Enoploclytia M’Coy, 1849

Devillez, Julien & Charbonnier, Sylvain, 2021, Review of the Late Jurassic erymoid lobsters (Crustacea: Decapoda), Geodiversitas 43 (2), pp. 25-73 : 64

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.

Figures

FIG. 1. — Carapace and P1 chela morphologies of the Late Jurassic erymoids: A, regions of the carapace; B, morphology of a chela of the first pair of pereiopods; C, typical carapace groove pattern of Eryma; D, form I of chela of the first pair of pereiopods of Eryma; E, form II of chela of the first pair of pereiopods of Eryma; F, typical carapace groove pattern of Palaeastacus; G, typical chela of the first pair of pereiopods of Palaeastacus; H, typical carapace groove pattern of Pustulina; I, typical chela of the first pair of pereiopods of Pustulina; J, typical carapace groove pattern of Stenodactylina; K, form I of chela of the first pair of pereiopods of Stenodactylina; L, form II of chela of the first pair of pereiopods of Stenodactylina; F, typical carapace groove pattern of Enoploclytia; G, typical chela of the first pair of pereiopods of Enoploclytia. Abbreviations: a, branchiocardiac groove; ar, antennal region; b, antennal groove; b1, hepatic groove; br, branchial region; c, postcervical groove; cr, cardiac region; d, gastro-orbital groove; e1e, cervical groove; gr, gastric region; hr, hepatic region; i, inferior groove; ip, intercalated plate; PoA, post-orbital area; pr, pterygostomial region; χ, attachment site of adductor testis muscle; ω, attachment site of mandibular muscle. Line drawings: J. Devillez.

FIG. 18. — Enoploclytia sp.from the Oxfordian of Cricqueboeuf (France):A, specimen MNHN.F.A66892; B, detail of the carapace whitened with ammonium chloride; C, schema of the carapace.Abbreviations:a, branchiocardiac groove;as, antennal spine;b, antennal groove; b1, hepatic groove; c, postcervical groove; d, gastro-orbital groove; e1e, cervical groove; i, inferior groove. Photographs: A, P. Loubry; B, L. Cazes. Line drawing: J. Devillez. Scale bars: 1 cm.