Tetragonopterus rarus (Zarske, Géry & Isbrücker 2004)

This species is distinguished from its congeners by the having longitudinal dark stripes on the lateral surface of the body (vs. absent); differs from all congeners, except T. georgiae, by the number of longitudinal scale rows between lateral line and pelvic-fin origin 4.5-5.5 (vs. 3.5); differs from T. anostomus, T. denticulatus, T. juruena, T. kuluene by the number of principal dentary teeth 4 (vs. 5-6) and by the relatively robust teeth on dentary (vs. sharper teeth); differs from T. anostomus, T. araguaiensis by the number of gill-rakers on the lower limb of the first gill arch 12-13 (vs. 16-20); differs from T. carvalhoi by the shape of the dark mark on the caudal peduncle which is round (vs. lozengular); differs further from T. ommatus by having teeth on the maxilla 2-4 (vs. 7-8) and the dark mark centered on caudal peduncle (vs. mark limited to the posterior portion of caudal peduncle); differs from T. anostomus by the terminal mouth (vs. subsuperior) and from T. anostomus, T. kuluene by the humeral marks 2 (vs. 1); differs from T. argenteus by the predorsal scales 8 (vs. 11-17) and from T. denticulatus by having humeral marks separated by 1 vertical scale row (vs. 3) (Ref. 124043).

Dorsal soft rays (total): 9; Analsoft rays: 28 - 33; Vertebrae: 30