A comparative SEM-study on the teeth of 10 anuran species.

Teeth of 10 anuran species have been investigated by means of scanning electron microscopy (SEM). Generally a great variability of the structure of dentine crowns and the zone of division was noted not only between the single species, but also within one species on the same dentigerous bone. 4 species (Hyla cinerea, Rana ridibunda, R. hosei, Ptychadena spec.) mostly have more or less bladed bicuspid and clearly divided teeth corresponding to the "Lissamphibia"-pattern. 2 species (Xenopus laevis, X. spec.) exhibit conical spike-like teeth with a trace of a dividing zone similar to those observed in late stage larvae of Urodela. One species (Ceratophrys cranwelli) shows undivided bladed monocuspid teeth. It is assumed that the 2 species of Dendrobatidae (Dendrobates tricolor, D. anthonyi) examined have no zone of division. Its occurrence in Gastrotheca riobambae and in the few juvenile D. tricolor available is still doubtful. Results are discussed regarding the variability of tooth structures (dentine crown, zone of division, pedicel) and the occurrence of 2 types of monocuspid teeth in the Amphibia as well as its possible bearing upon phylogeny and systematics of this group.