Genus Oxyropsis Eigenmann, Eigenmann, 1889

Oxyropsis Eigenmann, Eigenmann, 1889: 39 .

Type-species: Oxyropsis wrightiana Eigenmann, Eigenmann, 1889 . Type by original designation. Gender feminine.

Included species. Oxyropsis acutirostra Miranda-Ribeiro, 1951; Oxyropsis carinatum (Steindachner, 1879); and Oxyropsis wrightiana Eigenmann, Eigenmann, 1889 .

Diagnosis. Oxyropsis is diagnosed as monophyletic based on three non-exclusive synapomorphies: width of exposed area of nuchal plate equal to its length (char. 35.1); 28 or more vertebrae (char. 41.0); and height of neural and haemal spines of caudal vertebra smaller than its width (char. 43.1).

Comparisons. The species of Oxyropsis are further distinguished from other hypoptopomatins by having only one single row of aligned odontodes along the trunk midline lying adjacent and immediately dorsal to the lateral line canal (vs. odontodes not in a single row). Oxyropsis is distinguished from other hypoptopomatins, except Acestridium and Niobichthys, by the caudal peduncle strongly depressed, elongated and narrow (vs. caudal peduncle not depressed). Additionally, the species of Oxyropsis can be further distinguished from Hypoptopoma by the width of the exposed area of the nuchal plate, which is equal to its length, resulting in a typically small, roundish and not laterally expanded nuchal plate (vs. nuchal plate laterally expanded); and by the possession of only three plates in the mid-dorsal series (vs. four plates).