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This species is distinguished from its congeners by the following characters: the color pattern is composed of dark longitudinal stripes along the trunk and many spots scattered on the dorsum and flanks; similar color patterns also found in some individuals of I. apteryx (Xingu basin), I. australis (Laguna dos Patos and Uruguay basins), I. boticario (Tocantins basin), I. cahyensis (Cahy basin), and I. parahybae (Paraíba do Sul and nearby Atlantic coastal rivers). It differs from these five species by the following features: from apteryx, cahyensis, parahybae by the pelvic fin usually i,4 (vs. absent or i,3), the pectoral fin usually i,5-6 (vs. i,3-4), and the absence of the anterior cranial fontanel (vs. presence); from australis by the absence of the anterior cranial fontanel and pores i1 and i3 of the infraorbital canal (vs. presence); from the hypogean boticario by the pectoral fin with usually i,5-6 rays (vs. i,7-8) and the absence of pore s2 of the supraorbital canal and pores i1 and i3 of the infraorbital canal (vs. pores s2, i1, and i3 present) (Ref. 117615). |