Three-Dimensional Image Analysis of a Head of the Giant Panda by the Cone-Beam Type CT.

Abstract

ABSTRACT. The cone-beam type CT (Computed Tomography) enabled us to collect the three-dimensional (3D) digitalized data directly from the animal carcass. In this study, we applied the techniques of the cone-beam type CT for a carcass head of the giant panda (Ailuropoda melanoleuca) to obtain the 3D images easily without reconstruction process, and could morphologically examine the sections from the 3D data by means of non-destructive observations. The important results of the study represent the two following points. 1) We could show the morphological relationships between the muscles of mastication and the mandible in non-destructive status from the 3D data. The exact position of the coronoid process could be recognized in the rostro-lateral space of the temporal fossa. 2) By the serial sections from the 3D data sets, the morphological characteristics in the nasal cavity were detailed with high resolution in this rare species. The nasal concha was well-developed in the nasal cavity. The ethmoidal labyrinth was encountered immediately caudal t o the nasal cavity and close to the region of the olfactory bulb. The ethmoidal labyrinth consisted of the complicated osseous struct ure in this area. The data will be useful to discuss the olfactory function in the reproduction behavior of this species.

CRDB: Database of Chemosensory Receptor Gene Families in Vertebrate

“…As pseudogenes can be regarded as relics under the relaxed natural selection, it is possible that some of functional genes have become nonfunctional during the domestication. The giant panda, as a ‘vegetarian carnivore’, contains 1,023 OR genes (648 intact genes and 375 pseudogenes), and indicates that the giant panda still has a strong sense of smell which is concerted with previous findings [31]. Notably, we found that the elephant contains the largest OR gene repertoires (3,824 genes) among vertebrate species, indicating its keener sense of smell than other species.…”