Tetragonopterus denticulatus Silva, Melo, Oliveira & Benine 2013

Tetragonopterus denticulatus Silva, Melo, Oliveira & Benine, 2013

Fig. 11

Tetragonopterus denticulatus Silva, Melo, Oliveira & Benine, 2013: 1613 –1631 (original description; type locality: “Brazil, Goiás, Aragarças, Rio Araguaia, Amazon basin.

Diagnosis. Tetragonopterus denticulatus is distinguished from all other congeners, except T. anostomus, T. juruena and T. kuluene, by the presence of 5–6 principal teeth on dentary (vs. 4 teeth) and by having thinner and sharper teeth (vs. larger and more robust teeth). It differs from T. anostomus by a terminal mouth (vs. subsuperior mouth); it differs from T. anostomus and T. kuluene by having two conspicuous humeral marks (vs. only one conspicuous humeral mark). Tetragonopterus denticulatus differs from T. anostomus and T. araguaiensis by having 13–14 rakers on the lower limb and 8–9 rakers on the upper limb of the first gill arch (vs. 17–20 and 10–12). Tetragonopterus denticulatus differs from T. juruena and T. kuluene by having 7 scale rows between lateral line and dorsal-fin origin (vs. 6). It further differs from T. argenteus by the presence of eight predorsal scales (vs. 11–17). Tetragonopterus denticulatus differs from T. carvalhoi by the presence of a rounded dark mark on caudal peduncle (vs. a lozenge-shaped mark on caudal peduncle). It differs from T. rarus and T. georgiae by having 3.5 scale rows between lateral line and pelvic-fin origin (vs. 4.5–5.5); it differs from T. rarus by the absence of dark longitudinal stripes on the trunk (vs. presence of stripes). Finally, T. denticulatus differs from T. ommatus by the presence of 3–4 maxillary teeth (vs. 7–8) and by having a mark centered on caudal peduncle (vs. mark limited to the posterior portion of caudal peduncle).

Description. A detailed description of Tetragonopterus denticulatus was recently provided by Silva et al. (2013).

Distribution. Tetragonopterus denticulatus was previously only known from the middle Araguaia basin in central Brazil. During the course of this study, specimens of T. denticulatus were also identified from the Rio Tocantins, extending its distribution range for this river system (Fig. 2 b).

Material examined. Brazil. Types: MZUSP 111002, holotype, 54.8 mm SL, Goiás, Aragarças, Rio Araguaia basin, 15°53’31.5”S 52°15’02”W, C. Oliveira, J. Santana, P. Vênere, & M. Taylor, 23 Jan 2008. LBP 1585, 6 paratypes (1 c&s), 48.5–61.7 mm SL, Mato Grosso, Barra do Garças, Rio Araguaia basin, 15°54’18”S 52°19’24”W, C. Oliveira et al. 13 Dec 2002. LBP 1629, 1 paratype, 58.0 mm SL, Goiás, Aragarças, Rio Araguaia basin, 15°53’35.2”S 52°15’00”W, C. Oliveira et al. 10 Dec 2002. LBP 5751, 5 paratypes, 50.6–59.9 mm SL, same data as holotype. MZUSP 88119, 2 paratypes, 47.4–48.7 mm SL, Goiás, Aragarças, Rio Araguaia basin, 15°53’35.0”S 52°15’08.2”W, V. Garutti & P. Vênere, 0 1 Aug 2005. Non types: MZUSP ex 54091, 2, 65.6–67.1 mm SL, Goiás, Minaçu, Rio Tocantins, Serra da Mesa. NUP 8202, 5, 34.4–53.3 mm SL, Tocantins, Ananás, Rio Araguaia, 6°06’39.2”S 48°17’16”W. UNT 3512, 2, 50.9–67.9 mm SL, Tocantins, Pedro Afonso, Rio Tocantins, 8°58’28”S 48°10’46”W. UNT 3513, 67.9 mm SL; UNT 3519, 1, 59.2 mm SL; UNT 3528, 1, 56.9 mm SL; UNT 3532, 1, 65 mm SL; UNT 3533, 1, 59.8 mm SL; Tocantins, Lajeado, Rio Tocantins, 9°45’2”S 48°21’56”W. UNT 3529, 2, 50.4–50.9 mm SL, Tocantins, Ipueiras, Rio Tocantins basin, 11°18’55”S 48°27’28”W. UNT 3530, 1, 50.2 mm SL, Tocantins, Porto Nacional, Rio Tocantins, 10°43’15”S 48°25’14”W.