Population analysis of dental anomalies of ottersLutra lutra from eastern Germany

A sample of 1037 skulls of ottersLutra lutra (Linnaeus, 1758) from eastern Germany was analysed for inherent dental abnormalities. Deviations from the normal dental pattern were found in 107 individuals. A total of 150 cases were classified in 5 categories of abnormality. In considering variations from the normal number of teeth, supernumerary (polydonty, 1.7%) was more frequent than missing teeth (oligodonty, 0.9%). In most cases, numerical variations were not connected with phylogenetic background. The most frequent variations were displacement of teeth in the tooth row (6.0%) and deviations of the normal shape of teeth (3.3%). Variations of the local position of teeth occurred in 2.6% of cases. None of these deviations showed significant sex-dependent differences. Furthermore, no regional differences in the frequencies of these anomalies were noticed. Another 459 otters (822 cases) had accessory roots at P2, P3, or P4. These characters were considered as non-metrical traits and used to study epigenetic regional differentiation. The Mean Measure of Divergence segregated the Baltic coast from almost all other regions. Preliminary results of analysis of Fluctuating Asymmetry are presented, using these traits to demonstrate the utility of dental deviations for estimating influences on developmental stability. Generally, it can be stated that the dentition of otters is very stable.