Genus Tethysastacus n. gen.

(Fig. 1M)

TYPE SPECIES. — Eryma tithonia Van Straelen, 1936 by monotypy.

DIAGNOSIS. — Fusiform intercalated plate; straight ocular incision; wide post-orbital area; wide and deep cervical groove; no gastroorbital groove; wide postcervical groove, straight, strongly inclined, joined to hepatic groove; concave hepatic groove, joined to cervical groove; dense heterogeneous ornamentation, branchial region with small tubercles and small depression, gastric region with pits, frontal region with strong tubercles and pits.

ETYMOLOGY. — A combination of Tethys, the vast Mesozoic ocean, and the Latin astacus (“marine crayfish” or “escrevisse” in Old French).

DISCUSSION

Tethysastacus n. gen. is assigned to the Erymidae based on the presence of the intercalated plate. It differs from all other genera of erymid lobsters by its extremely simple carapace groove pattern and the absence of branchiocardiac and gastroorbital grooves. The postcervical groove is straight, whereas it is inflected in all other genera.