Establishment of Leontocarididae fam. nov. for Leontocaris Stebbing, 1905 (Decapoda: Caridea)

A new caridean shrimp family, Leontocarididae fam. nov., is established to accommodate the deep-water genus Leontocaris Stebbing, 1905, with nine species. The new family can be separated from all other caridean families by the extremely unequal and asymmetrical second pereiopods, with carpus subdivided into four subarticles, the first by far longest, and three much shorter, enlarged, distal subarticles; the chela of the major second pereiopod markedly enlarged, with twisted, lamina-like dactylus and tympanum on mesial face of the palm; the merus of the major second pereiopod with a flange on proximal mesial surface, forming together with the tympanum a chela locking mechanism; the antennal scaphocerite with lateral margin strongly dentate in distal half or third; the uropodal exopod with lateral margin strongly dentate in distal half; and the diagnostic late larval stages (problemacaris larva). Leontocaris is subdivided into three informal species groups based on the combination of several morphological characters.