Arthropoda (Phylum) > Crustacea (Subphylum) > Malacostraca (Class) > Eumalacostraca (Subclass) > Eucarida (Superorder) > Decapoda (Order) > Pleocyemata (Suborder) > Brachyura (Infraorder) > Eubrachyura (Section) > Heterotremata (Subsection) > Portunoidea (Superfamily) > Portunidae (Family) > Thalamitinae (Subfamily) > Thalamita (Genus)

Spiny Rock Crab

Carapace with 3 pairs of gastric ridges, epibranchial ridge interrupted by cervical groove and medially, otherwise perfectly smooth; front typically with 6 lobes, sometimes number reduced by fusion of medians and submedians; 5 antero-lateral teeth decreasing slightly in size from front to rear. Basal antennal joint with a low ridge bearing spare and rounded granules or tubercles. Upper surface of cheliped palm usually with 1 spine and a proximal tubercle on outer 2 spines on inner side; inner face of left limb only with a broad anterior eminence, otherwise smooth. Posterior border of propodus of swimming leg with about 5 spines and 4-6 small, inconspicuous tubercles. Male first pleopod long and thin, gradually tapering to tip; inner surface with an indistinct double row of subterminal bristles; outer surface without ornamentation. (Türkay 1995)

Front 6-lobed (sometimes 4-lobed), median frontal lobes much broader than laterals; 5 antero-lateral teeth; first antero-lateral tooth entire; fourth antero-lateral tooth large, same size as fifth; ridge on basal antennal joint with granules; inner surface of hand of cheliped smooth. (Davie 1999)

Synonym
Thalamita prymna crenata (Latreille, 1829)