Biodiversity of Small Mammals and Paleoenvironment of Transbaikalia and North Mongolia in the Late Pliocene

This paper reports the results of analysis on small mammal faunas dwelling during the Late Pliocene the Transbaikal and Northern Mongolia regions. They were found to share many common species, even though some differences linked with local and regional specifics of the environment are the case. High diversity of small mammal taxa, species richness and their prominent quantity specify the localities of Udunga, Beregovaya and Tologoi in Transbaikal region and in Shamar of Northern Mongolia. The compositions of all faunas point to the existence of the savanna-like landscapes and warm semiarid climate in that period

Determining the ontogenetic variation of lower cheek teeth occlusal surface patterns in lagomorphs using micro ct-technology

Altres ajuts: SYNTHESYS Project http://www.synthesys.info/, financed by European Community Research Infrastructure Action under the FP6 "Structuring the European Research Area" (AT-TAF-3508)Micro CT-scanning has been performed on the lower jaws of some selected lagomorph taxa in order to reconstruct unequivocally their controversial ontogenetic development. The analyses were concentrated on the development of p3, and on the sequences of lobe connections and on the sequence of appearance/disappearance of flexids/fossettes of p4-m2. This is the first time that this approach has been applied to lagomorphs and opens promising perspectives especially for the taxonomy and phylogeny of this complex order

Occurrences of Sinolagomys (Lagomorpha) from the Valley of Lakes (Mongolia)

The genus Sinolagomys is an early representative of the Family Ochotonidae, appearing first in the late early Oligocene of Central Asia. It is known in China from Shargaltein Tal, Taben Buluk, Ulan Tatal and northern Junggaria, and a few specimens from Tatal Gol, Mongolia have been published. For most occurrences the genus is not represented by many specimens. Extensive studies in the Valley of Lakes, Central Mongolia, have produced a large number of sinolagomyin fossils spanning at least ten million years, and belonging to five species: Sinolagomys kansuensis, S. major, S. gracilis, S. ulungurensis and S. badamae sp. nov. Descriptions of these are given, as well as definition of the new species. Sinolagomyins flourished during the late Oligocene and early Miocene and came to occupy vast territories from China through Mongolia and Kazakhstan. The evolution of this ochotonid group is characterized by increasing taxonomic diversity and progressive development of rootless cheek teeth.Other Research Uni

Oligocene and early Miocene mammal biostratigraphy of the Valley of Lakes in Mongolia

The Taatsiin Gol Basin in Mongolia is a key area for understanding the evolution and dispersal of Central Asian mammal faunas during the Oligocene and early Miocene. After two decades of intense fieldwork, the area is extraordinarily well sampled and taxonomically well studied, yielding a large dataset of 19,042 specimens from 60 samples. The specimens represent 176 species-level and 99 genus-level taxa comprising 135 small mammal species and 47 large mammals. A detailed lithostratigraphy and new magnetostratigraphic and radiometric datings provide an excellent frame for these biotic data. Therefore, we test and evaluate the informal biozonation scheme that has been traditionally used for biostratigraphic correlations within the basin. Based on the analysis of the huge dataset, a formalised biostratigraphic scheme is proposed. It comprises the Cricetops dormitor Taxon Range Zone (Rupelian), subdivided into the Allosminthus khandae Taxon Range Subzone and the Huangomys frequens Abundance Subzone, the Amphechinus taatsiingolensis Abundance Zone (early Chattian), the Amphechinus major Taxon Range Zone (late Chattian), subdivided into the Yindirtemys deflexus Abundance Subzone and the Upper Amphechinus major T. R. Z., and the Tachyoryctoides kokonorensis Taxon Range Zone (Aquitanian). In statistical analyses, samples attributed to these biozones form distinct clusters, indicating that each biozone was also characterised by a distinct faunal type

Biodiversity and Evolutionary Development of Oligocene-Pliocene Lagomorphs (Lagomorpha, Mammalia) of Mongolia

Lagomorphs (pikas and hares) are an ancient group of small mammals originated in Asia in the Paleocene-Eocene. The earliest evidence of their presence in Mongolia is dated to the Early Oligocene. The taxa flourished during the Late Oligocene, Miocene and Pliocene; at the Late Pliocene they were reduced both in their diversity and in abundance. No data on lagomorph are known from the Pleistocene and Holocene, though there are 7 taxa of lagomorphs present in the modern fauna. Altogether, more than 50 lagomorph species, extinct at present, are known to have existed in Mongolia since the Oligocene through the Late Pliocene