Diversification in the Mexican cyprinid fish Algansea monticola (Pisces: Cyprinidae), with description of a new subspecies

" Algansea monticola archidion is described from the Río Huaynamota of the Río Grande de Santiago basin of western México. It differs most trenchantly from A. m. monticola from the Río Juchipila in having a mode of eight dorsal rays, greater interorbital distance and longer pectoral fins. The two subspecies coexist in the Bolaños basin which lies between and has apparently captured tributaries to both the Ríos Huaynamota and Juchipila. Male morphometric variation reflects this presumed historical pattern of stream capture but comparable female variation does not. Possible reasons for this difference are discussed "