History of commensal rodents on Ishigaki Island (southern Ryukyus) reconstructed from Holocene fossils, including the first reliable fossil record of the house mouse Mus musculus in Japan

摘要: Abstract The history of commensal rodents in mainland Japan and the Ryukyu Islands (Ryukyus) has been poorly understood owing to paucity reliable fossil records. Recent excavation Shiraho-Saonetabaru cave site on Ishigaki Island southern Ryukyus yielded a large number rodent fossils from well-dated sediments ranging Late Pleistocene Holocene. Some were preliminarily assigned Mus musculus Rattus sp. They are described here confirm their taxonomic positions. These forms considered be rodents. A is reconstructed based stratigraphic position relative abundance as well non-commensal native rodent, Niviventer sp., which very abundant most horizons sediments. Before end Pleistocene, no inhabited island, fauna consisted only form. In early Holocene, one forms, M. musculus , invaded but continued form afterward indicates that invasion did not affect fauna. late second invasion, by probably caused rapid decline extinction Since extinction, island comprised forms. Japan, there known occurrences contrast several at Middle Holocene localities. Thus, records first occurrence species important for documenting appearance have appeared much later central Ryukyus.