Tetranematichthys barthemi Peixoto & Wosiacki 2010

This species is distinguished from T. wallacei and T. quadrifilis by the following: with a serrated margin on the distal portion of the mandibular barbel (vs. presence of conspicuous digitiform elaboration); length of mandibular barbel, 4.5-6.0% HL (vs. 6.3-23.5% in quadrifilis and 7.4-24.6% in wallacei); with a pale ventral region with sparse chromatophores (vs. uniformly brown with darkened spots); a large pale stripe, more evident in females, immediately above the lateral line, extending from the humeral region to the transverse line above the end of the adipose fin (vs. narrow pale stripe in both sexes or absent); presence of irregular patches, which can form a pale distinct stripe in the medial portion of the pelvic fin (vs. uniform dark pigmentation ); no darkened spots on the anal fin in females (vs. presence in both sexes); absence of irregular dark patches along the body (vs. patches present); with 2 pale distinct vertical stripes on the caudal fin in specimens over 160 mm SL (vs. only irregular patches or vertical stripe followed by irregular patches); further differs from T. wallacei by the small size of the snout, 28.8-34.5% HL (vs. 41.2-49.3%) and the width of the body at the insertion of the pectoral fin, 82.1-88.7% HL (vs. 69.2-79.3%); further differs from T. quadrifilis by the reduced size of principal unbranched ray of the upper caudal-fin lobe, 15.6-16.9% SL (vs. 18.1-19.9%), length of head, 24.4-28.2% SL (vs. 28.5-32.3%); width of the body at the insertion of the pectoral fin, 91.6-111.3% HO (vs. 117.0-125.0%) (Ref. 83952).