Key to the Venezuelan species of Geophagus

1 Infraorbital stripe complete (Fig. 1), extending from ventral edge of orbit to edge of preopercule or dorsal half of interopercule ................................................................. 2

­ Infraorbital stripe absent, or reduced to a dark mark on preopercule (Fig. 1) .............. 3

2 Dorsal fin base with sheath of scales; faint horizontal stripes on flank G. taeniopareius

­ Dorsal fin base without sheath of scales; no horizontal markings on flank ................... ........................................................................................................... G. grammepareius

3 Base of gill filaments on first gill arch largely covered by broad flap of skin; no discernible lateral bars on preserved specimens (Fig. 2 e); Cuyuní river drainage ............. ........................................................................................................... G. brachybranchus

­ Base of gill filaments on first gill arch narrowly covered with skin at base; 4 to 7 lateral bars on preserved specimens; Orinoco or Río Negro drainages .......................... 4

4 Seven dark bars on flank, with bars 4 and 5 forming a “ Y ” pattern; ventral margin of caudal peduncle contained 1.1 to 1.3 times in dorsal margin of caudal peduncle; subopercule caudoventrally naked (Fig. 2 a).................................................... G. dicrozoster

­ Fewer than seven bars on flank; ventral margin of caudal peduncle contained 1.5 to 1.6 times in dorsal margin of caudal peduncle; subopercule fully scaled ......................... 5

5 Dorsal lobe of caudal fin with accessory lateral line extension between rays D3 and D4; preopercular mark present; four, broad and parallel, caudo­ventrally inclined lateral bars on flank (Fig. 2 c) ....................................................................... G. winemilleri

­ Dorsal lobe of caudal fin without accessory lateral line extension; preopercular mark absent; six, vertical and parallel bars on flank (Fig. 2 b) ................................ G. abalios