Key to trans-Andean Pimelodus

1a. Adipose fin length contained less than 4.35 times in SL.......................................................2

1b. Adipose fin length contained more than 4.35 times in SL......................................................3

2a. Head length contained more than 3.85 times in SL, predorsal distance contained more than 2.63 times in SL, body with dark spots, 23–29 total gill rakers in the first branchial arch........ Pimelodus grosskopfii (Magdalena River Basin of Colombia)

2b. Head length contained less than 3.77 times in SL, predorsal distance contained less than 2.63 times in SL, body plain, bluegrey coloration on the sides and dorsal region, spots absent, 20–24 total gill rakers in the first branchial arch............................................................. Pimelodus crypticus n. sp. (upper Cauca River Basin of Colombia)

3a. Interorbital width contained more than 2.78 times in HL, body with dark spots.....................................4

3b. Interorbital width contained less than 2.78 times in HL, body light brownish, spots and bands absent, ventral region white...................................................................................... Pimelodus yuma n. sp. (middle and lower Cauca River Drainage, Magdalena River Drainage, and Sinú River Basin of Colombia)

4a. Head length contained less than 3.7 times in SL, pectoral fin I,9, 28–37 gill rakers in the first branchial arch...................................................... Pimelodus coprophagus (Lake Maracaibo Basin of Venezuela and Colombia)

4b. Head length contained more than 3.7 times in SL, pectoral fin I,9-11, 24–28 gill rakers in the first branchial arch.........5

5a. Small dark spots on flanks and head, pectoral fin I,9-10................................................................ Pimelodus punctatus (Atrato and Baudó River Basins of Colombia and Tuyra and Chagres River Basins of Panamá)

5b. Body and head with dark spots also present on dorsal, pectoral and adipose fins, pectoral fin I,10-11............................................................... Pimelodus navarroi (Lake Maracaibo Basin of Venezuela and Colombia).