Table of Content

15 June 2001, Volume 39 Issue 02

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THE SECOND THALATTOSAUR FROM THE TRIASSIC OF GUIZHOU, CMNA

LIU Jun, RIEPPEL, Olivier

2001, 39(02):  77-87. 

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A new specimen of Xinpusaurus (Xinpusaurus cf. X. suni Yin) from the Wayao Member, Falang Formation (early Late Triassic) of Guanling, Guizhou Province, southwestrn China, is described, and the diagnosis of that taxon is revised. This taxon was originally described as an ichthyosaur, but is in fact a thalattosaur. A preliminary phylogenetic analysis indicates potential trans-Pacific relationships of Xinpusaurus.

RECENT PROGRESS ON STUDY OF EOCENE MAMMALS IN YUANQU BASIN

HUANG Xue-Shi, WANG Jing-Wen, TONG Yong-Sheng

2001, 39(02):  88-97. 

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Yuanqu Basin in cenfral China is well-known for its rich Eocene mammals not only in China but also in the world. More than half a century workers both from China and abroad have done a lot in geology and paleontology. In recent years we found many important fossils not only in the old localites but also in several new ones. Among these new localites Huoshipo near Guojiazhuang Village, Wangmao Town, Yuanqu County is the most important one, where new primate and carnivorus fossils have been found. Hyrachyus sp., ? Lushilagus sp. and Propterodon irdinensis as well as primitive rodents existed in this locality demonsüate that there may be Middle Eocene Irdinmanhan deposit in Yuanqu Basin, which was unknown in the past In the present paper these new and important localites and fossils ar briefly introduced, and the whole and complete faunal lists (? middle Middle Eocene Irdinmanhan Guojiazhuang Fauna, late Middle Eocene Sharamurunian Rencun Fauna, latest Middle Eocene Naduan Zhaili Fauna and ? Late Eocene Ulangochuan Nanbaotou Fauna) so far known are proposed (see Chinese text).

EOCENE CTENODACTYLOIDS (RODENTIA, MANMALIA) FROM NEI MONGOL, CHINA

WANG Ban-Yue

2001, 39(02):  98-114. 

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The ctenodactyloids from the Eocene of Mongol include 10 species representing 4 genera (Gobiomys neimongolensis, G. exiguus sp. nov., G. cf. G. xiguus, G. asiaticus sp. nov., Gobiomys? spp., Advenimus cf. A. bohlini, A. cf. A. burkei, Yuomys sp. and Protataromys sp.). The new genus, Gobiomys, is erected based on the species, neimongolensis, which has previously been referred to Mergenomys. The main characters of Gobiomys are: incisive foramen large; P3 present; cheek teeth lower crowned, with distinct but not swollen main cusps and broad sinuses; non-molariform; upper molars wider than long, with rather developed metaloph; Ml and M2 with entoloph; on lower molars metaconid and entoconid inclining forwards and ectolophid and hypoconulid slightly buccally located. The main features of G. eyguus small size, zygomatic process of maxillary anterior to P3, absence of lingual part of posterior arm of protoconid, ann of entoconid and anterior cingulum on lower molars. In G. asiaticus the posterior edge of the zygomatic process of maxillary is buccal to P3; the molars have more developed lophs; the upper molars are relatively wide and have weaker metaconule; and the lower molars have more developed arm of entoconid and anterior cingulum. The new family, Gobiomyidae, includes Gobiomys, Mergenomys, Youngomys and Ctenodactyloidea gen. nov. from Kazakhstan [see Wang et al., (MS)]. In the family the lower jaw lacks upper crest of masseteric fossa. The cheek teeth are brachydont and more bunodont than lophodont. P3 is usually present. P4/p4 are nonmolariform. On the upper molars the protoconule is absent, the metaloph extends towards protocone or absent and the metaconule is usually well-developed. The p4 has no metalophid. On lower molars the posterior arm of protoconid extends rather posteriorly and die am of entoconid is weak or absent. The ectolophid is near centrally located and has no mesoconid. The Gobiomyidae represent the sister group to the Ctenodactylidae.

EOCENE SUOIDS (ARTIODACTYLA, MANMALIA) FROM BOSE AND YONGLE BASINS, CHINA, AND THE CLASIFICATION AND EVOLUTION OF THE PALEOGENE SUOIDS

LIU Li-Ping

2001, 39(02):  115-128. 

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The earliest fossil suoid collection of the world from Guangxi, China, is identified as four taxa. Eocenchoerus gen. nov. is assigned to Suidae based primarily on the presence of a talon on M3. The Eocene suid indicates that the origin of Suidae is as early as that of Palaeochoeridae and Tayassuidae. The family Palaeochoeridae is accepted to group the Old World palaeochoerids, Siamochoerus viriosus sp. nov. and Huaxiachoerus guangxiensis gen. et sp. nov. are included in it, and Huaxiachoerus is considered close to Cynorca. A single upper molar is identified as a tayassuid, and is close to the typical tayassuid Perchoerus. If Cynorca and Perchoerus are indeed the root members of the two major evolutionary radiation of the World tayassuids, the New World tayassuids should evolve from their Old World ancestors. The diversified suoid group in the Asian Late Eocene suggests the split of Suidae, Palaeochoeridae and Tayassuidae might begin at the Middle Eocene or earlier period.

NEW MATERIALS OF CHILOTHERIUM M / (PERRISODACTYLA, RMNOCEROTIDAE) FROM THE LATE MlOCENE OF FUGU，SHAANXI

DENG Tao

2001, 39(02):  129-138. 

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The new materials in the present paper have abundant skull and mandible specimens, and try improve a deeper recognition to Ch. wimani for us. These new specimens show that Ch. wimani has a relatively particular position in the genus Chilotherium. It has very little separated parietal crests, a strongly concave cranial dorsal profile, well-developed supraorbital tubercles，and a high occipital surface, which indicate that Ch. wimani is the most primitive one in the known species of the genus Chilotherium.

FOSSIL MAMMALS OF EARLY PLEISTOCENE FROM NINGYANG, SHANDONG PROVINCE

ZHANG Zhao-Qun

2001, 39(02):  139-150. 

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REVIEW OF THE 40Ar-39Ar DATES OF THE JEHOL GROUP BY SMITH ET AL.

JIN Fan

2001, 39(02):  151-156. 

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The dates reported by Smith et al. in 1995 are the first 40 Ar- 39 Ar ages for the Jehol Group in western Liaoning, Northeast China, which provide a considerably improved age calibration of the lowermost Yixian Formation of the Jehol Group, and indicate that the whole group was deposited entirely within the Early Cretaceous time. However, because Smith et al.' s report mistook the dates of three epigenetic igneous rock samples as the ages of the upper and lower parts of the Yixian Formation, respectively (samples 5, 10, 4), the isotopic dating results, as a whole, are perplexing and have been greatly misunderstood since they were published in 1995. In fact, those dates for the Jehol Group by Smith et al. represent the 40 Ar- 39 Ar ages of at least four horizons: 122.9 ± 0.3Ma (volcanics underlying the Daxinfangzi Bed of the Yixian Formation), 122.1 ± 0.2— 122.5 ± 0.3Ma (Ershilipu Bed of the Yixian Formation), 121.5 ± 0.9— 121.6 ± 0.5Ma (volcanic breccias above the Jingangshan Bed of the Yixian Formation), 120.8 ± 0.4— 121.4 ± 0.7Ma (epigenetic igneous rocks overlying or intruding into the Yixian Formation).