Distinguished from all other species of Australoheros (except A. facetus) by having prognathous mouth (vs. isognathous); from species of the A. facetus, A. forquilha, A. kaaygua and A. scitulus species groups, and from A. acaroides, A. ykeregua, A. angiru and A. taura by having 12 caudal vertebrae (vs. 13 - 15) and 14 precaudal vertebrae (vs. 12 - 13); from species of the A. facetus, A. forquilha and A. kaaygua species groups by having three abdominal bars in all stages of life (vs. always four abdominal bars in juveniles, and adults with three bars in about 50% and four in about 50% of all specimens examined); from A. perdi by having 26 total vertebrae (vs. 25); from A. ykeregua by the absence of dark marks on the suborbital region (vs. presence); from A. agiru by having a conspicuous rounded caudal-fin base spot (vs. spot very narrow or absent); from all its congeners of the A. autrani species group (except A. mattosi and A. montanus) by having a fewer body depth (39.0 - 42.2% SL in A. tavaresi vs. 45.7 - 50.9% SL in A. autrani, 44.6 - 49.0% SL in A. barbosae, 47.3 - 51.2% SL in A. ipatinguensis, 46.6 - 49.8% SL in A. macacuensis, 44.0 - 48.2% SL in A. macaensis, 43.8 - 50.1% SL in A. muriae, 42.6 - 46.1% SL in A. paraibae, 47.4 - 51.3% SL in A. ribeirae, 43.7 - 46.0% SL in A. robustus, 44.0 - 48.2% SL in A. saquarema, 42.6 - 50.3% SL in A. capixaba); from A. saquarema, A. muriae, A. robustus, A. barbosae, A. macacuensis, A. ipatinguensis, A. paraibae and A. ribeirae by having a longer caudal peduncle (caudal peduncle length 9.8 - 11.6% SL in A. tavaresi vs. 6,6 - 8,0% SL in A. ipatinguensis, 6.7 - 9.0% SL in A. saquarema, 5.1 - 7.9% SL in A. macacuensis, 5.5 - 8.7% SL in A. barbosae, 7.1 - 8.9% SL in A. muriae, 6.4 - 8.1% SL in A. paraibae, 7.4 - 9.2% SL in A. robustus and 6.6 - 9.1% SL in A. ribeirae); from A. barbosae, A. macacuensis, A. paraibae, A. ribeirae and A. saquarema by having a fewer preorbital depth (51.2 - 60.0 % SL in A. tavaresi vs. 60.5 - 65.3% SL in A. barbosae, 62.2 - 65.4% SL in A. macacuensis, 60.4 - 65.2% SL in A. paraibae, 64.2 - 73.3% SL in A. ribeirae, 66.0 - 69.1% SL in A. saquarema); from A. macacuensis and A. montanus sp. n. by having arms of trunk bar 7 with the same width (vs. posterior arm of trunk bar 7 wider than anterior one); from A. mattosi by having anal-fin base squamation beginning at the sixth anal-fin spine (vs. anal-fin base squamation beginning at the third anal-fin spine); and from A. ribeirae by having a fewer head depth (head depth 80.6 - 94.2% HL vs. 95.4 - 98.9% HL) (Ref. 89866).