The shape of the teeth and their sex-dependent dimorphic expression in thre
e species of Costa Rican plethodontids (Bolitoglossa subpalmata, Oedipina u
niformis and Nototriton abscondens) were studied using light microscopy and
scanning electron microscopy.
The teeth of the vomerine tooth patches are about one third larger than the
teeth of the jaws in B. subpalmata and O. uniformis, whereas all teeth of
N. abscondens are of about uniform size. The occurrence of bicuspid tooth g
erms in the fetus proves that primary teeth are bicuspid in these directly
developing plethodontids. Females possess only bicuspid teeth consisting of
a pedicel and a crown, as is considered characteristic for urodeles after
metamorphosis. Adult males possess conical monocuspid teeth on the premaxil
lary. These teeth - which are similar to the typical late larval tooth of s
alamanders presenting a larval stage - are about twice as big as the neighb
ouring bicuspid maxillary teeth. N. abscondens males possess some monocuspi
d teeth and teeth of aberrant shapes on the premaxillary and the maxillarie
s. A tendency to build more monocuspid teeth in the premaxillary region tha
n in the maxillary region can be observed in this species.
We suppose that different degrees of sensitivity to androgens in each secti
on of the dental lamina of the upper jaw cause the secondary occurrence of
conical monocuspid teeth predominantly on the premaxillary section.