Astyanax

Bertaco, Vinicius A. & de Lucena, Carlos A. S., 2010, Redescription of Astyanax obscurus (Hensel, 1870) and A. laticeps (Cope, 1894) (Teleostei: Characidae): two valid freshwater species originally described from rivers of Southern Brazil, Neotropical Ichthyology 8 (1), pp. 7-20 : 19

Key for the species of Astyanax from laguna dos Patos system

1. Anterior humeral spot distinctively oval-shape ................. 2

1’. Anterior humeral spot vertically elongate or other form but never oval-shape ................................................................... 3

2. Humeral spot trespassed by a diffuse vertical bar followed posteriorly by a second bar of same intensity, and without a narrow anteroventral downward extension surpassing the lateral line; body short and high (body depth 35.0- 50.0% SL); branched anal-fin rays 22-28; absence of maxillary teeth; all fins green-yellow pigmented in life .............................................................. Astyanax jacuhiensis

2’. Humeral spot not trespassed by vertical bar and posterior bar absent, with a narrow anteroventral downward extension surpassing the lateral line; body elongate (body depth 30.7-39.0% of SL); branched anal-fin rays 15-23; maxilla with 1-3 teeth; all fins red-orange pigmented in life .................................................................... Astyanax laticeps

3. Presence of two humeral spots, the second diffuse .......... 4

3’. Presence of only one humeral spot .................................... 7

4. Head moderately sharp; branched anal-fin rays 22-27; larger orbital diameter (42.4-50.7% of HL); 2-5 (usually 3-4) maxillary teeth; dentary teeth slender and spaced ..................................................................... Astyanax henseli

4’. Head robust; branched anal-fin rays 12-21 (rarely 22 or 23); smaller orbital diameter (24.8-37.7% of HL); up to 3 (usually 1-2) maxillary teeth; dentary teeth thick .............. 5

5. First humeral spot with the dorsal portion wider and ventral portion narrow, not forming a wedge, and extending over 4 to 5 horizontal series of scales ............... Astyanax obscurus

5’. First humeral spot with the dorsal portion slightly wider than ventral portion, forming a uniform wedge, and extending over 5 to 6 horizontal series of scales ............... 6

6. Branched anal-fin rays 13-15 (rarely 12 or 16, usually 13-14); smallorbitaldiameter(24.8-34.8%ofHL); largecaudalpeduncle depth (12.2-15.3% of SL) ............ Astyanax brachypterygium

6’. Branched anal-fin rays 15-17 (rarely 14 or 18, usually 16-17); large orbital diameter (28.1-37.7% of HL); small caudal peduncle depth (10.4-14.2% of SL) ... Astyanax cremnobates

7. Humeral spot extending over the series of scales above and below the lateral line, forming a uniform wedge, and extending over 5 to 6 horizontal series of scales; lateral line scales 34-36; branched anal-fin rays 21-24 ................................................... Astyanax eigenmanniorum

7’. Humeral spot located only above of the lateral line scales, not forming a wedge, and extending over 2 to 3 horizontal series of scales; lateral line scales 38-41; branched anal-fin rays 25-30 ............................... Astyanax sp. aff. fasciatus (sensu Melo & Buckup, 2006)