Moenkhausia

Bertaco, Vinicius A., Jerep, Fernando C. & Carvalho, Fernando R., 2011, A new characid fish, Moenkhausia aurantia (Ostariophysi: Characiformes: Characidae), from the upper rio Tocantins basin in Central Brazil, Zootaxa 2934, pp. 29-38 : 37

Key to the species of Moenkhausia described from Tocantins-Araguaia basin

1 Branched anal-fin rays 17 to 19.......................................................................... 2

- Branched anal-fin rays 21 to 30.......................................................................... 3

2 Lateral line scales 27 or 28; one maxillary tooth; presence of a dark blotch on caudal-fin base; black triangular humeral spot......................................................................................... M. pyrophthalma

- Lateral line scales 36 or 37; four to five maxillary tooth; absence of a dark blotch on caudal-fin base; humeral spot diffuse.............................................................................................. M. dasalmas

3 Dark spot on upper caudal-fin lobe....................................................................... 4

- Absence of dark spot on upper caudal-fin lobe............................................................... 5

4 Lateral line scales 29 to 35; a large and irregularly shaped humeral spot located above the fifth to ninth perforated scale of lateral line............................................................................... M. hysterosticta

- Lateral line scales 36 to 38; a vertically elongate humeral spot located just after upper margin of opercle......... M. loweae

5 Two humeral spots; 7 or 8 scales above and 6 or 7 scales below the lateral line; 37 to 41 lateral line scales.. M. pankilopteryx

- One humeral spot; 5 to 6 scales above and 3 or 4 scales below the lateral line; 33 to 37 lateral line scales............... 6

6 Branched anal-fin rays 21 to 25; predorsal scales 7 or 8; presence of a dark saddle-like mark anterior to the dorsal-fin origin; lateral line scales 35 to 37.................................................................. M. tergimacula

- Branched anal-fin rays 26 to 30; predorsal scales 10 to 12; absence of dark spot anterior to dorsal-fin origin; lateral line scales 33 to 35......................................................................... M. aurantia , new species