A phenetic analysis of the genus Colostethus (Anura: Dendrobatidae)

Abstract

The principal goal of the study was to provide a phenetic review of the genus Colostethus, one of three genera in the family Dendrobatidae. The results of the phenetic study are used to·examine biological relationships in the genus. The genus Colostethus was selected for this study because the genus was relatively well defined, yet it had never been studied as a group; tadpoles are carried by the adults during part of their life cycle, enabling positive larval identification; and, individuals are relatively easy to collect. Furthermore, the various species· in the genus are found in diverse habitats ranging from lowland tropical rainforest to paramó, from undisturbed natural habitats to man-made habitats such as pastures, irrigation ditches, and cultivated areas. The genus is restricted to the neotropics where it occurs from southeastern Brazil throughout the Amazon Basin, the Andes of Peru, Ecuador and Colombia, along ·the north coast of Venezuela, on Trinidad and Tobago, and through lower Central America to central Costa Rica. Specimens have been collected from sea level (in the. inter-tidal zone) to over 4000 m. The phenetic study was accomplished in six phases: 1) recording of individual character states; 2) pooling data from individuals by locality; 3) clustering populations using correlation and taxonomic distance phenograms; 4) delimiting species clusters; 5) pooling data from individuals by species; 6) clustering species using correlation and distance phenograms. The species phenogram is then used heuristically to determine if the species clusters reflect meaningful biological patterns that can be tested.