Hemigrammus tocantinsi Carvalho, Bertaco & Jerep 2010

Hemigrammus tocantinsi differs from most congeners [except H. bellottii (Steindachner), H. bleheri Géry & Mahnert, H. boesemani Géry, H. brevis Ellis, H. cylindricus Durbin, H. cupreus Durbin, H. erythrozonus Durbin, H. geisleri Zarske & Géry, H. levis Durbin, H. mahnerti Uj & Géry, H. microstomus Durbin, H. mimus Böhlke, H. orthus Durbin, H. rhodostomus Ahl, H. rodwayi Durbin, H. tridens Eigenmann, H. skolioplatus Bertaco & Carvalho, and H. vorderwinkleri Géry] by the number of branched anal-fin rays, 15-17 (vs. less than 15 in H. analis Durbin, H. hyanuary Durbin, H. iota Durbin, and more than 17 on remaining species). From the species with the same range of branched anal-fin rays, Hemigrammus tocantinsi differs by the presence of 1-2 (mode 1) maxillary teeth (vs. 3-11 in H. bellottii, H. cylindricus, H. cupreus, H. mimus, and H. skolioplatus); longitudinal stripe posteriorly broad, larger than one scale depth or than pupil diameter (vs. thinner than one scale depth or pupil diameter or longitudinal stripe absent in H. bellottii, H. boesemani, H. brevis, H. erythrozonus, H. geisleri, H. levis, H. mahnerti, H. microstomus, H. orthus, H. rodwayi, H. tridens, and H. vorderwinkleri); caudal-fin lobes hyaline (vs. presence of a conspicuous broad black marginal or submarginal band across the distal part of caudal-fin lobes in H. bleheri and H. rhodostomus). Furthermore, Hemigrammus tocantinsi can be distinguished from all congeners by the color pattern of live specimens (reddish or orange in male and yellowish pigmented in female).

The species lives in streams, occuring in semi-lentic and lotic shallow areas (up to 1 m deep) with riparian vegetation composed by trees and shrubs. The species was collected syntopically with Aspidoras albater, Astyanax sp., Characidium stigmosum, Corumbataia veadeiros, and Trichomycterus sp. Stomach contents of five specimens were mainly composed by Diptera (pupae) and allochthonous insects, but it was also found authochthonous insects and digested vegetal matter in a lesser amount (Ref. 84464).

Lives in streams, in semi-lentic and lotic shallow areas (up to 1 m deep) with riparian vegetation composed by trees and shrubs. This new species was collected syntopically with Aspidoras albater, Astyanax sp., Characidium stigmosum, Corumbataia veadeiros, and Trichomycterus sp. Five specimens (UFRGS 11300, 25.1-27.1 mm SL) with stomach contents mainly composed by Diptera (pupae) and allochthonous insects, but also found were autochthonous insects and digested vegetal matter in a lesser amount (Ref. 84462).