Adaptation in the skulls and cranial muscles of South American characinoid fish

The skulls and cranial muscles of the primitive characins Creatochanes and Brycon are described. Other Characinoidei, which have been selected to illustrate the remarkable adaptive radiation of the suborder, are compared with them in detail. They are: Myleus , a deep-bodied herbivore specialized for biting pieces from plants; Serrasalmus , the piranha, a predator which bites pieces of flesh from large prey; Pyrrhulina , a surface feeder; Leporinus , a herbivore with jaws and teeth suited for nibbling rather than biting; Hoplias , a long-jawed predator; and Anisitsia , a detritus feeder which is convergent with the grey mullets.