Key to the species of Chaetostoma from the Orinoco River Basin in Colombia

Photographs illustrating the characters of interest in the present key are available along with dorsal, lateral and ventral overall views for each of the species found in the Colombian Orinoco drainage, as well as additional materials are available at https://github.com/gaballench/Cjoropo.

1a. Cheek odontodes straight; parieto-supraoccipital excrescence absent............................................ 2

1b. Cheek odontodes curved, parieto-supraoccipital excrescence present............................................ 3

2a. Snout covered with plates; light spots present on head................................... Chaetostoma platyrhynchus

2b. Snout naked; light spots sometimes present on head, body, pectoral and pelvic fins, dorsal fin always with light spots........................................................................................... Chaetostoma dorsale

3a. Spots present only on head and area surrounding dorsal-fin base; dorsal, pectoral, pelvic and anal fins with dark bands; sexual dimorphism in the anal fin where males have the second unbranched anal-fin ray elongated........ Chaetostoma formosae

3b. Spots present on head and body; dorsal, pectoral, pelvic and anal fins with spots, sexual dimorphism in the anal fin absent................................................................................... Chaetostoma joropo n. sp.