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.