1 0 0 0 OA 北海道,忠類産ナウマンゾウの再検討
The Churui specimen was found in 1969 and 1970 from Bansei, Churui, Makubetus-cho, Nakagawa-gun, Hokkaido, and is one of the most important whole skeletons of Palaeoloxodon naumanni. Herein, we reexamine the molar number and specific identification of this specimen. As a result of our observations, four molars that were previously identified as second molars of one individual are re-identified as third molars of one individual. These molars correspond to the group 25-27 of Laws (1966), and are therefore assumed to represent an age of about 50 years. Observations of the epiphyseal fusion of the postcranial bones in the Churui specimen support the result that the animal used its third molars. A molar that was previously identified as a third molar from the same individual as the four "second molars" of P. naummmni, is re-identified as a second or third molar of the woolly mammoth Mammuthus primigenius, as determined by morphological characters. It gave a radiocarbon date of 42,850+510BP. Woolly mammoths inhabited Hokkaido from 45ka to 16ka, while the horizon of P. naumanni from Churui is estimated to be 120ka. This suggests that the molar of the woolly mammoth fell from the upper part of the cliff at the excavation site of the Churui specimen, instead of being recovered from the excavation plane.