Redescription of the tadpoles of Epipedobates narinensis and E. boulengeri (Anura: Dendrobatidae).

Abstract

The larval morphology of poison frogs (Dendrobatoidea) has contributed to an understanding of the phylogenetic relationships within the superfamily. Nevertheless, our knowledge of larval morphology is incomplete. The larvae of the dendrobatids, Epipedobates narinensis and E. boulengeri are redescribed, diagnosed, and differentiated from three congeners, as well as sympatric dendrobatoids and closely related genera. Three larval developmental phases are described—viz., (1) back-riding tadpoles, (2) free-swimming tadpoles, and (3) metamorphosing tadpoles. Each larval phase is characterized by ontogenetic changes in external morphology, and there is also morphological variation within each developmental phase. Ontogenetic morphological changes are the most marked in back-riding and metamorphosing phases. The external features of free-swimming tadpoles do not change abruptly, but ontogenetic changes occur in the marginal papillae, stitches of the lateral line system, and tail coloration. Four features that have not been considered previously distinguish species-groups and/or genera—moderate A-2 gap; presence of shelf on back of the upper jaw sheath [UJS]; moderate notch on mid-UJS; and nostril size; these characters are putative synapomorphies of Epipedobates. Metamorphosing tadpoles have some adult features, such as the color pattern on the hind limbs and basal toe webbing, which facilitate identification of species.