MacLarnon, Ann

Rae, Todd

Soligo, Christophe

van Heteren, Anneke H.

lntraspecific variation within the Pleistocene cave bear Ursus spelaeus sensu lato has been discussed extensively. Recently, several subspecies and even species have been proposed based on morphologi­cal and ancient DNA analyses. To test this proposal, the mandibular morphology of U. spelaeus s.l. was analysed using 30 geometric morphometries. Various populations or (sub)species and Alpine localities occupy various places in morphospace, indicating differences and similarities in their morphologies and providing clues to the alpha taxonomy of cave bears. Subsequently, variations in cave bear morphology are interpreted in terms of function. Landmarks for 30 digitisation of the mandible were chosen to reflect functional morphology relating to the Musculus temporalis and M. masseter. Mandibles of U. spelaeus s.l. were digitised with a Microscribe G2. Generalised Procrustes superimposition was performed on the raw coordinates and allometry removed by regressing the Procrustes coordinates onto the natural logarithm of centroid size (LCS). Principal component analyses (PCA) were conducted on the regression residuals, and a Kruskai-Wallis test, analyses of variance (ANOVA) and post-hoc Tukey tests performed on the PC scores. For M. temporalis, PCA differentiates between (sub)species of U. spelaeus s.l. ANOVA indicates that subspecies attribution has a highly significant effect on PCs1 and 2. A post-hoc Tukey HSO test indicates that U. s. deningeroides is significantly different from U. (s.) ingressus on PC 2. PCA also differentiates between localities for U. (s.) ingressus. ANOVA indicates that locality has a highly significant effect on PCs 1 and 2. A post-hoc Tukey HSO test indicates that U. (s.) ingressus from Gamssulzenhohle is highly significantly different from those from Drachenhohle near Mixnitz. The same analyses on M. masseter do not show a difference between subspecies, but show a significant difference between U. (s.) ingressus from Gamssulzenhohle and Merkensteinhohle on PC2. These results suggest that there is a difference in M. temporalis, but not M. masseter, functionality between U. (s.) ingressus and U. s. deningeroides, which may be explained by U. s. deningeroides occupying a temporally and morphologically intermediate position between the other populations of U. spelaeus s.l. and U. deningeri. Additionally, since there are hardly any morphological differences between the proposed (sub)species and significant differences within one (sub)species, (sub)species status of these populations must be reassessed

3D geometric morphometrical analyses of intraspecific variation in the mandible of <i>Ursus spelaeus</i> from the Alpine region

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