Fishes from the Río Alvarado drainage, Upper Río Magdalena Basin, Colombia Author Albornoz-Garzón, Juan G. Author Conde-Saldaña, Cristhian C. Author López-Delgado, Edwin O. Author García-Melo, Jorge E. Author Villa-Navarro, Francisco A. text Check List 2020 2020-09-18 16 5 1181 1198 http://dx.doi.org/10.15560/16.5.1181 journal article 10.15560/16.5.1181 1809-127X Chaetostoma thomsoni Regan, 1904 Figure 3J Material examined. COLOMBIA • 66, 23.0– 69.2 mm SL ; Quebrada La Caima ; 04°35′45.8″N , 074°56′39.6″W ; 374 m a.s.l. ; 19 Sep. 2012 ; Cristhian C . Conde-Saldaña , Juan G . Albornoz-Garzón leg.; CZUT-IC 10121 . • 14, 25.5–97.1 mm SL ; Río Alvarado-Chucuní ; 04°27′56.7″N , 075°03′46.7″W ; 697 m a.s.l. ; 19 Sep. 2012 ; Juan G . Albor- noz-Garzón, Cristhian C . Conde-Saldaña leg.; CZUT-IC 10219 . Identification. Distal portion of snout without plates. Interoperculum with four to five odontodes. Caudal pedun- cle with five rows of plates. Anal fin rays I , 5. Caudal fin emarginated with lower portion longer than upper portion. Light spots usually concentrated on head. Fins with white to yellow bands. Distal margin along caudal fin pale, more evident at tips ( Regan 1904 ).