Procambarus (Ortmannicus) hidalgoensis (Crustacea:Decapoda:Cambaridae), a new species of crayfish from Mexico

A new species of crayfish from Camino a Olotla, Tlanchinol County, Hidalgo, Mexico, is described. Procambarus (Ortmannicus) hidalgoensis is most closely related to P. (O.) cuevachicae (Hobbs, 1941) and P. (O.) toltecae Hobbs, 1943, from which it can be distinguished by having a gonopod with a mesial process slightly flattened distally and directed caudo-distally; a cephalic process slightly larger than the rest of the terminal elements, originating on the caudal surface; and a plate-like caudal process, exhibiting a strongly folded external part of the pleopod. The annulus ventralis in the new species is rhomboidal, with two strong crests, forming a deep V-shaped depression anteriorly, ending in a sinus in the middle region.