Ontogenetic color changes may strengthen suggestion about systematic affinities between two species of Chironius (Serpentes, Colubridae)

Abstract

genus Chironius include 20 species that dwell mainly in rainforests of Central and South America (Dixon et al. 1993). These medium to large snakes are diurnal, arboreal to terrestrial, and feed upon frogs (Dixon et al. 1993, Sazima and Haddad 1992, Marques et al. 2001). Several species are arboreal and their ground color are green (e.g. Campbell and Lamar 1989, Dixon et al. 1993, Marques et al. 2001). Their morphology also reflect their arboreal habits as these snakes have large eyes, slender bodies, and long tails (Dixon et al. 1993, Marques 1998). Ontogenetic color changes are common within the genus, juveniles sometimes differing markedly from adults (Dixon et al. 1993, Marques et al. 2001). Chironius flavolineatus is regarded as the only species with no ontogenetic color changes (Dixon et al. 1993), but a close examination of preserved juvenile specimens revealed faint cross-bands in some of them (OAVM, pers. obs.). Upon examining preserved specimens Dixon et al. (1993) note that only C. laevicollis and C. scurrulus juveniles have Ontogenetic color changes may strengthen suggestion about systematic affinities between two species of Chironius (Serpentes, Colubridae)