Morphological variation in the crayfish Cambarellus (cambarellus) montezumae (decapoda: cambaridae)

The morphological variation exhibited by populations of Cambarellus (Cambarellus) montezumae in central and western Mexico is analyzed using somatic and genitalic characters. Five populations (Tequisquiapan, Queretaro; Chapultepec and Xochimilco, DF; Atlangatepec Darn, Tlaxcala; and Aljojuca Crater Lake, Puebla) were analyzed through seven morphological (shape and position of the caudal process, mesial processes, and central projection of the gonopod, shape and position of the annulus ventralis and postannular sclerite) and nine morphometric variables (total and cephalothorax length, areola length and width, rostrum length, chela length and height, palm length and movable finger or dactyl length). The results show that both morphological and morphometric characters can be useful to distinguish among populations and that there are two new species within this species complex.