Browsing by Author "Bi, Shundong."
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Item Eucricetodon (Rodentia, Mammalia) from the late Oligocene of the Junggar Basin, northern Xinjiang, China. (American Museum novitates, no. 3665)(New York, NY : American Museum of Natural History., 2009) Maridet, Olivier.; Wu, Wenyu.; Ye, Jie.; Bi, Shundong.; Ni, Xijun.; Meng, Jin (Paleontologist).New specimens of Eucricetodon are described from the late Oligocene Tieersihabahe Formation of the Junggar basin, northern Xinjiang, China. The relatively abundant material documents the morphological variation within Asian species of the genus. The taxon, identified as E. aff. E. caducus, is similar to E. caducus from the Oligocene of Kazakhstan and China and E. occasionalis from the Early Miocene of Kazakhstan. It also shows noticeable resemblances to E. longidens from the Late Oligocene of Europe whose origin is currently in debate. The study confirms the strong morphological affinity between Asian and European species of Eucricetodon and suggests that the evolutionary trends among paracricetodontines are probably more complex than previously assumed, especially with the new forms discovered from the last decade. A systematic revision of Eurasian paracricetodontines at species level is needed to understand their evolutionary history.Item New distylomyid rodents (Mammalia, Rodentia) from the early Miocene Suosuoquan Formation of northern Xinjiang, China. (American Museum novitates, no. 3663)(New York, NY : American Museum of Natural History., 2009) Bi, Shundong.; Meng, Jin (Paleontologist); Wu, Wenyu.; Ye, Jie.; Ni, Xijun.Three new distylomyid species, Distylomys burqinensis, Prodistylomys wangae, and P. lii, are described from the Suosuoquan Formation, early Miocene, of Xinjiang Province, northwestern China. Previously unknown cranial materials and upper dentitions add new information for the higher-level taxonomy of distylomyid rodents. Based on these new discoveries, the family Distylomyidae is resurrected. These fossils demonstrate that distylomyids have a combination of primitive "ctenodactylid" characters and derived hystricognathous ones, possibly indicating a close affinity with South American caviomorph rodents and thereby offering new evidence to challenge the hypothesis that the traditional "Ctenodactyloidea" are monophyletic. Prodistylomys lii was recovered from Suosuoquan mammal assemblage III (magnetostratigraphically dated as 21.69-21.16 Mya) at the Chibaerwoyi locality. Distylomys burqinensis and Prodistylomys wangae were collected from a new fossiliferous locality, Locality XJ200601 of Burqin County. The composition of the fauna from this new locality suggests that it represents an assemblage younger than Suosuoquan mammal assemblage III. Preliminary comparison with other faunas suggests that the assemblage is of early Miocene age, approximately 20 Mya old, and is a new fossil level within the Suosuoquan Formation.Item A new species of Megacricetodon (Cricetidae, Rodentia, Mammalia) from the Middle Miocene of northern Junggar Basin, China ; American Museum novitates, no. 3602(New York, NY : American Museum of Natural History, 2008) Bi, Shundong.; Meng, Jin (Paleontologist); Wu, Wenyu.Dental, mandibular, and postcranial specimens of Megacricetodon yei n. sp., are described. The new specimens, including the complete dentition, mandible, and partial forelimb and hindlimb, represent the most complete materials known for the genus, provide valuable information concerning the interspecific variation of the genus, and lead to the reassessment of the suprageneric position of Megacricetodon. Megacricetodon yei is characterized by having medium-size, clearly split anterocone of M1, presence of the labial spur of the anterolophule and the posterior spur of the paracone in some M1s, medium to long mesoloph in M1-2, frequent occurrences of double protolophules, transverse or posteriorly directed metalophule of M2, and single anteroconid of the m1. Megacricetodon yei is more closely related to Megacricetodon (= Aktaumys) dzhungaricus than to any other species of Megacricetodon, but is more derived than the latter. Based on the new information, the validity of the genus Aktaumys is discussed. The postcranial features of Megacricetodon yei show clear adaptations for terrestrial habits, but as in many ground-dwelling rodents living in burrows, it could also climb or dig. The associated fauna has been correlated to Tongxin fauna from the adjacent part of China and the Belometchetskya fauna of north Caucasus, equivalent to early Middle Miocene age, or MN 6 correlative. The stage of evolution of Megacricetodon yei is consistent with the faunal correlation. Dental, mandibular, and postcranial specimens of Megacricetodon yei n. sp., are described. The new specimens, including the complete dentition, mandible, and partial forelimb and hindlimb, represent the most complete materials known for the genus, provide valuable information concerning the interspecific variation of the genus, and lead to the reassessment of the suprageneric position of Megacricetodon. Megacricetodon yei is characterized by having medium-size, clearly split anterocone of M1, presence of the labial spur of the anterolophule and the posterior spur of the paracone in some M1s, medium to long mesoloph in M1-2, frequent occurrences of double protolophules, transverse or posteriorly directed metalophule of M2, and single anteroconid of the m1. Megacricetodon yei is more closely related to Megacricetodon (5 Aktaumys) dzhungaricus than to any other species of Megacricetodon, but is more derived than the latter. Based on the new information, the validity of the genus Aktaumys is discussed. The postcranial features of Megacricetodon yei show clear adaptations for terrestrial habits, but as in many ground-dwelling rodents living in burrows, it could also climb or dig. The associated fauna has been correlated to Tongxin fauna from the adjacent part of China and the Belometchetskya fauna of north Caucasus, equivalent to early Middle Miocene age, or MN 6 correlative. The stage of evolution of Megacricetodon yei is consistent with the faunal correlation.