Rathbun, 1924
Rostral spines slender, cylindrical, with a single accessory spine; intercalated spine absent, orbit comprising only eave and postorbital lobe; carapace widened posteriorly, width at least two thirds postrostral carapace length, branchial region 1.5 times as wide as hepatic region; preorbital spine large, acute; large species (carapace length more than 50 mm). (Davie 1996)
Type species: Pisa serpulifera Guérin-Méneville, 1829, by designation of Rathbun, 1924.
Species treated:
Paranaxia serpulifera (Guérin-Méneville, 1829)