INITIAL PERIOD OF TOOTH DEVELOPMENT IN DOLPHINS (STENELLA-ATTENUATA, CETACEA) - A PILOT-STUDY

Polyodont dentition in dolphins may contain up to 265 simple conical t eeth. In order to analyse prenatal development of this dentition, we c hose the spotted dolphin (Stenella attenuata), where 35 - 37 teeth are present in one jaw quadrant. In this present pilot study, tooth devel opment was studied from 32 to 68 days of ontogenesis (DO) using serial histological sections of embryonic heads. Morphometry and three-dimen sional (3D) computer-assisted reconstruction of dental epithelium were employed. At 32 DO, a thickening of the oral epithelium was apparent in the area of the future dental lamina. On histological sections, thi ckening is considered to be an early morphological sign of odontogenes is. The 3D reconstruction revealed the existence of swellings on the d ental lamina in embryos at 54 DO. During the next period the number of swellings increased. On frontal sections, the epithelium of the swell ings exhibited a tooth-bud shape, described in terrestrial mammals. Ap proximately 24 morphologically similar buds were observed in one jaw q uadrant at 68 DO.