アホウドリ属の最古の記録,Diomedea tanakai sp. nov. : 日本の中新統から産出したアホウドリ

概要

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Tertiary fossil albatrosses (Family Diomedeidae) are only known from a handful of specimens from America, Australia, Antarctica, Britain, Japan and France. They first appear in the late Eocene of Seymour Island, Antarctica, achieving a Pacific and Atlantic Ocean distribution by the Pliocene. Two tarsometatarsi were collected from an late-Early Miocene horizon at Yanaidani, Aki County, Mie Prefecture, Japan. These specimens represent the first definite fossil evidence for the family Diomedeidae in the North West Pacific and the oldest occurrence of the genus Diomedea in the fossil record. These tarsometatarsi of this new species possess some unique osteological characters and, in terms of size, are significantly smaller than those of extinct and extant species. The presence of the Diomedeidae in the fossil avifauna of the North West Pacific further enhances the knowledge of the evolutionary history of this family and seems to suggest that the Albatrosses were derived from a small, near-shore Procellariiform ancestor which adapted (some time in the Oligocene or early Miocene) to an oceanic lifestyle.
国立科学博物館の論文