Middle and Late Pleistocene Wild Boar Remains from Locality 1 of Ube Kosan Quarry in Yamaguchi Prefecture and from the Kannondo Cave Site in Hiroshima Prefecture, Western Japan.

Abstract

A systematic description is given to a Middle Pleistocene remain (M3) from Locality 1 of Ube Kosan Quarry, and three Late Pleistocene remains (frontal bone, I2 and P4) from the Kannondo cave site. These remains are important to elucidate morphological characters of wild boars inhabited the mainland of Japan during the Pleistocene, because wild boar remains dated certainly as the Pleistocene are quite limited in Japan. The remains are compared with the living and Quaternary fossil suid species known from East Asia. The morphological characters of the remains are mostly coincident with those of Sus scrofa, an extant species now widely distributed in Eurasia, but the exact identification is left pending owing to the insufficiency of the morphological data of the fossil species as well as the poor preservation of the present remains. The remains are therefore assigned to S. cf. scrofa. As regards the size of the remains, the M3 is larger than that of S. scrofa leucomystax, an extant subspecies of S. scrofa now distributed in Honshu-Shikoku-Kyushu, but is approximately as large as those of S. scrofa from other Middle Pleistocene localities. The other three remains are approximately as large as S. s. leucomystax. On the basis of the present study as well as the data so far obtained, it is inferred that the wild boar of S. scrofa or its allied form already inhabited Honshu-Shikoku-Kyushu in the middle Middle Pleistocene, and then decreased toward the Late Pleistocene. From the late Late Pleistocene to Holocene, it increased drastically, and became a dominant artiodactyl in the Holocene fauna of Honshu-Shikoku-Kyushu.