Dentition of the upper and lower jaws and the palate of three larvae of different sizes (29 mm, 47 mm, 53 mm long) and one adult specimen of the paedomorphic Cryptobranchus alleganiensis is described. The 29 mm larvae had ossifi ed, but not fully developed premaxillae and vomeres, partly ossifi ed incomplete palatines, dentaries and still developing coronoids. Teeth were present only on the premaxillae, dentaries and vomeres, but were still not ankylosed to the bones; they were monocuspid and non-pedicellate. However, in the 47 mm larva teeth on all dentigerous bones were bicuspid and pedicellate as typical for urodele teeth after metamorphosis. Thus, paedomorphosis infl uences dentition already in a relatively early time in ontogeny in C. alleganiensis. Such heterochronous effects on dentition obviously occur in different degrees within paedomorphic Urodela and deserve closer attention. Presently, however, knowledge of them is still fragmentary. With the exception of the palatines and the coronoids, which were toothless, praemaxillae, vomeres and dentaries bore a single row of established teeth. Course and number of dental laminae was consistent with the conditions found in other Urodela (a continuous dental lamina in the upper jaw arcade; a discontinuous in the lower jaw arcade and two vomerine dental laminae). However, in contrast to other Urodela we found no signs of dental laminae accompanying the coronoids and the palatines, which explains the total absence of teeth on these bones.

Paedomorphosis, dentition, bicuspidity, heterochrony, Cryptobranchus alleganiensis.