1007 Miocene pinniped Allodesmus (Mammalia : Carnivora); with special reference to the "Mito seal" from Ibaraki Prefecture, Central Japan

概要

論文の詳細を見る
Abstract. A partial cranium of a fossil pinniped from late Middle Miocene rocks (ca. 12.0-13.6 Ma) in Mito City, Ibaraki Prefecture, Central Japan, is described as a new species, Allodesmus naorai. The holotype of A. naorai was previously known only by a plaster cast of the "lost specimen" in the collections at the U.S. National Museum of Natural History, but recently the original specimen was rediscovered in the Naora collection at the National Museum of Japanene History. A phylogenetic analysis indicates that A. naorai is the sister taxon of A. packardi, and they form a "broad head" subgroup within the genus. The "broad head" subgroup is placed as the sister group to the A. kernensis-A. sinanoensis species group, which forms a "long head" subgroup within the genus. Allodesmus courseni is the most generalized species among five species known within the genus. These five species and other material referred to the Allodesminae described herein from the western North Pacific indicate that the Allodesminae dominated along the shore of the North Pacific Ocean during the late Middle Miocene and became extinct by the end of the Middle Miocene, probably because of the change to a cooler marine climate.
日本古生物学会の論文
1996-04-30