Microglanis

Horácio Mori & Oscar Akio Shibatta, 2006, A new species of Microglanis Eigenmann, 1912 (Siluriformes, Pseudopimelodidae) from rio São Francisco basin, Brazil., Zootaxa 1302, pp. 31-42 : 32

[[ 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 río 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 Maquiné basin, RS), M. cottoides (Boulenger, 1891) (rio Camaquã basin, RS), M. parahybae (Steindachner, 1880) (rio Paraíba 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 São 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 São 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.