Hypostomus rhantos (Siluriformes: Loricariidae), a new species from southern Venezuela.
Author
Jonathan W. Armbruster
Author
Leigh A. Tansey
Author
Nathan K. Lujan
text
Zootaxa
2007
1553
59
68
http://www.zoobank.org/urn:lsid:zoobank.org:pub:F87041AF-3B5A-4F02-9D98-886814090969
journal article
z01553p059
F87041AF-3B5A-4F02-9D98-886814090969
[[
Hypostomus
]]
The genus
Hypostomus
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
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
group (Armbruster, 2003b; Hollanda Carvalho and Weber, 2004).
The type species of
Hypostomus
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
, recognizing only an
H. emarginatus
group and an
H. cochliodon
group. For the purposes of this paper,
Hypostomus
is recognized in two main groups the
H. emarginatus
group (as defined in Armbruster, 2004) and the
H. plecostomus
group (all the other species). The
H. plecostomus
group additionally has the
H. cochliodon
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
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
in the Orinoco that is very similar to
H. robinii
(described from Trinidad, pers. obs.). Some specimens of a
Hypostomus
with extremely small spots have been found in the Orinoco River drainage of southern Venezuela, and Armbruster (2004) referred these specimens to
H. micromaculatus
(a species described from Suriname, Boeseman, 1968). Examination of types of
H. micromaculatus
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
reveals that the specimens represent a new species.