Eryma westphali Schweigert, Dietl & Röper, 2000

Devillez, Julien & Charbonnier, Sylvain, 2021, Review of the Late Jurassic erymoid lobsters (Crustacea: Decapoda), Geodiversitas 43 (2), pp. 25-73 : 40-42

Eryma westphali Schweigert, Dietl & Röper, 2000

( Fig. 7 G-J)

Eryma westphali Schweigert, Dietl & Röper, 2000: 6 , pl. 3, figs 1-3. — Dietl & Schweigert 2001: 53, 110, fig. 85. — Garassino & Schweigert 2006: 8. — Feldmann & Titus 2006: 64.

Galicia westphali – Schweitzer et al. 2010: 25. — Hyžný et al. 2015: 375.

TYPE MATERIAL. — Holotype SMNS 24227 . TYPE LOCALITY. — Nusplingen , Baden-Württemberg, Germany. TYPE AGE. — Kimmeridgian .

DESCRIPTION

Carapace

Short, spiny rostrum; fusiform intercalated plate; deep, wide cervical groove, joined to dorsal margin and to antennal groove; deep antennal groove; short, sub-horizontal gastroorbital groove; postcervical groove slightly curved forward, not joined to dorsal margin, joined to branchiocardiac groove at carapace mid-height, with a short ventral extension; branchiocardiac groove dorsally deep, narrowing in its ventral part, not joined to dorsal margin, joined to hepatic groove; hepatic groove concavo-convex.

Pleon and uropods

Somites with subtriangular pleurites, with a bulge on their basis; wide rounded uropods; uropodal endopods with a longitudinal carina; uropodal exopods with a small spine on external margin.

Thoracic appendages

Chelate P1; P1 propodus subrectangular, narrow and strongly elongated; P1 fingers shorter than propodus, slender, almost

straight or slightly curved inward, with a terminal hook; occlusal margin without teeth; P1 carpus short, subtriangular; thin P2-P5; P2-P3 chelate.

Ornamentation

Carapace with a dense, heterogeneous ornamentation; gastric and cardiac regions covered by tubercles; antennal, hepatic, and branchial regions covered by small rounded depressions; presence of an orbital spine; tergites and pleurites densely covered by small rounded depressions; presence of a strong antennal spine; smooth P1-P5.

DISCUSSION

This species is only known by three specimens. It is assigned to Eryma because of its typical carapace groove pattern (short gastro-orbital groove, postcervical and branchiocardiac grooves joined at carapace mid-height, hepatic groove concavo-convex) and the shape of the P1 chelae (elongated propodus, subrectangular, with slender fingers progressively narrowing to their distal extremity).

Among the erymid lobsters, Eryma westphali is the only species with heterochelous P1 chelae on a same specimen. Left propodus is more elongated and narrower than the right one, and the left fingers are straight and short while the right ones are curved and slightly longer ( Fig. 7I, J ). The strongly elongated and narrow P1 propodus with relatively short fingers of E. westphali is characteristic of the species. Only Eryma veltheimii ( Münster, 1839) have P1 with a very long propodus, but it is clearly wider.

In E. westphali the branchial region is dorsally shorter than in E. georgeii , E. jungostrix , E. lerasi , E. modestiforme , and E. ventrosum . Contrary to E. lerasi and E. quadriverrucatum , E. westphali exhibits a ventral extension of the postcervical groove. Moreover, the dichotomy of the ornamentation of the carapace between the gastric and cardiac regions, covered by tubercles, and the remaining regions of E. westphali , covered by small depressions, is unique among the genus.

Figures

FIG. 7. — Eryma major Oppel, 1861, Eryma veltheimii (Münster, 1839) and Eryma westphali Schweigert, Dietl & Röper, 2000 from the Kimmeridgian of Germany: A, holotype SMNS 3682 of E. major from Egesheimer;B, specimen SMNS 67655 of E. major from Gerhausen; C, specimen SMNS 64371 of E. major from Nusplingen; D-F, holotype BSPG AS VII 186 of E. veltheimii from Kehlheim: part (D), counter-part (E), details of telson and uropods (F); G-J, holotype SMNS 24227 of E. westphali from Nusplingen: general view (G), schema of the carapace (H), schema of left chela (I), schema of right chela (J); C, specimen SMNS 63733 from Nusplingen. Abbreviations: a, branchiocardiac; as, antennal spine; b, antennal groove; b1, hepatic groove; c, postcervical; d, gastro-orbital groove; e1e, cervical groove; ip, intercalated plate. Black arrows show the spines. Photographs and line drawings: J. Devillez. Scale bars: 1 cm.