F I G U R E 1 in Comparative larval ontogeny of two fish species (Characiformes and Siluriformes) endemic to the S ao Francisco River in Brazil

F I G U R E 1 Photomicrographs of longitudinal sections of larval (a), (c), (e) Prochilodus argenteus and (b), (d), (f) Lophiosilurus alexandri: a, (b) 0 days post hatch (dph) showing mouth () closed in (a) and open in (b), with yolk sac (YS), nervous system (NS), primitive digestive tube (); (c), (d) 4 and 10 dph, respectively, showing vestige of yolk sac (), swim bladder (SB), hepatopancreas (HP) and intestine (); (e), (f) 7 dph showing oropharyngeal cavity (OC), oesophagus (), stomach (ST), intestine (INT) and swim bladder (SB)