Key to species of Hoplias

1. Medial margins of contralateral dentaries abruptly converging toward mandibular symphysis, forming a Vshaped margin in ventral view (Fig. 1d); dorsal surface of basihyal and basibranchials with tooth-bearing plates (i. e. rough tongue) ............................ Hoplias malabaricus group

1’. Medial margins of contralateral dentaries almost parallel to each other, resulting in a U-shaped margin in ventral view (Figs. 1 a-c); dorsal surface of basihyal and basibranchials without tooth-bearing plates (i. e. smooth tongue) ................................................................................... 2

2. Dark oval spot on opercular membrane present; accessory ectopterygoid absent .................................... Hoplias aimara

2’. Dark oval spot on opercular membrane absent; accessory ectopterygoid present ............... 3 ( Hoplias lacerdae group)

3. Specimens larger than 60 mm SL with 4 well-defined patches of several small pores of laterosensory system along the ventral surface of dentary, specimens smaller than 60 mm SL only with four pores (Figs. 1 a-c); lateral line scales 34- 39 [36] ............................................... Hoplias curupira n. sp.

3’. Specimens of any size always with 4-8 relatively large pores of laterosensory system along the ventral surface of dentary; lateral line scales 38-48 .......................................... 4

4. Laterosensory system along ventral surface of dentary with 6-8 [7] pores; lateral line scales 43-48 [46] .................................................................... Hoplias lacerdae

4’. Laterosensory system along ventral surface of dentary with 4-6 pores; lateral line scales 38-46 .............................. 5

5. Anterior profile of head rounded in lateral view; laterosensory system along ventral surface of dentary always with 5 pores; ground coloration of head and body dark brown or dark grey ................. Hoplias australis n. sp.

5’. Anterior profile of head angular in lateral view; laterosensory system along ventral surface of dentary with 4-6 pores; ground coloration of head and body dark to light brown ............................................................................ 6

6. Lateral line scales 38-43 [41] ................... Hoplias brasiliensis

6’. Lateral line scales 42-46 [44] ............... Hoplias intermedius