Orthotheres baoyu, a new species of pea crab (Crustacea: Brachyura: Pinnotheridae) associated with abalones from Tungsha Island, Taiwan; with notes on the genus

The pinnotherid genus Orthotheres Sakai, 1969, is re-diagnosed on the basis of the type species, O. turboe Sakai, 1969, and two allied species, O. haliotidis Geiger & Martin, 1999, and a new species, O. baoyu, from the South China Sea. The genus is characterised by its transversely ovate female carapace with the front visible from dorsal view, a long third maxilliped ischiomerus which is completely fused, the third maxilliped propodus is elongate and extends beyond the articulation with the dactylus, which is inserted subterminally on it, short ambulatory legs, which have a distinctly hooked dactylus, and the dactylus of the second and third legs in which the ventral surface is prominently excavated. The generic affinities of the other species now referred to Orthotheres are also discussed at length. The new species is described, figured and compare with congeners.