Trochilocharax ornatus gen. et spec. nov. – a new, small (up to 17.0 mm SL) characid fish from Peru is described. Presumably it has an internal insemination. The new genus and species is characterized by a naked, scaleless body. Only the sexually ripe males have a puoch scale like the members of the subfamilies Glandulocaudinae and Stevardiinae. The females and sexually immature specimens of both sexes have no scales. The puoch scale covers a convexity (a gland?), what indicates to an internal insemination. Further features are: D ii 7; A iv 22 – 24, seven (fourth to tenth) anal-fin rays with one relatively large hook in the anterior part of the fin; all other fins without hooks; maxilla long and narrow, with fi ve to eight conical teeth on the anterior part of the bone; praemaxilla and anterior part of lower jaw with irregularly distributed conical teeth, partly protruding out of the mouth. 34 – 35 (4 + 8 + 22 – 23) vertebrae. There is a remarkable sexual dimorphism and sexual dichromatism. The phylogenetical position of the genus is unknown. It belongs to the Stevardiinae but not to the Xenurobryconini, because there is no synapomorphy of the Xenurobryconini developed. For this reason a new tribus – Trochilocharacini trib. nov. – is created for the new genus Trochilocharax.

Teleostei, Characiformes, Characidae, Trochilocharax, new species, Trochilocharacini, Peru, South America, Biogeography