Habitat‐associated morphological divergence in two Neotropical fish species

摘要: We examined intraspecific morphological diversification between river channel and lagoon habitats for two Neotropical fish (Bryconops caudomaculatus, Characidae; Biotodoma wavrini, Cichlidae). hypothesized that differences (e.g. flow regime, foraging opportunities) might create selective pressures resulting in divergence conspecific populations. collected from four channel-lagoon habitat pairs the Rio Cinaruco, Venezuela, compared body morphology using geometric morphometrics. There were aspects of both species: (1) placement maximum depth (2) orientation mouth. For species, was positioned more anteriorly (i.e. fusiform) than lagoons. Both species exhibited a relatively terminal mouth lagoons to channel. The B. caudomaculatus upturned, whereas wavrini subterminal, habitats. Observed patterns are consistent with functional principles suggesting adaptive divergence. also show spatial distance habitats, presumably reflecting rates population mixing, appears have constrained diversification. increased Thus apparently reflects balance driven by natural selection, homogenization mixing.