罗哲西教授07年再发《自然》文章发现新哺乳动物化石

　　

生物通综合：来自美国自然历史卡内基博物馆（Carnegie Museum of Natural History），中国科学院地质与地球物理研究所的研究人员在我国内蒙古宁城道虎沟地区发现了一对保存完好的蜀兽科哺乳动物化石，这一发现以确凿的证据证明该地区产有蝾螈、真叶肢介、翼龙等化石的地层时代为中侏罗世。这一研究成果公布在11月1日出版的《Nature》杂志上。

领导这一研究的是美国自然历史卡内基博物馆古脊椎动物分部的馆长罗哲西博士，其早年毕业于南京大学，现为南京大学的客座教授，参予这一研究的还包括中国地质科学院地质研究所季强博士，袁崇喜博士。

今年3月同样是在《Nature》杂志上，罗哲西博士通过在河北省北部发现的一中生代eutriconodont(Yanoconodon allini)，提出中耳骨（middle ear bones）是由一Meckel软骨与下颚骨相连的，这为研究早期哺乳动物Hox基因作用模式提供了重要依据。

在11月份的这项研究种，研究人员在宁城道虎沟地区髫髻山组中部的凝灰质粉砂岩中发现了哺乳动物化石，化石从头到尾长约11厘米，保存了头颅和头后骨骼，分为正模和副模。根据其形态特征，研究小组将其归入蜀兽科，并命名为“粗壮假碾磨齿兽（新属、新种）”（Pseudotribosrobustus）。化石有上颌门齿2颗以上，犬齿1颗、前臼齿5颗、臼齿3颗；下颌门齿4颗、犬齿1颗、前臼齿5颗、臼齿3颗。其上臼齿的三个齿尖呈三角形模式。下臼齿以三角座的三角形齿尖模式为特征。研究小组根据对假碾磨齿兽的研究，认为蜀兽类与澳洲楔齿形哺乳动物的关系要比其他任何中生代哺乳动物类群更亲近。

内蒙古宁城道虎沟地区是我国研究燕辽生物群的经典地区之一，产有丰富的晚中生代化石，常见者有蝾螈、翼龙、兽脚类恐龙、哺乳动物、昆虫、叶肢介植物等。长期以来，我国学者对道虎沟地区产出的这些化石地层的时代归属意见分歧很大。少数学者认为该地层的时代为早白垩世（义县阶），所产的化石归于热河生物群。但大多数学者认为，该地层的时代为中侏罗世，所产的化石应归于燕辽生物群。众所周知，蜀兽科哺乳动物在世界各地分布较广，在欧洲主要分布于中侏罗世地层中，我国四川发现的董氏蜀兽产于中侏罗世上沙溪庙组。季强博士说，宁城道虎沟地区新发现的蜀兽科哺乳动物以直接的古生物证据再次证明，该地层的时代为中侏罗世，所产的化石无疑应当归于燕辽生物群，这对我国北方东部地区晚中生代陆相地层的精确划分和对比将具有重要意义。

原文摘要：
Nature 450, 93-97 (1 November 2007) |
doi:10.1038/nature06221; Received 3 April 2007; Accepted 3 September 2007
Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals
『Abstract』

Nature 446, 288-293 (15 March 2007) | 
doi:10.1038/nature05627; Received 4 August 2006; Accepted 29 January 2007
A new eutriconodont mammal and evolutionary development in early mammals  [Abstract]

附：
罗哲西博士

Post-doctoral Fellow, 1989-91, Harvard University
Ph.D., 1989, University of California at Berkeley
B.S., 1982, Nanjing University (China) 

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Email: [e-mail]

General Research Interests: 

- Vertebrate Paleontology 
- Evolutionary Morphology of Vertebrates 
- Systematic Biology 

Research Projects:

Evolution of Hearing in Whales: Evolution of ear structures and hearing specializations in toothed whales and baleen whales. 
Early Fossil Mammals: Their phylogenetic relationships and morphological evolution. 
Triassic–Jurassic Faunas: Vertebrate faunal transition from the Triassic to the Jurassic. 
Recent Publications:

Ji, Q., Z.-X. Luo, C.-X. Yuan, and A. R. Tabrum. 2006. A swimming mammaliaform from the Middle Jurassic and ecomorphological diversification of early mammals. Science 311: 1123-1127. E-print (376 Kb PDF) (supporting online material available via Science Web site) 

Li, G., and Z.-X. Luo. 2006. A Cretaceous symmetrodont therian with some monotreme-like postcranial features. Nature 439:195-200. E-print (772 Kb PDF) (supporting online material available via Nature Web site) 

Luo, Z.-X., and J. R. Wible. 2005. A Late Jurassic digging mammal and early mammalian diversification. Science 308:103-107. E-print (489 Kb PDF) (supporting online material available via Science Web site) 

Kielan-Jaworowska, Zofia, Richard L. Cifelli, & Zhe-Xi Luo. 2004. Mammals from the Age of Dinosaurs - Origins, Evolution, and Structure. Columbia University Press, New York. Pp. i-xv; 1-630. (More information is available on the Web site for Columbia University Press) 

Luo, Z.-X., Q. Ji, J. R. Wible and C-X. Yuan. 2003. An Early Cretaceous Tribosphenic mammal and metatherian evolution. Science 302:1934-1940. E-print (3.7 Mb PDF) (supporting online material available via Science Web site) 

Luo, Z.-X., Z. Kielan-Jaworowska, R. L. Cifelli. 2002. In Quest for A Phylogeny of Mesozoic Mammals. Acta Palaeontologica Polonica. 47(1): 1-78. E-print (3.6 MB PDF) (Supplementary Information: Data Matrix (25 Kb .mtx file) & PAUP Search Results (23 Kb .log file)) 

Ji, Q., Z.-X. Luo, C-X. Yuan, J. R. Wible, J.-P. Zhang, & J. A. Georgi. 2002. The earliest known eutherian mammal. Nature 416: 816-822. E-print (757 Kb PDF) (supplementary information available via Nature Web site) 

Luo, Z.-X. 2001. Inner ear and its bony housing in tritylodonts and implications for evolution of mammalian ear. Pp. 81-97. In: F. A. Jenkins et al. (eds.), Studies in Organismic and Evolutionary Biology in Honor of A. W. Crompton. Bulletin of Museum of Comparative Zoology, Harvard University. 156(1): 81-97. 

Luo, Z.-X., A. W. Crompton and A-L. Sun. 2001. A new mammaliaform from the Early Jurassic of China and evolution of mammalian characteristics. Science 292: 1535-1540. E-print (supporting online material available via Science Web site) 

Luo, Z.-X., R. C. Cifelli and Z. Kielan-Jaworowska. 2001. Dual evolution of tribosphenic mammals. Nature 409: 53-57. E-print (supplementary information available via Nature Web site) 

Tang, F., Z.-X. Luo, Z.-H. Zhou, H.-L. You, J. A. Georgi, Z.-L. Tang, and X.-Z. Wang. 2001. Biostratigraphy and Paleoenvironment of the Dinosaur-bearing Sediments in Lower Cretaceous of Mazongshan Area, Gansu Province, China. Cretaceous Research 22: 115-129. E-print (1.5 Mb PDF) 

Luo, Z.-X. 2000. Evolution: in search of the whales’ sisters. Nature 404: 235 - 239. E-print (241 Kb PDF) 

Luo, Z.-X. and P. D. Gingerich. 1999. Transition from terrestrial ungulates to aquatic whales: transformation of the basicranium and evolution of hearing. Papers on Paleontology (Monograph) 31: 1-98. Museum of Paleontology, University of Michigan, Ann Arbor, Michigan. 

Ji, Q., Z.-X. Luo, and S. Ji. 1999. A Chinese triconodont mammal and mosaic evolution of mammalian skeleton. Nature 398:326-330. E-print (supplementary information available via Nature Web site) 

Geisler, J. H., and Z.-X. Luo. 1998. Cranial vascular evolution in mesonychids and cetaceans and the phylogenetic position of cete. Pp. 161-212. In: J. G. M. Thewissen (ed.), Evolutionary Emergence of Whales. Plenum Press, New York. 

Luo, Z.-X., and K. Marsh. 1996. Petrosal (periotic) and inner ear of a Pliocene kogiine whale (Kogiinae, Odontoceti): Implications on relationships and hearing evolution of toothed whales. Journal of Vertebrate Paleontology 16:328–348. 

Luo, Z.-X., and E. R. Eastman. 1995. The petrosal and inner ear structures of a squalodontoid whale: Implications for evolution of hearing in odontocetes. Journal of Vertebrate Paleontology 15:431–422. 

Luo, Z.-X., and A.W. Crompton. 1994. Transformations of the quadrate (incus) through the transition from non-mammalian cynodonts to mammals. Journal of Vertebrate Paleontology 14:341–374. 


Luo, Z.-X. 1994. Sister taxon relationships of mammals and the transformations of the diagnostic mammalian characters. Pp. 98-128 in: In the Shadow of Dinosaurs-Early Mesozoic Tetrapods (N. C. Fraser & H.-D. Sues, eds.). Cambridge University Press.