Development of the pattern of dentition and dental laminae of Costa Rican Plethodontid Salamanders (Amphibia : Urodela)

The pattern of development of teeth and dental laminae of three Costa Rican plethodontids (Amphibia, Urodela, Plethodontidae) was investigated using t ransparent preparations, light microscopy and scanning electron microscopy. The teeth of the jaws are monostichously positioned, those of the posterio r vomeral parts are polystichously arranged. The anterior vomeral parts car ry monostichously positioned teeth at the caudal margin; yet, the adult Bol itoglossa subpalmata possesses two lines. As a sex dimorphism adult males d isplay long monocuspid premaxillary teeth which protrude to the outside of the mouth cavity. All species studied possess paired dental laminae in the lower jaw. Nototriton abscondens possesses an unpaired dental lamina in the upper jaw, which is constricted between the unpaired premaxillary and the maxillaries . In contrast, the dental laminae in the upper jaw of B. subpalmata and Oed ipina uniformis are segmented into a premaxillary and two maxillary laminae . All species possess a pair of anterior vomeral and a pair of posterior vo meral dental laminae in the adults, whereas the vomeral dental laminae of t he subadults are unsegmented. The pattern of dentition is compared with tha t of Gyrinophilus and Eurycea.