冠状縫合を使った鮮新統-更新統産の三尖の角を持つシカ類の分類について

抄録

The coronal sutures of nine specimens representing eight species of Japanese three pointed deer from the Pliocene-Pleistocene were investigated. Patterns of the coronal sutures are clearly observed in six specimens representing five species: Cervus praenipponicus from Kawasaki and Ichihara, C. akiyoshiensis from Mine, C. kazusensis from Otsu, C. shimabarensis from Minamishimabara and an unidentified specimen from Taga. It is advantageous to paleontology that the coronal sutural patterns are observable even in fragmentary fossil specimens. Combined with morphology of antlers, it is useful for classification of three pointed deers. The sutures of C. praenipponicus, C. kazusensis and C. shimabarensis are "W"- shape or open pentagonal shape expanding to the rostrad. In contrast, the suture of the Taga specimen exhibits a "V" -shape curve. Therefore, at least two groups are discriminated in Pliocene-Pleistocene three pointed deer species inhabited Japanese Islands. The "W" -shape suture is well observed in the extant Cervinae C. unicolor, C. nippon and C. elaphus, while the "V" -shaped type is seen in C. timorensis, C. eldi, Axis porcinus, Dama dama and Elaphurus davidianus. The Japanese three pointed deer species having the "W" -shaped sutures are closely related to C. unicolor. On the other hand, the Taga specimen having a "V" -shaped suture is supported the relation to C. timorensis or A. porcinus. It conflicts with the general arguments on Cervinae that A. porcinus is not closely related to C. unicolor or C. timorensis. The Taga specimen needs further reaserch utilizing other skeletons from the same locality to determine its taxonomic position.