Sarcoglanidinae

Wilson J. E. M. Costa, Sergio M. Q. Lima & Carlos Roberto S. F. Bizerril, 2004, Microcambeva ribeirae sp. n. (Teleostei: Siluriformes: Trichomycteridae): a new sarcoglanidine catfish from the Rio Ribeira do Iguape basin, southeastern Brazil., Zootaxa 563, pp. 1-10 : 2

[[ Subfamily Sarcoglanidinae ]]

The Sarcoglanidinae (family Trichomycteridae) constitutes one of the most intriguing South American catfish assemblages. This group is known from a few specimens, which are classified at present into six genera and seven species (Costa, 1994; de Pinna, 1998; de Pinna & Winemiller, 2000). The scarcity of available specimens may be due to their very small size (usually less than 25 mm SL as adult), and their apparent preference for difficult to sample sandy banks of rivers and streams (Costa and Bockmann, 1994; Costa, 1994). Most sarcoglanidines are considered miniaturized fishes (Weitzman and Vari, 1988; Costa and Le Bail, 1999) and all except for one species are poorly pigmented, with translucent body in life. Two taxa, Sarcoglanis simplex Myers & Weitzman and Malacoglanis gelatinosus Myers & Weitzman possess an uncommon deep body, hypertrophied saclike adipose organ above pectoral fin, and absence of premaxillary teeth (Myers and Weitzman, 1966), and three taxa, S. simplex , M. gelatinosus , and Stauroglanis gouldingi de Pinna , have few or no opercular and interopercular odontodes (Myers and Weitzman, 1966; de Pinna, 1989; Costa, 1994). The three pairs of barbels found in other trichomycterids (maxillary, rictal and nasal barbels) are also present in sarcoglanidines, although nasal barbels are often shortened. In addition, some sarcoglanidine taxa have a pair of a barbel-like structures on the ventral surface of the head (Myers and Weitzman, 1966; Costa and Bockmann, 1994). All species of five genera, Sarcoglanis Myers & Weitzman , Malacoglanis Myers & Weitzman , Stauroglanis de Pinna , Stenolicmus de Pinna & Starnes , and Ammoglanis Costa are endemic to the Amazon. In contrast, the other taxon, Microcambeva barbata Costa & Bockmann , is endemic to a small coastal basin of southeastern Brazil, the Rio São João drainage, in the Brazilian Atlantic forest area (Costa & Bockmann, 1994). The present paper reports the description of a new species of Microcambeva , the largest sarcoglanidine fish, known from the rio Ribeira do Iguape basin, southeastern Brazil, which is about 500 km, in a straight line, from the type locality of M. barbata .