MINOR DENTAL TRAITS IN EAST-AFRICAN CAPE HARES AND SAVANNA HARES (LEPUS-CAPENSIS AND LEPUS-VICTORIAE) - A STUDY OF INTRASPECIFIC AND INTERSPECIFIC VARIABILITY

Occlusal variants of a total of 6252 teeth of 246 specimens of cape ha res and 42 specimens of savanna hares were studied. Most hares were co llected in the Great Rift Valley (Kenya) during 1967-1968. Some savann a hares were obtained from the Queen Elizabeth National Park (now Ruen zori NP, Uganda) in the same period. In total 61 variants concerning e namel folds, plication, and lakes were described. Only three teeth (I- 2, M(3), I-1) proved invariant in both species. In each species, three regional units (sampling locations) were specified. Quantitative anal yses of nomnetric (epigenetic) variability and geographic divergence b etween the regional units and between the two species were based on 31 dichotomized (0/1 scores) characters. They were created from the comm only encountered variants. A high degree of bilateral symmetry was rev ealed in most characters, but characters varied independently from one another. This indicated a lack of complex morphotypes in the occlusal patterns. The frequencies of all character states were calculated for all regional units and the combined species samples. No categorical d ifferences were found in occlusal characters between the two species. The interindividual epigenetic variability was calculated as the mean of standard deviations of single characters in each sample based on th e character scores. It did not differ between the two species and amon g the regional units within each species. Only in savanna hares from t he Queen Elizabeth Park was the tendency of folding and plication of e namel structures somewhat reduced. Divergence of occlusal character st ates between the two species and among regional units was assessed by using C. A. B. Smith's 'mean measure of divergence' as a distance meas urement. Thirteen of 15 pairwise morphological distances differed sign ificantly from zero. A UFGMA dendrogram based on these distance measur ements revealed distinct epigenetic separation of the two species. Wit hin each species, slight geographic divergence corresponded to the spa tial distribution of the regional units. In cape hares, spatial diverg ence also paralleled some changes in climatic conditions. In view of t he lack of complex occlusal types and the larger interspecific diverge nce as compared to the intraspecific, character variation is likely to be caused by phylogenetic rather than by ecogenetic processes.