Geographical variation on Roeboexodon geryi (Myers) (Ostariophysi: Characiformes: Characidae)

Abstract

Populations of Roeboexodon geryi from Suriname, French Guiana, rio Xingu, rio Tapajós, and rio Tocantins in the Amazon region obtained from zoological collections were studied in order to verify the existence of undescribed species in the genus. However, although the results showed trends on differentiation between Surinam/French Guiana vs. Amazon basin relative to number of scales on lateral line, these were not diagnostic. The results of a Free-Size Canonical Variate Analysis also revealed trends on formation of distinct morphological groups, but did not revealed diagnosable populations which could be putative species. These local differences are therefore interpreted as geographical variations of a single species of the monotypic genus Roeboexodon.