Evaluating the consistency and taxonomic importance of cheliped and other morphological characters that potentially allow identification of species of the genus Perisesarma De Man, 1895 (Brachyura, Sesarmidae)

Abstract

Recent studies suggest that the family Sesarmidae represents a monophyletic taxon, but within-family taxonomy and phylogenetic relationships need to be resolved. One of the most speciose and taxonomically complex genera of this family isPerisesarma. Only a few characters allow to discriminate between species of this genus. Among them, the number and shape of male dactylar tubercles and number of teeth of the pectinated crests are the main diagnostic features. A review of these key characters indicates some intraspecific variability which sometimes renders identification difficult. The present study shows that male dactylar tubercles and pectinated crests are in principle good diagnostic characters at species level in the genusPerisesarma, but in several cases show some overlap among species, due to intraspecific variability. New morphological characters should be considered, but in this study we show that the morphology of gonopods and the gastric mill are not informative enough for identification.