Rhamdia reddelli, new species, the first blind pimelodid catfish from Middle America, with a key to the Mexican species

A new blind, depigmented catfish is described and illustrated from Cueva del Nacimiento del Rio San Antonio, Oaxaca, Mexico, and compared with its closest relative.Rhamdia laticauda.It resembles that species in having strong, retrorse serrae on the pectoral spine, and a shallowly notched caudal fin, but differs in the longer head, longer adipose fin, larger cephalic sensory pores, and longer and more numerous gill rakers (1 1-16 vs. 9-12).The karyotype (2n = 58) of the new species and a key to described Mexican species are given.A list of nominal and misidentified Mexican species is presented and R. laticauda.R. parryi.and R. guatcmalensis are illustrated.