Palaeontologia Sinica (Whole Number 198, New Series C, Number 30)Neogene Rodents from Central Nei Mongol, China,The Neogene was a time of modernization in the evolution of mammals, the formation of the modern mammal pattern of composition at higher taxonomic ranks. Protrogomorph rodents continued an earlier trend of declining, and sciuromorph and myomorph rodents began a great diversification during this time interval. In the Neogene, mammals differentiated into distinct distributions in North and South China. The northern faunas reflect a temperate, relatively arid steppe environment, similar to the present Palearctic Region, while the faunas in the south indicate a tropical or subtropical forest environment with characteistics of the Oriental Region. Remains of Neogene mammals in China are mostly recovered from the north, mainly in the Mongolian-Xinjiang highland and its adjacent areas. Fossil rodents found in this region contain 87 genera (10 new)and 168 species (53 new), belonging at least to 15 families (Appendix 1), and accounting to 67.4% genera and 69.4% species of the animal diversity known in the Neogene deposits of equivalent ages in northern China. Among them, 36 genera are congeneric to European representatives. This again testifies that central Nei Mongol is an important region in biostratigraphic and biochronologic study, because of tese rich Neogene assemblages with their highly diverse and abundant fossil materials.
All the specimens described are housed in the Instirute of Vertebrate Paleontology and Paleoanthropology, Beijing "IVPP V xxxx" is a catalogue number of specimens in theinstitute. Detailed specimens for each taxon described are given in the Chinese text. "IMxxxx" or "DB xxxx" represent the number of fossil locaties
I. Introduction
II. Fossil Localities and Geologic Setting
III. Systematic Description
1. Rodentia Bowdich, 1821
(1)Distylomyidae Wang, 1988
(2) Tachyoryctoididae Schaub, 1958
(3) Aplodontoidea Brandt, 1855
(4) Aplodontidae Brandt, 1855
(5) Mylagaulidae Cope, 1881
(6) Sciuridae Fischer von Waldheim, 1817
(7) Pteromyinae Brandt, 1855
(8) Gliridae Thomas, 1897
(9) Eomyidae Deperet et Douxami, 1902
(10) Castoridae Hemprich, 1820
(11) Dipodoidea Fischer von Waldheim, 1817
(12) Zapodidae Coues, 1875
(13) Dipodidae Fischer von Waldheim, 1817
(14) Cricetidae Fischer von Waldheim, 1817
(15) Gerbillidae De Kay, 1842
(16) Arvicolidae Gray, 1821
(17) Myospalacidae Lilljeborg, 1866
(18) Muridae Gray, 1821
IV. Fauna Succession and comparisons
V. Origin and Evolutionary history
VI. Mammal Chronology and Stratigraphy
VII. Biogeographic Relationships and Paleoecologic Characters