Eryma jungostrix Feldmann & Titus, 2006

Devillez, Julien & Charbonnier, Sylvain, 2021, Review of the Late Jurassic erymoid lobsters (Crustacea: Decapoda), Geodiversitas 43 (2), pp. 25-73 : 30-32

Eryma jungostrix Feldmann & Titus, 2006

( Fig. 2 E-G)

Eryma jungostrix Feldmann & Titus, 2006: 64 , figs 3-4. — Garassino & Schweigert 2006: 8. — Feldmann & Haggart 2007: 1792, 1794. — Schweitzer et al. 2010: 24. — Devillez et al. 2017: 792.

TYPE MATERIAL. — Holotype USNM 530027.

TYPE LOCALITY. — NE ¼, SW¼, SW ¼, Sec. 4, T5S, R24E (Salt Lake Meridian), Utah, United States.

TYPE AGE. — Oxfordian.

DESCRIPTION

Carapace

Sub-cylindrical carapace; short, spiny rostrum;fusiform intercalated plate; narrow, inflated post-orbital area; high pterygostomial region;deep and wide cervical groove, strongly inflected at carapace mid-height, joined to dorsal margin and to antennal groove; shallow and narrow antennal groove; short and narrow gastro-orbital groove, originating as strong median inflexion of cervical groove; deep and wide postcervical groove, almost straight, strongly inclined, joined to dorsal margin and joined to branchiocardiac groove at carapace mid-height, with a short ventral extension; deep branchiocardiac groove, subparallel to postcervical groove, almost straight dorsally, slightly curved towards its junction to the hepatic groove, strongly inclined, joined to dorsal margin and to hepatic groove; deep and wide hepatic groove, concavo-convex, joined to cervical groove; inflated ω area, strongly rounded in shape, ventrally delimited by a shallow depression extending between antennal and hepatic grooves; flat χ area; deep and wide inferior groove.

Pleon and uropods

Somites with a bulge at the basis of the pleurites.

Thoracic appendages

Chelate P1; P1 propodus subrectangular, compressed dorso-ventrally; P1 carpus short, subtriangular.

Ornamentation

Carapace densely covered by rounded tubercles; gastric region with a row of coarse tubercles parallel to the intercalated plate, and with an oblique orbital row ended by a strong antennal spine; pterygostomial region with a row of coarse tubercles under the antennal groove; pleonal tergites with small and widely spaced tubercles; pleonal pleurites densely covered by rounded depressions; P1 propodus and carpus densely covered by small tubercles.

DISCUSSION

Eryma jungostrix is known by only one specimen with a carapace connected to a first cheliped and most of the pleon. A mandible is also preserved ( Fig. 2E ). The generic assignation of this species is supported by the typical carapace groove pattern: short gastro-orbital groove, presence of a junction between postcervical and branchiocardiac grooves, and sinuous hepatic groove.

Eryma jungostrix is the only Eryma species to have a row of tubercles under the antennal groove. Some features of its carapace groove pattern support the distinction of E. jungostrix from other Late Jurassic species.Indeed, the strong inflexion of the cervical groove is not present in E. mandelslohi , E. modestiforme , E. ventrosum , and E. westphali . Moreover, the almost straight postcervical and branchiocardiac grooves are distinct from E. georgeii , E. lerasi , E. mandelslohi , E. modestiforme , E. quadriverrucatum , E. ventrosum , and E. westphali . The carapace ornamentation of E. jungostrix is only made of tubercles contrary to E. georgeii , E. lerasi , E. mandelslohi , E. modestiforme , E. quadriverrucatum , E. ventrosum , and E. westphali .

Figures

FIG. 2. —Eryma georgeii Carter,1868 and Eryma jungostrix Feldmann & Titus,2006 from the Oxfordian:A, B, holotype SM J 3247 of E.georgeii (St Ives,United Kingdom): general view (A), schema (B); C, paratype SM J 3248 of E. georgeii (St Ives,United Kingdom);D, carapace of E.georgeii NMB F501 (Soyhières,Switzerland),left lateral view;E-G, holotype USNM 530027 of E. jungostrix (Utah,United States):left lateral view (E), schema (F), right lateral view (G). Abbreviations:a, branchiocardiac groove; b, antennal groove;b1, hepatic groove;c, postcervical groove;cr, carpus;d, gastro-orbital groove;e1e, cervical groove;i, inferior groove;md, mandible;PoA, post-orbital area; pr, propodus; ω: attachment site of mandibular muscle. Photographs:A, C, D, J. Devillez; E, G, L. O’Reilly.Line drawings: J. Devillez.Scale bars: 1 cm.