Eryma Meyer, 1840

Devillez, Julien & Charbonnier, Sylvain, 2021, Review of the Late Jurassic erymoid lobsters (Crustacea: Decapoda), Geodiversitas 43 (2), pp. 25-73 : 28

Genus Eryma Meyer, 1840

( Fig. 1 C-E)

Eryma Meyer, 1840a: 587 . — Oppel 1862: 20. — Zittel 1885: 693. — Méchin 1901: 74. — Van Straelen 1925: 233. — Rathbun 1926: 127. — Secrétan 1964: 61; 1984: 516. — Förster 1966: 88. — Glaessner 1969: 455. — Aguirre-Urreta & Ramos 1981: 610. — Aguirre-Urreta 1989: 513. — Crônier & Courville 2004: 1004. — Feldmann & Titus 2006: 63. — Feldmann & Haggart 2007: 1792. — Hyžný et al. 2015: 375. — Feldmann et al. 2015: 1. — Devillez et al. 2016: 518 . — Devillez & Charbonnier 2017: 3.

Bolina Münster, 1839 sensu Étallon (1859: 192 ; non Mertens, 1833).

Klytia Meyer, 1840b: 19 . — Glaessner 1969: 456.

Protoclytiopsis Birshtein, 1958: 477 . — Förster 1966: 86. — Feldmann et al. 2015: 10.

Galicia Garassino & Krobicki, 2002: 55 . — Feldmann et al. 2015: 3.

Clytia – Beurlen 1928: 165.

TYPE SPECIES. — Macrourites modestiformis Schlotheim, 1822 , by subsequent designation of Glaessner (1929).

DIAGNOSIS BY Devillez & Charbonnier (2019). — Fusiform intercalated plate; deep cervical groove, strongly inclined dorsally, joined to dorsal

margin and to antennal groove; short gastro-orbital groove, originating as a slight median inflexion of the cervical groove; postcervical groove joined to branchiocardiac groove at carapace mid-height; branchiocardiac groove usually strongly inclined, joined to the posterior extremity of hepatic groove; hepatic groove concavo-convex, joined to cervical groove; inferior groove convex posteriorly, joined to hepatic groove and to ventral margin;ω area usually inflated; cephalic region usually with an orbital row and with strong orbital and antennal spines; chelate P1-P3; P1 chelae without prominent spines and with an homogeneous ornamentation; P1 propodus compressed dorso-ventrally with narrow inner and outer margins, with a narrow dactylar bulge; P1 fingers usually longer than propodus, equal in length, progressively narrowing to their distal extremity; index wider than dactylus; P1 chelae (form I; Fig. 1D ) with a short rectangular propodus, straight fingers, slightly longer than propodus; P1 chelae (form II; Fig. 1E ) with an elongated subrectangular or trapezoidal propodus, bearing fingers quite longer than propodus, usually curved inward.

DISCUSSION

In the literature, two species only known by isolated P1 chelae found in the Oxfordian of United Kingdom were wrongly assigned to Eryma : Eryma pulchellum Carter, 1886 and Eryma stricklandi ( Phillips, 1871) . The short propodus bearing short fingers slightly curved outward indicates that E. pulchellum does not belong to Erymoidea . Förster (1966) proposed to assign this species to Magila Münster, 1839 . The P1 chelae of E. stricklandi exhibits elongated propodus and fingers, that are slender and of opposite curvatures – so their distal extremities are convergent – and an index longer than dactylus. Such morphology is not consistent with any known erymoid lobster. So, E. stricklandi does not belong to Erymoidea .

De Gregorio (1884) described Eryma rinellincolum on a P1 propodus from the Tithonian near Palermo ( Italy). This specimen is not located and has never been figured. It is also insufficiently described ( Förster 1966). Because it is impossible to clearly determine the genus or the familly of this specimen, we consider it as nomen dubium.

Some specimens of Eryma mandelslohi (Meyer, 1840) from the Oxfordian of France and Switzerland are stored in the collections of the MNHN and the NMB. The age of this species is Callovian (Middle Jurassic). Devillez & Charbonnier (2019) have redescribed it in the review of the Early and Middle Jurassic erymids, so it will not be discussed here.

To shorten the discussions, the comparisons of the species of Eryma described below are restricted to the other Late Jurassic species.

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.