Paleontological and paleogeographical studies of the first Tertiary small mammal fauna from Japan.

本研究开始时，日本第一个第三纪小型哺乳动物区系（=Dota本地区系）来自岐阜县KaniCity Dota，由2目4科4属组成。本研究新增食虫动物1只、啮齿动物2只、食肉动物2只、偶蹄动物1只；因此，Dota地区动物群现已由5目7科9属组成。分别是：Plesiosorex sp.（食虫目），cf. Amphilagus sp. （Lagomorpha目），Youngofiber sinensis, Anchitheriomys n. sp. ？拟狼蛛属或五虎蛛属，拟狼蛛科等属（啮齿目），熊蛛科等属。，，，，等。（食肉目）和偶蹄目（偶蹄目）。虽然这个新属只在捷克和岐阜地区发现，而且每个地区只有一个标本，但它对研究欧洲和亚洲之间的古生物地理关系非常重要。在6种小型哺乳动物中，有5种在中国与欧洲共有，表明欧洲与亚洲之间存在着广泛的动物交流。在Dota和北美之间共有3个属，说明北美和亚洲之间的动物交换是相当成功的。这些事实表明，中新世早期至中期，欧洲、亚洲和北美之间的动物交换在种类繁多的哺乳动物中更为广泛地发生。多塔地区动物群的组成与捷克的“Merkur-Nord”动物群相似。后者的年龄为欧洲陆生哺乳动物时代的MN3a，约为2200万至2000万年前（MA）。发现多塔当地动物群的中村组并没有发现吻骨类化石，但通常在其上的平木组中发现了吻骨类化石。在欧洲出现于MN4（约18ma）。因此，Dota地区动物群可以与欧洲的MN3相对应。从Nakamura Fm获得的裂变径道年龄。推测Dota地区动物群的年龄约为21 ~ 19 MA，比之前认为的要早一些。少

The first Tertiary small mammal fauna in Japan (=Dota local fauna) from Dota, KaniCity, Gifu Prefecture was composed of 2 orders, 4 families, and 4 genera, when the present study started. Research and excavations by this study added one insectivore, two rodents, two carnivores, and one artiodactyl ; therefore, the Dota local fauna is now composed of 5 orders, 7 families, and 9 genera. They are, Plesiosorex sp. (Insectivora), cf. Amphilagus sp. (Lagomorpha), Youngofiber sinensis, Anchitheriomys n. sp., ? Pseudotheridomys sp. or Pentabuneomys sp., Eomyidae n. gen. et n. sp. (Rodentia), Ursoidea gen. et sp. indet., Musteroidea gen. et sp. indet. (Carnivora), and Traguridae gen. et sp. indet.(Artiodactyla).Although the new genus of Eomyidae is known only from Czech and Gifu Pref. and only by a single specimen from each locality, it is very important in order to study the paleobiogeographic relationship between Europe and Asia.Out of 6 genera of small mammals, 5 genera are common between Do … More ta and Europe, indicating that the faunal interchange between Europe and Asia was extensive. 3 genera are common between Dota and North America, indicating that the faunal interchange between North America and Asia was fairly successful. These facts suggest that faunal interchange among Europe, Asia, and NOrth America during the early to middle Miocene occurred more widely among wide variety of mammals.Dota local fauna is similar to "Merkur-Nord" fauna in Czech in the faunal composition. The age of the latter is MN3a of European land mammal age and is about 22 to 20 million years ago (MA). The Nakamura Formation that yielded the Dota local fauna does not yield proboscidean fossils, but the proboscideans have been commonly known from the overlying Hiramaki Formation. Proboscideans appear in MN4 (ca. 18 MA) in Europe. Thus, the Dota local fauna can be correlated with MN3 in Europe. Fission-track ages obtained from the Nakamura Fm. Suggest that the age of Dota local fauna is about 21 to 19 MA which is somewhat older than previously thought. Less