Table of Content

15 June 1997, Volume 35 Issue 02

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ANTIARCHAN REMAINS OF TARIM BASIN, XINJIANG AND RELATED STRATIGRAPHY

WANG Junqing, ZOU Yisheng, ZHAO Zhixin

1997, 35(02):  81-87. 

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The antiarchan specimen described in this paper was collected from a drilling about 6000m below ground level in the north margin of Tarim Basin. The fossil — bearing strata belong to the Upper Devonian.

BIOMECHANICAL PROPERTIES OF DINOSAUR EGGSHELLS(VI)—THE STABILITY OF DINOSAUR EGGSHELL UNDER EXTERNAL PRESSURE

ZHAO Zikui, MA Hezhong

1997, 35(02):  88-101. 

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It is well known that the patterns of dinosaur egg arrangement within the clutch differ from group to group (Young, 1965; Zhao, 1975, 1979; Zhao and Li, 1993). Some types such as elongatoolithid and hypsilophodontid eggs were laid regularly in nest. The long axis of these eggs forms certain angle with the ground (Plate I). But as for others, they were disorderly arranged in the nest. Zhao et al. (1994) advanced that dinosaur eggshells could be considered as rotational ' thin shell. When the dinosaur eggs were laid, and buried in sand for incubation, they were subjected to distributive pressure. Once the pressure comes to the critical value pcr , the eggshell will subside and then break. Here p cr is called the critical pressure of instability. It has been demonstrated that Variation between pcr of different kinds of dinosaur eggshells existed (Ma and Zhao, 1994). This suggests that arrangement patterns of dinosaur eggs in nests might have something to do with the eggshell ' s ability to resist external pressure. The purpose of this paper is to discuss the relationship between the pattern of egg arrangement in the nest and the critical pressure of its eggshell, and five types of dinosaur eggshells are available.

FINE STRUCTURE OF DENTAL TISSUES IN TEETH OF SAURISCHIAN TYRANNOSAURID AND SQUAMATE MOSASAURID

Yoshizou ISHIKAWA, Yasutomo IWZI-LIAO, Yoshikage HIGASHI

1997, 35(02):  102-109. 

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Teeth of saurischian tyrannosaurid and squamate mosasaurid are studied mainly by scanning electron microscopy. The teeth of both diapsids are cone —shaped homodontic teeth mediolaterally compressed and curved posteriorly. The sharp cutting edges at both anterior' and posterior aspects of tyrannosaurid tooth are serrated with invagination of a quite thin aprismatic enamel layer. Fissures and pits of the invaginations are packed with what is possibly a layer of fossilized organic substance. In contrast, similar serrated cutting edges are only observed at the basal portion or lepidosaurian mosasaurid teeth. The present scanning electron microscopy (SENI) observes a. similar intermediate type orthodentine (tubular dentine) with ill —developed peritubular dentine of both extinct reptiles. SEM reveals that dentinal tubules are regularly branched only in the vicinity of the flat dentino —enamel junction in tyrannosaurid tubular dentine, bul are complicatedly branched in the rnid and superficial —layer of mosasaurid dentine. The ryesent study also shows a few dentinal tubules invaded the enamel layer, with a similar configuration and an evident distribution of interglobular dentine beneath the thin enamel layer of both reptiles. Based on the present fine structure study, we elucidates some histological similarities and dissimilarities of the enamer and dentine in the reptilian tyrannosaurid and mosasaurid of different infraclasses.

A NEW PALAEANODONT (MAMMALIA) FROM THE EARLY EOCENE OF WUTU BASIN, SHANDONG PROVINCE

TONG Yongsheng, WANG Jingweli

1997, 35(02):  110-120. 

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A new palaeanodont, Auroratherium sinense, was discovered in the Wutu Formation in 1993. Palaeanodonts are a rare group of fossorially adapted mammals, which up to now has been found solely in North America from the Paleocene to the Oligocene. This initial discovery suggests that palaeanodonts may also be widely, but rarely, distributed in the Paleogene of Asia. Associated with the specimen are other mammals, such as Changlelestes (Soricomorpha), Mesodmops (Multituberculata), Alagomyid, Paramyid and ctenodactyloid rodents, carpolestid primates, and primitive perissodactyls.

NOTES ON THE AGE OF CHAGANBULAGE FORMATION IN HAOSIBULDU BASIN, NEI MONGOL, CHINA

WANG Banyue, WANG Peiyu

1997, 35(02):  121-129. 

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Summary can be seen in PDF.

NOTE ON LATE CENOZOIC LAGOMORPHS OF DANJIANG RESERVOIR AREA IN HUBEI AND HENAN

LIU Liping, ZHENG Shaohua

1997, 35(02):  130-144. 

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Three species of lagomorghs found in 1994 from Danjiang Reservoir area in Hubei and Henan are described in the present paper. Alloptox xichuanensis sp. nov. represented by an upper and a lower jaw is considered to be the earliest record of the genus. One p3 is her referred to Ochotonoides complicidens. Another p3 is treated to a new species, Pliopentalagus progressitus, which may be the most advanced representative of the genus. The fossil — bearing beds are also discussed herein.

NOTE ON A FOSSIL SKULL OF HYSTRIX MAGNA PEI, 1987 (RODENTIA, MAMMALIA) FROM CHONGZUO, GUANGXI

GUO JianWei

1997, 35(02):  145-153. 

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Here described a skull of Hystrix collected by Guangxi Investigation Team of IVPP in 1956 from the Pleistocene fissure filling of the Dutou Cave, Chongzuo, Guangxi. The specimen shows differences from the all known species with the skulls. Though no tooth was preserved, the length and the width of the alveolus of left P4 (10.5mm & 11.0mm) are very similar to the measurements of left P4 of H. magna, which was also found in the Early Pleistocene deposit in the caves of Guangxi. So the specimen is referred to H. magna temporally.