On the strategies of the skull from in various squirrels in Southeast Asia

点击翻译按钮获取中文摘要

We examined the skulls of Nihon squirrel, northern Siberian squirrel, Finlayson's squirrel, gray-bellied squirrel, red-cheeked squirrel, and black giant squirrel. We used the skull of the Museum specimens for statistical analysis.The orbit and the brain case were examined to analyze the morphological characters. The data was compared to discuss the relationships between the shape and function. We collected the data of the angle of the Foramen magnum and the frontal bone parts, indices of the orbit volume, the size zygomatic arch. The visual sense was statistically discussed to quantitatively analyze the adaptation pattern of the eye. We could clarify the morphological evolution, such as elongation of the spalanchnocranium, change of shape of the nasal bone, the angle of the nose in various adaptation pattern. We could quantitatively indicate the morphological strategies determined from the adaptation pattern in each species.In the statistical analysis, we analyzed the raw data and the … More proportion indices, and undertook the ANCOVA to reject the size factors. In the Sciuridae including many species of different body size factor. We could visualize the adaptation strategies from the principal component and canonical discriminant analyses in the two-dimensional coordinates. To discuss the phylogeny in the groups, we also made the Q-mode matrices to undertake the cluster analysis. In the red-cheeked squirrel, gray-bellied squirrel, black giant squirrel, giant flying squirrel, and lesser flying squirrel.We could clarify the relationships between the functional adaptation pattern and the morphological similarities of the skulls to detail the geographical variations of the squirrels. We could demonstrate that the Finlayson's squirrel, Formosa squirrel, red-cheeked squirrel, black giant squirrel and giant flying squirrel showed the differences of the adaptation pattern in a single species. It enabled us to detail the functional adaptation in mastication related to the zoogeographical evolutionary factors. Less