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The paleoenvironment of the middle Pliocene Udunga fauna has been estimated by many workers to date based on the composition of the mammalian fauna. In this short article we tried the paleoenvironmental analysis of the Udunga fauna using the mesowear method to equiids (Hipparion) cheek teeth. The result indicate the openland environment for the middle Pliocene Udunga. On the other hand, Postschizotherium of Udunga is likely differs from P. chardini, discovered from the late Pliocene to the early Pleistocene of Nihewan, Shanxi Province, China, suggesting the possibility of the new species for this specimen.

Artiodactyla is the most dominant mammal in the Udunga fauna, and more than 2000 specimens have been recognized in the fossil materials to date. In this small study we provisionally identified ten taxa, including four species of cervids and six species of bovids based on antler and horn morphology, but the identification operation has not yet been completed. Most of the artiodactyl specimens are of dental and bone fragments, so it is very hard to identify the taxa on the genus and/or species level. In order to classify the postcranial materials we tried the statistical analyses on four kinds of the hind limb bones, such as astragalus, distal tibia, calcaneus, and naviculocuboid. Although we could not get the sufficient result from this work, we classify the specimens into several groups. These analyses would be useful for higher taxa classification of fossil artiodactyls.

We provide notes of carnivore fossils from the middle Pliocene Udunga fauna, Transbaikal area, Russia. The fossil carnivore assemblage consists of more than 200 specimens including eleven genera. Ursus, Parailurus, Parameles, and Ferinestrix are representative of the animals of thermophilic forest biotopes. On the other hand, Chasmaporthetes and Pliocrocuta are probably specialized in open environment. The prosperity both in foresal and semiarid carnivores indicate that the Udunga fauna is comprised of mosaic elements.

Over 500 rhinoceros fossils were collected from Udunga (MN15–16a), Transbaikalia, Russia and housed at the Southern Scientific Center, Rostov-on-Don, Russia. Both qualitative and statistic analyses applied for the fossils indicate that they are composed of a single species. 16 individuals are recognized in the collection. The Udunga rhinoceros is allocated into the tribe Rhinocerotini based on the anteriorly extended articulation between the ulna and the semilunar. Although the ossification of nasal septum is unknown, it can be assigned to Stephanorhinus based on the loss of the functional anterior dentition. In addition to the reduced incisor, the quantitative analyses for the dental and the postcranial materials show the similarities between the Udunga materials and S. megarhinus. The quantitative analyses for the central metapodials strongly suggest that the former species is more closely related to the European species than to the Turkish one. It also implies that the rhinoceroses were migrated to Transbaikal area directly from Europe.

A New Miocene vertebrate fossil locality was found in Mae Soi, Chiang Mai Province. A nearly complete gomphothere skeleton was excavated from this site, together with several fragmental mammalian fossils. The gomphothere from Mae Soi could be either Archaeobelodon or Gomphotherium. The age of the deposits in which this gomphothere skeleton occured is provisionally dated to the Early or Middle Miocene. Partial skeletons of rhinocerotids were found in Na Sai, which is a well known locality of the Miocene in Northern Thailand. The rhinocerotid from this locality has been assigned to Gaindatherium, but cranial fragments included in a new skeleton suggest that the rhinocerotid from Na Sai could not be Gaindatherium but, rather, some other primitive genus of Rhinocerotidae. Further analysis of the skeletal elements of this rhinocerotid is necessary.

In February 1999, we visited several fossil yielding areas in northern Thailand. These areas, except for the Hab Pu Dai Cave Deposit locality, are of Miocene age (Ducrocq et al. 1994, Saegusa et al. 1999). A number of fossils were collected at these localities during our fieldwork in February 1999.The most extensively examined areas were Mae Soi and Sob Mae Tham, where we recognized 17 and 20 fossil localities, respectively. Our field survey suggests that there is still a good possibility to find new fossil sites in northern Thailand. In this article, we provide field information on each of these fossil localities.

The Namurungule Formation yields a large amount of mammals of a formerly unknown and diversified vertebrate assemblage of the late Miocene. The Namurungule Formation has been dated as approximately 7 to 10 Ma. This age agrees with the mammalian assemblage of the Namurungule Formation. Sedimentological evidence of this formation supports that the Namurungule Formation was deposited in lacustrine and/or fluvial environments. Numerous equid and bovid remains were found form the Namurungule Formation. These taxa indicate the open woodland to savanna environments. Assemblage of the Namurungule Fauna indicates a close similarity to those of North Africa, Southwest and Central Europe, and some similarity to Sub-Paratethys, Siwaliks and East Asia faunas. The Namurungule Fauna was the richest among late Miocene (Turolian) Sub-Saharan faunas. From an analysis of Neogene East Africa faunas, it became clear that mammalian faunal assemblage drastically has changed from woodland fauna to openland fauna during Astaracian to Turolian. The Namurungule Fauna is the forerunner of the modern Sub-Saharan (Ethiopian) faunas in savanna and woodland environments.

The postcranial samples of Hipparion (Equidae, Perissodactyla) collected by the Paleontological Expedition of Kyoto University in 1973 from Maragheh, northwest Iran were compared with other materials stored in other institutes in Europe. Three morphotypes could be distinguished in the third metapodials by their size and proportions. They are: 1) medium to large robust morphotype; 2) large and slender morphotype; and 3) small and slender morphotype. The first morphotype corresponds to H. prostylum, the second to H. urmiense, and the third to H. moldavicum recognized in the same locality by cranial materials. It is crucial procedure for taxonomy and phylogenetic analysis of extensively deversified Late Miocene Hipparion in Eurasia to make clear association in a single taxon between cranial and postcranial morphotypes from a fossil locality, resulting the increase of morphological characters and data on the functional tie between facial and locomotory features.

Cranial skeletons of Hipparion collected from Maragheh, northwest Iran were studied. On the basis of facial and dental morphology, four morphotypes of skull were recognized in Maragheh hipparions, namely, 1) H. gettyi; 2) H. moldavicum; 3) H. prostylum; and 4) H. urmiense. The morphotypes in the cranial elements were correlated with those in the postcranial bones. By this the correspondence between the facial morphology and postcranial proportions are attained, allowing increase of characters available for studies on functional morphology and taxonomy. Based on those characters, we discussed phylogenetic relationships of the Maragheh Hipparion with other Eurasian late Miocene hipparions. They show similarity to those from the Turolian beds in northern China.