Ituglanis macunaima, new species, is described from the rio Araguaia basin, Mato Grosso, Brazil. It is distinguished from its congeners by the following combination of characters: posterior fontanel absent; pectoral-fin rays usually i,4; pelvic-fin rays usually i,4; branched caudal-fin rays usually 5,5; mottled color pattern formed by irregular to roundish dark brown spots on whitish background; reduced supraorbital canal with pores s1 and s2 lacking; reduced infraorbital canal with pores i1 and i3 lacking; 2-3 pleural ribs; and 35-38 vertebrae. A detailed description and illustrations of the skeleton of I. macunaima are also provided. Comparisons with other trichomycterids are presented, and several reductive traits of I. macunaima are discussed. Some comments are made about the systematics and phylogeny of the genus.
Loricarioidea; Osteology; Paedomorphosis; Taxonomy; Systematics
