A new species of Microglanis Eigenmann, 1912 (Siluriformes, Pseudopimelodidae) from rio São Francisco basin, Brazil.
Author
Horácio Mori
Author
Oscar Akio Shibatta
text
Zootaxa
2006
1302
31
42
http://www.zoobank.org/urn:lsid:zoobank.org:pub:D25EBB8D-1F2D-41DB-989F-34EDC6FC0572
journal article
z01302p031
[[
Microglanis
Eigenmann ]]
The genus
Microglanis
was proposed by Eigenmann (1912) to include
Microglanis poecilus
and related species of reduced size, reaching a total length of nearly 110 mm (Eigenmann, 1912). This genus is further characterized by the wide mouth (gape same of the head width), short barbels (occasionally reaching pectoral-fin origin), small eyes without free orbital margin, absence of axillary pore, a dark saddle straddling supraoccipital area to the end of dorsal-fin base, pre-maxillary dental plate with rounded margin and thin mesocoracoid arch (Shibatta, 2003a; 2003b).
Fourteen species are valid in the genus, occurring from trans-Andean drainages in Peru and Ecuador, eastward to the Orinoco and Amazon basins and southward to the
rio
de la Plata basin, Argentina (Bertaco & Cardoso, 2005; Shibatta & Benine, 2005).
Microglanis
is also present in the eastern coastal rivers of Brazil, with the following species:
M. cibelae Malabarba & Mahler-Jr., 1998
(rio
Maquine
basin, RS),
M. cottoides (Boulenger, 1891)
(rio
Camaqua
basin, RS),
M. parahybae (Steindachner, 1880)
(rio
Paraiba
do Sul basin, RJ) and
M. nigripinnis Bizerril & Perez-Neto, 1992
(rio Macacu basin, RJ) (Bizerril & Perez-Neto, 1992; Malabarba & Mahler-Jr., 1998; Shibatta, 2003a).
Samples of
Microglanis
were recently collected in the rio
Sao
Francisco basin. This is an independent hydrographic basin and has an area of 634 km2 (Cunha, 1998), across the Brazilian States of Minas Gerais, Bahia, Pernambuco, Sergipe and Alagoas. The peculiar geomorphologic aspects and the occurrence of endemic species (e.g.,
Conorhynchus conirostris (Valenciennes, 1840)
,
Duopalatinus emarginatus (Valenciennes, 1840)
,
Franciscodoras marmoratus (Reinhardt, 1874)
,
Lophiosilurus alexandri Steindachner, 1876
, among others), suggest an old isolation of the rio
Sao
Francisco system. Examination of specimens of
Microglanis
from this basin reveals that they constitute a new species, with a set of distinctive morphological characters. This new species is described herein.