Tethysastacus tithonius (Van Straelen, 1936) n. comb.

(Fig. 10 A-D)

Eryma tithonia Van Straelen, 1936: 8-9, pl. 2, fig. 1-2. — Roger 1946: 42. — Secrétan 1964: 68. — Förster 1966: 123. — Feldmann & Titus 2006: 64.

Eryma tithonium – Schweitzer et al. 2010: 25.

TYPE MATERIAL. — Holotype MNHN.F. J03351.

TYPE LOCALITY. — Laciterne-Boisset near Moulès-et-Baucels, Hérault department, Languedoc-Roussillon region, South France.

TYPE AGE. — Valanginian, Early Cretaceous.

DESCRIPTION

Subrectangular carapace in lateral view (holotype: CL = 21 mm; CH = 10 mm); long, toothless rostrum; intercalated plate present; short, oblique ridge near rostrum basis; straight ocular incision; wide tuberculate post-orbital area; wide, deep cervical groove, probably joined to dorsal margin, joined to antennal groove; antennal groove shallower than cervical groove, reaching post-orbital area; gastro-orbital groove absent; straight, oblique postcervical groove, as wide and deep as cervical groove, joined to hepatic groove; slightly concave hepatic groove, narrower than cervical and postcervical grooves, joined to cervical groove; curved inferior groove, joined to ventral margin behind its junction to hepatic groove, as wide and deep as hepatic groove; branchial, cardiac and hepatic regions with small tubercles intercalated with deep circular pits; similar ornamentation in pterygostomial region but with smaller and shallower pits; cephalic region with heterogeneous ornamentation: gastric region with circular pits, frontal region with strong tubercles and small pits; dense ornamentation on the whole carapace.

COMMENTS

The holotype presents a carapace in butterfly-like position with a strong dorsoventral flattening along the dorsal midline (Fig. 10A). This mode of preservation is characteristic of a lobster molt (Glaessner 1969; Charbonnier et al. 2012b). A pronounced rupture of the dorsal midline is observed with a strong rotation of the two halves of carapace. This suggest a probable hinge-type opening during the ecdysis (Charbonnier et al. 2012b).