dorsal view (K) and line drawings (J, L). Abbreviations:a, branchiocardiac groove; b, antennal groove; b1, hepatic groove; c, postcervical groove; d, gastro-orbital groove; e1e, cervical groove; i, inferior groove; ip, intercalated plate; PoA, post-orbital area; ω, attachment site of mandibular muscle; χ, attachment site of adductor testis muscle. Photographs:L. Cazes (A-D,G), J. Devillez (I, K). Line drawings:J. Devillez. Scale bars: A-F,5 mm; G-L, 10 mm