A new species of Chaetostoma Tschudi (Siluriformes: Loricariidae) from Colombia with a definition of the C. anale species group

Abstract

Chaetostoma formosae sp. nov. is described from piedmont tributaries of the upper río Meta on the Cordillera Oriental in Colombia. The new species is distinguished from its congeners by the presence of an elongate unbranched anal-fin ray with two posterior dermal ridges in mature males, the presence of strongly recurved cheek odontodes, the presence of a parieto-supraoccipital dermal keel, the posterior margin of the pelvic-fin strongly projected and angulate in shape in mature males, and by details of coloration. The new species belongs to an informal monophyletic group herein called the Chaetostoma anale species group, along with two additional species, C. anale and C. jegui, from Colombia and Brazil respectively, based on an apomorphic modification of the anal fin in mature males.