A new Astyanax tetra has been described from the Iguau River drainage in a recent issue of the journal Neotropical Ichthyology.
Hector Alcaraz, Carla Pavanelli and Vinicius Bertaco name the new species Astyanax jordanensis after the drainage where this species is found (Jordo River, a tributary of the Iguau River).
Astyanax jordanensis belongs to the A. scabripinnis group and can be distinguished from members of the group in having fewer branched anal-fin rays (13"17), more lateral line scales (35"38), a single humeral spot, the teeth on the lower jaw abruptly decreasing in size after the fifth tooth, eye diameter 22.6"29.1% head length, snout length 25.3"29.7% head length, interorbital distance 30.6"35.7% head length, 12"15 predorsal scales, 10"12 dorsal procurrent caudal-fin rays, one or two maxillary teeth, and the presence of a conspicuous midlateral band from the humeral region to the caudal peduncle.
For more information, see the paper: Alacaraz, HSV, CS Pavanelli and VA Bertaco (2009) Astyanax jordanensis (Ostariophysi: Characidae), a new species from the rio Iguacu basin, Parana, Brazil. Neotropical Ichthyology 7, pp. 185"190.