Table of Content

15 September 2012, Volume 50 Issue 3

Previous Issue    Next Issue

COMMENTS ON PALEOGENE LOCALITIES AND STRATIGRAPHY IN THE ERLIAN BASIN, NEI MONGOL, CHINA

WANG Yuan-Qing, MENG Jin, JIN Xun

2012, 50(3):  181-203. 

Asbtract ( )   PDF (2376KB) ( )  

Related Articles | Metrics

The Erlian Basin is located in central Nei Mongol(InnerBecause the definitions of some formations vary among localities or areas, the following dis-cussion of locality names, and the stratigraphic subdivisions and correlations is organized geo-graphically in order to avoid further confusion(refer to Fig.1 for the localities). Mongolia), near the China-Mongolia border. Its coordinates are approximately 420-440N and 110°-114E(Jiang,1983).The Paleogene strata in the basin are well-exposed and fossiliferous. Since the 1920s, the Cen-tral Asiatic Expeditions of the American Museum of Natural History(CAE), the Sino-Soviet Paleontological Expedition, the Regional Geological Survey of Nei Mongol Autonomous Region, and the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (in collaboration with the American Museum of Natural History and the Carnegie Museum of Natural History in recent years) have investigated the Erlian Basin. Such work has established a stratigraphic framework and provided the basis for a number of proposed lithostratigraphic unit names. Several faunas from the Erlian Basin ha been the base of Asian Paleogene Land Mammal Ages that have been widely accepted(Luterbacher et al.,2004). The Erlian Basin has thus become an important area for the study of Asian Paleogene mammals, stratigraphy and related issues. For a long time, however, some confusion has existed regarding the usage oflocality names, and clarity has been lacking with respect to the definitions, subdivisions and correlative relationships of some lithostratigraphic units in the region. In the course of his study of Asian Paleogene tapiroids, Radinsky (1964) discussed the Eocene and Oligocene fossil localities in the Erlian Basin and questioned the stratigraphic assignments of some localities, but he failed to clarify the local stratigraphy. The purpose of this paper is to clarify some of the un-certainties that exist regarding both locality names and stratigraphy, based on our recent investigations and on comparisons of our new data with previous references and the CAE archives.

PROEGGYSODON GEN. NOV., A PRIMITIVE EOCENE EGGYSODONTINE (MAMMALIA, PERISSODACTYLA) FROM ERDEN OBO, SIZIWANGQI, NEI MONGOL, CHINA

BAI Bin, WANG Yuan-Qing

2012, 50(3):  204-218. 

Asbtract ( )   PDF (1741KB) ( )  

Related Articles | Metrics

Previously, rhinocerotoid eggysodontines have been confined to Oligocene deposits from Europe and Asia. Here we report a new primitive Late Eocene eggysodontine, Proeggysodon qiui gen. et sp. nov., from Erden Obo, Siziwangqi, Nei Mongol, China. Proeggysodon differs from other eggysodontines in being smaller; in having two pairs of well-developed, spatulate lower incisors, non-molarized lower premolars, a more lingually aligned cristid obliqua of p4, and an angled junction between the cristid obliqua and the hypolophid of each lower molar; and in lacking buccal cingulids on the lower cheek teeth. Furthermore, we propose that eggysodontines and forstercooperes are closely related, mainly because they share the following features: large and erect canine, relatively short diastema between canine and cheek teeth, and dorsoventrally deep and anteroposteriorly abbreviated symphysis associated with nearly vertically implanted incisors. The new specimen narrows the time gap between the Early to Middle Eocene forstercooperes and the Oligocene eggysodontines. The discovery of Proeggysodon in Asia also suggests that eggysodontines dispersed from this continent into Europe after the “Grande Coupure”.

NEW GOBIOLAGUS (MAMMALIA: LAGOMORPHA) MATERIAL FROM THE MIDDLE EOCENE OF ERDEN OBO (NEI MONGOL, CHINA)

Lucja FOSTOWICZ-FRELIK, LI Chuan-Kui, MENG Jin, WANG Yuan-Qing

2012, 50(3):  219-236. 

Asbtract ( )   PDF (3565KB) ( )  

Related Articles | Metrics

A new species of Gobiolagus (Lagomorpha: Palaeolagidae) from the Middle Eocene locality of Aliwusu (Erlian Basin, Nei Mongol, China) is described. Gobiolagusaliwusuensis sp. nov. is characterized by its medium size, accessory cusp on the anterior wall of P3 central lobe and by two distinct buccal cusps on P4. The material from Aliwusu constitutes the only record of Gobiolagus with complete upper dental rows, which contain previously unknown P2 and M3. This discovery adds new data on the morphology and diversification of Middle Eocene lagomorph fauna in Central Asia.

MIDDLE EOCENE CRICETIDS (RODENTIA, MAMMALIA) FROM THE ERLIAN BASIN, NEI MONGOL, CHINA

LI Qian

2012, 50(3):  237-244. 

Asbtract ( )   PDF (1182KB) ( )  

Related Articles | Metrics

 New cricetids (Pappocricetodon neimongolensis sp. nov., Pappocricetodon cf. P.zhongtiaensis, Pappocricetodon sp.) are reported from the basal strata of the Irdin Manha Formation in the Huheboerhe section in Nei Mongol, China. P. neimongolensis is characterized by the following features: presence of a P4 or DP4; anterocone small; anterior arm of protocone on M1 well-developed and connected to anterocone; distinct paraloph joining protoconule and paracone; protocone on M1 lacking posterior arm; posterior arm of protocone present on M2; hypocone of M3 prominent; protoconid generally positioned anterior to metaconid on m1; posterior arm of protoconid on m2 complete; m3 unreduced, with “S”-shaped ectolophid. P. neimongolensis is morphologically similar to the early cricetid Pappocricetodon antiquus. Pappocricetodon sp. has a prominent anterior lobe, andPappocricetodon cf. P. zhongtiaensis has a distinct mesoloph. These fossils suggest that cricetids were already diversified in the Middle Eocene, and probably originated earlier than the Irdinmanhan.

NEW MESONYCHID (MAMMALIA) MATERIAL FROM THE LOWER PALEOGENE OF THE ERLIAN BASIN, NEIMONGOL, CHINA

JIN Xun 

2012, 50(3):  245-257. 

Asbtract ( )   PDF (3027KB) ( )  

Related Articles | Metrics

Early Paleogene mesonychid specimens, recently collected from the Huheboerhe area and Bayan Ulan, eastern Erlian Basin, Nei Mongol (Inner Mongolia), are described in this paper. They represent six species and four genera, a few of the specimens are specifically indeterminate. Mesonyx nuhetingensis sp. nov., from the basal Arshanto Formation, differs from previously known species of Mesonyx in p4 being the longest lower cheek tooth and weak lingual cingula being present on p3 and p4, respectively. Other mesonychid specimens described in this paper are referred toDissacus serratus, Dissacus sp., Mesonyx uqbulakensis, Mongolonyx dolichognathusand Harpagolestes leei. General evolutionary trends seen in mesonychids from theErlian Basin show a gradual increase in body size and a change in feeding habits from active predation to scavenging.

CORYPHODONTIDS (MAMMALIA: PANTODONTA) FROM THE ERLIAN BASIN OF NEI MONGOL, CHINA, AND THEIR BIOSTRATIGRAPHIC IMPLICATIONS

MAO Fang-Yuan, WANG Yuan-Qing

2012, 50(3):  258-280. 

Asbtract ( )   PDF (4705KB) ( )  

Related Articles | Metrics

Coryphodontids(Mammalia: Pantodonta), as the most geographically widespread major group of extinct large herbivorous mammals, are among the most useful mammalian index fossils for drawing stratigraphic correlations in North America(Lucas,1984,1998; Uhen and Gingerich,1995). In Asia, however, confusion regarding their taxonomy and misinterpretations of the lithostratigraphy of the fossil-bearing units have made it difficult to use coryphodontids for this purpose. Given improved understanding of intraspecific variation and sexual dimorphism within this highly variable taxon (Uhen and Gingerich,1995; McGee,2001,2002; McGee and Turnbull,2010), and the availability of newly clarified lithostratigraphic correlations(Meng,1990; Meng et al.,2007; Wang et al.,2010) and a recently established framework for Asian mammalian biochronology(Sun et al.,2009), it is an opportune time to restudy Asian coryphodontids. Specifically, Erlian Basin, Nei Mongol, China is one of the most important regions in the world for research in Paleogene vertebrate paleontology and stratigraphy, and has yielded some well-preserved coryphodontid material that can provide plenty of detailed information and clarify some taxonomic problems. Based on this material, Eudinoceras has been revised as follows.

MIDDLE MIOCENE OCHOTONIDS (OCHOTONIDAE, LAGOMORPHA) FROM DAMIAO PLIOPITHECID LOCALITY, NEI MONGOL 

ZHANG Zhao-Qun, Anu KAAKINEN, WANG Li-Hua, Liu Li-Ping, LIU Yan, Mikael FORTELIUS

2012, 50(3):  281-292. 

Asbtract ( )   PDF (1232KB) ( )  

Related Articles | Metrics

Although highly diversified in their early history, only one genus in Ochotonidae,Ochotona, survives to the present. Ochotona is generally accepted to have originated from the Middle Miocene Bellatona. During the 2006–2010 field seasons, we found Miocene localities at Damiao, Siziwang Qi, Nei Mongol, which produced rich materials of ochotonids. Of these localities, DM01 (pliopithecid locality), dated by the paleomagnetic method and faunal comparison as late Middle Miocene (~12 Ma), yielded rich materials of the Bellatona-Bellatonoides-Ochotonagroup, and a large-sized relic form assigned to Desmatolagus moergenensis. The p3 morphology of the Bellatona-Bellatonoides-Ochotona complex conserves a similar tooth outline, but with distinct successive structures. The Bellatona form has two labial folds and no lingual fold on p3. The p3 ofBellatonoides form has one shallow anterolingual fold that is widely separated from the anterolabial fold. The p3 of Ochotona has a deep anterolingual fold that is closely connected with the anterolabial fold by a central bridge. The posterior process on M2 also shows progressive enlargement from Bellatona to Ochotona. Other cheek teeth of this complex are not distinguishable by either morphology or size. With only teeth found, we tentatively propose successive linear evolutionary relationships of the Bellatona-Bellatonoides-Ochotona complex, and Ochotona may have directly originated from Bellatonoides during the late Middle Miocene. The geological age of this fossil locality is consistent with the divergence time of Ochotona as estimated by molecular dating methods. 

ZOOGEOGRAPHY, MOLECULAR DIVERGENCE, AND THE FOSSIL RECORD – THE CASE OF AN EXTINCT FISHER, PEKANIAPALAEOSINENSIS (MUSTELIDAE, MAMMALIA), FROM THE LATE MIOCENE BAOGEDA ULA FORMATION, NEI MONGOL

WANG Xiao-Ming, Zhijie Jack TSENG, Gary T. TAKEUCHI

2012, 50(3):  293-307. 

Asbtract ( )   PDF (736KB) ( )  

Related Articles | Metrics

Elaine Anderson first established in the early 1970s a close relationship between the late Miocene Chinese Martes palaeosinensis and living North American fisher M. pennanti, based on their shared presence of an external rootlet on the upper carnassial. Such a recognition paved the way for their elevated status as a distinct genus of their own, Pekania, an implicit relationship increasingly corroborated by molecular phylogenetics, which tend to show that the living fisher is either a sister to the northern Holarctic wolverine (Gulo) or a stem group bracketed between Central and South American tayra (Eira) and a Gulo-Martes clade. We describe an upper jaw ofPekania palaeosinensis from the late Miocene (Baodean) Baogeda Ula Formation of Nei Mongol. We take this opportunity to review the molecular relationships, divergence time, and the fossil record of the Pekania clade. Although the Chinese records of the fishers are in close agreement with divergence time estimates of 5−8 Ma for the Pekania clade based on molecular clock estimates, a deep fossil record for the wolverines, on the other hand, suggests a much more ancient divergence time and by extension, for the fishers as well.