Caracterização morfológica dos representantes do gênero Ituglanis (Siluriformes, Trichomycteridae) da bacia Amazônica brasileira

Abstract

This project aimed to contribute for a better taxonomic understanding of the species of the genus Ituglanis, Trichomycteridae (Siluriformes) occurring in the Brazilian Amazon. The genus occurs in all the large drainages in South America. However, only two species were registered to occur in Central Amazon, Ituglanis amazonicus and I. parkoi, both described based in only one specimen. In this thesis, these species are redescribed based on a larger number of specimens of I. amazonicus, providing information on morphological variation, and on the holotype and X-ray images for I. parkoi. As the major results, four new morphotypes were determined for the Brazilian Amazon herein proposed as new species and the geographic distribution of the genus was widened for several drainages in the Amazon . Ituglanis sp. n. ‘tapajos’ presented a color pattern of difuse blotches; autopalatine with a slight concavity on its mesial margin; pelvic-fin rays not covering anus and urogenital opening; 43- 45 vertebrae and frontal fontanel absent. Ituglanis sp. n. ‘dardanelos’ presented 4-5 pairs of pleural ribs; 38-40 vertebrae; color pattern with dense cromatophore irradiation sometimes forming longitudinal lines on the dorsum and frontal fontanel absent. Ituglanis sp. n. ‘xingu’ is characterized by a color pattern of big and coalescing blotches densely covering the dorsum, blotches also on ventral surface and supraoccipital fontanel rectangular. Ituglanis sp. n. ‘morena’ is characterized by presenting three pores on lateral line (II1, II2 and II3); many vertebrae (51) and anus and urogenital papillae located closer to anal-fin base than to tip of pelvic–fin rays.