Jonathan W. Armbruster, Leigh A. Tansey & Nathan K. Lujan, 2007, Hypostomus rhantos (Siluriformes: Loricariidae), a new species from southern Venezuela., Zootaxa 1553, pp. 59-68: 59-60

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[[ Hypostomus   ZBK   ]]

The genus Hypostomus   ZBK   has 138 species currently recognized as valid making it the largest genus in the Loricariidae (suckermouth armored catfishes; Armbruster, 2004). Few of the species are well defined, and a comprehensive review of the genus is lacking. Other than individual species descriptions, the taxonomic reviews that have been done on Hypostomus   ZBK   are limited to geographic reviews (Boeseman, 1968; Reis et al., 1990) or to small monophyletic groups such as the H. unicolor   group (Armbruster and Page, 1996; Armbruster, 1998) and the H. cochliodon   ZBK   group (Armbruster, 2003b; Hollanda Carvalho and Weber, 2004).

The type species of Hypostomus   ZBK   is H. plecostomus   , a species from the coastal Guyanas (Boeseman, 1968). It is characterized by dentaries angled just greater than 90° (Armbruster, 2004), viliform teeth, and a generalized morphology consisting of a fairly broad, fairly short body, that is mildly dorsoventrally flattened and brown with dark spots (Boeseman, 1968). There are species of similar morphology in lowlands of most major river basins of tropical South America.

Armbruster (2004) recognized very few subdivisions within Hypostomus   ZBK   , recognizing only an H. emarginatus   ZBK   group and an H. cochliodon   ZBK   group. For the purposes of this paper, Hypostomus   ZBK   is recognized in two main groups the H. emarginatus   ZBK   group (as defined in Armbruster, 2004) and the H. plecostomus   group (all the other species). The H. plecostomus   group additionally has the H. cochliodon   ZBK   subgroup as defined in Armbruster (2003b, 2004), Hollanda Carvalho and Weber (2004), and Armbruster and de Souza (2005). Few species of the H. plecostomus   group (excepting species of the H. cochliodon   ZBK   subgroup) have been described from the Orinoco River basin (just H. argus   ) and none from the Negro (Weber, 2003, pers. obs.). In addition, there is a species of Hypostomus   ZBK   in the Orinoco that is very similar to H. robinii   ZBK   (described from Trinidad, pers. obs.). Some specimens of a Hypostomus   ZBK   with extremely small spots have been found in the Orinoco River drainage of southern Venezuela, and Armbruster (2004) referred these specimens to H. micromaculatus   ZBK   (a species described from Suriname, Boeseman, 1968). Examination of types of H. micromaculatus   ZBK   reveals that the Venezuelan specimens do not belong to this species, and comparison of the specimens to types or original descriptions of all other species of Hypostomus   ZBK   reveals that the specimens represent a new species.