Reexamination of Fossil Shrews (Sorex spp.) from the Middle Pleistocene of Honshu Island, Japan

概要

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Taxonomic status of fossil Sorex shrew specimens from the late Middle Pleistocene of Honshu Island was addressed. Multivariate analyses of upper and lower jaws were conducted for the fossil specimens as well as for 8 species of Recent Sorex shrews from Japan and adjacent regions. It was confirmed that S. shinto and S. hosonoi already inhabited Honshu Island in the late Middle Pleistocene. Most fossil specimens previously referred to S. minutissimus and S. gracillimus in Honshu should be regarded as S. hosonoi, although some specimens could not be completely distinguished from S. gracillimus. Thus, the appearance of S. hosonoi ascends, at least, to the late Middle Pleistocene during which time they were more broadly distributed, including northern Honshu, than at present (only in central Honshu). Most middle size fossils should be regarded as S. shinto, but at least one specimen was identified as S. caecutiens. It was also demonstrated that other species of Sorex shrews larger than S. shinto and S. hosonoi were present during the Middle Pleistocene of Japan. Most of the large fossils were considered to be S. isodon, which had not been recorded from and is now absent in the Japanese Islands. In addition, there was one specimen of another large species, S. unguiculatus, in Honshu during the Middle Pleistocene, which now is absent in Honshu.
Mammalogical Society of Japanの論文
2010-09-01