New occurences for Gnathodolus bidens and Synaptolaemus cingulatus and descriptions of two new species of Sartor (Characiformes, Anostomidae)

Abstract

Gnathodolus MYERS, 1927, Synaptolaemus MYERS & FERNANDEZ YEPEZ in MYERS, 1950 and Sartor MYERS & CARVALHO, 1959 are genera of the family Anostomidae which have hitherto been considered to be monotypic and to have geographical distribution restricted to the Orinoco River (Gnathodolus), the Xingu (Sartor) or both (Synaptolaemus). The species of the se genera are characterized by the entirely superior mouth and the symphyseal pair of teeth on the lower jaw much larger than the remainder. As a result of taxonomic surveys of specimens from various rivers in the Brasilian Amazon, we are now able to widen the known distribution of these genera in the Amazon region and to conclude that Sartor, rather than being monotipic, includes three species, two of which are here described as new: Sartor elongatus n. sp. from the Trombetas River and S. tucuruiense n. sp. from the Tocantins River, both in the state of Pará, on the left and right banks of the Amazon River, respectively. The two new species differ from Sartor respectus in the presence of 16 rather than 12 circumpeduncular scales and from each other in the more elongated form of S. elongatus