Enoploclytia Mesozoique, M'Coy 1849

Genus Enoploclytia M’Coy, 1849

(Fig. 1 M-N)

Enoploclytia M’Coy, 1849: 330; 1854: 137. — Zittel 1885: 694. — Fritsch & Kafka 1887: 27. — Van Straelen 1925: 278. — Beurlen 1928: 164. — Rathbun 1926: 128. — Secrétan 1964: 81. — Förster 1966: 146. — Taylor 1979: 25. — Aguirre-Urreta 1989: 514. — Feldmann et al. 2015: 3. — Devillez et al. 2016: 530, fig. 1I-J; 2017: 786, fig. 4A-B; 2018: 144, fig. 2A-B.

Enoploclytia Enoploclytia – Mertin 1941: 160. — Glaessner 1969: 455.

TYPE SPECIES. — Astacus leachii Mantell, 1822, by original designation.

DIAGNOSIS BY Devillez et al. (2018). — Fusiform intercalated plate; wide, deep cervical groove, joined to dorsal margin and to antennal groove; long, wide gastro-orbital groove originating as a median inflexion of cervical groove, delimiting two gastroorbital lobes; sinuous postcervical groove, joined to dorsal margin and to hepatic groove, with ventral extension at carapace mid-height; short branchio-cardiac groove, interrupted in upper part of carapace, joined to dorsal margin, not joined to postcervical groove; concavo-convex hepatic groove, joined to cervical groove; prominent ω and χ bulges; inferior groove convex posteriorly, joined to hepatic groove; carapace with heterogeneous coarse ornamentation; massive globose P1 propodus, rounded in transversal section; long and thin P1 fingers (straight in dorsal view); occlusal margins armed with sharp and slender tooth; P1 merus with strong, prominent distal process at extern side of its ventral extremity.

DISCUSSION

Recently, Devillez et al. (2018) reported a specimen identified as Enoploclytia sp. from the Oxfordian of France (Fig. 18). Despite its poor preservation, this fossil exhibits the typical carapace groove pattern of the genus: elongated gastro-orbital groove, with two divergent distal branches, a sinuous postcervical groove joined to the posterior extremity of the hepatic groove and not joined to the branchiocardiac groove, which is short and interrupted in the branchial region (Fig. 18C). This specimen is the oldest occurrence of Enoploclytia, and the only known in the Jurassic. Indeed, Enoploclytia is more typical of the Cretaceous.