Four new crayfishes (Decapoda: Cambaridae) of the genus Orconectes from Texas

Abstract

Four new crayfishes of the genus Orconectes from Texas are described, including Orconectes (Hespericambarus) cyanodigitus, Orconectes (Gremicambarus) castaneus, Orconectes (Buannulifictus) occidentalis and Orconectes (B.) texanus. O. cyanodigitus, of the Red River system, is most closely aligned with O. deanae and O. difficilis. It is distinguished from the former by its gonopod's much shorter, less recurved central projection; and from the latter by its much longer mesial process. O. castaneus, of a small section of the Colorado River system, is most similar to O. nais and O. palmeri longimanus. Its obliterated areola, longer gonopod processes, annulus ventralis structure and color distinguish it from the former; while its shorter gonopod processes, annulus ventralis structure, and color pattern distinguish it from the latter. O. p. longimanus, heretofore considered widely ranging in Texas, is split into three closely allied taxa, with its Texas range reduced to the Red River system and a small tributary of Trinity River; O. texanus occupying most of the remainder of east Texas, including the Sabine, Neches, Trinity, San Jacinto and Navasota basins; and O. occidentalis occupying the Colorado, Guadalupe, Medina, Frio and Nueces systems of central Texas. O. texanus is distinguished from O. p. longimanus by its gonopod's more recurved processes and more strongly tapered central projection, annulus ventralis structure and color pattern; and from O. occidentalis by its annulus ventralis configuration and color pattern. O. occidentalis is distinguished from O. p. longimanus primarily by its annulus ventralis structure and color pattern. Evidence of the extirpation of O. p. longimanus from its type locality is presented.