It is native to South America, where it occurs in the Caquetá River basin in Colombia.

[1] In 2004, Jonathan W. Armbruster of Auburn University reclassified the species as a member of Chaetostoma,[2] although FishBase and ITIS both refer to it as Cordylancistrus platyrhynchus, and neither source lists either of Armbruster's names (Chaetostoma platyrhynchus and C. platyrhyncha) for the species as a synonym.

[3][4] In his 2004 reclassification, Armbruster used platyrhyncha and platyrhynchus interchangeably when referring to the species.

Armbruster and Milton Tan referred to the species as C. platyrhyncha in their 2012 description of Cordylancistrus santarosensis (which has subsequently been reclassified as Transancistrus santarosensis),[6] furthering the confusion surrounding the correct spelling of the name.

In 2016, Gustavo A. Ballen of the University of London and Alexander Urbano-Bonilla and Javier A. Maldonado-Ocampo of the Pontifical Xavierian University ruled that changing the specific epithet to platyrhyncha or platyrhynchum to comply with the ICZN's name gender guidelines was not in this case justified and that the species should be referred to as Chaetostoma platyrhynchus.