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 New Papers
 Theropod
(Dinosauria: Saurischia) tracks from Lower Cretaceous Yixian Formation at
Sihetun, Liaoning Province, China and Possible Track Makers
Li-da Xing 1*, Jerald D. Harris2,
Feng Xiangyang3, Zhang Zhi-jun3
1) Institute of Geology, Chinese Academy of Geological Sciences, Beijing,
100037, China
2) Physical Sciences Department, Dixie State College, 225 South 700 East, St.
George, Utah 84770, USA
3) Department of Palaeontology, Geological Museum of China, Beijing 100034,
China
Abstract: Herein we describe three and one half footprints that pertain
to Grallator isp. from the Lower Cretaceous Yixian Formation, Sihetun,
Liaoning Province, China. This is the first description of dinosaur footprints
from the Yixian Formation. The tracks were left by at least three individual
track makers. It is estimated from the tracks that the body lengths of the track
makers were 1.51 m, which is the average length of known theropods from the
Yixian Formation. The feet of Caudipteryx and Sinosauropteryx were
reconstructed. The former was more similar than the latter to the Grallator
isp. track outlines. Feet capable of registering Grallator morphotype
tracks may therefore have been widely distributed in small-medium sized
theropods (other than dromaeosaurids and troodontids) from the Yixian Formation.
Key words: Sihetun of Liaoning Province, Yixian Formation, Lower Cretaceous,
Grallator, Track Maker
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Grallator isp. |
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Aerodynamic Characteristics of the Crest with Membrane
Attachment on Cretaceous Pterodactyloid Nyctosaurus
XING Lida1*,
WU Jianghao2*, LU
Yi2, LÜ Junchang1
and JI Qiang1
1 Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037
2 School of Transportation Science and Engineering, Beijing University of
Aeronautics and Astronautics, Beijing 100083
Abstract: The Nyctosaurus specimen KJ1 is reconstructed under the
hypothesis that there is a membrane attached to the crest, the so-called
headsail crest. The aerodynamic forces and moments acting on headsail crest are
then analyzed. It is shown that KJ1 might adjust the angle of the headsail crest
relative to the air current as one way to generate thrust (one of the
aerodynamic forces, used to overcome body drag in forward flight) and that the
magnitude of the thrust and moment could vary with the gesture angle and the
relative location between the aerodynamic center of headsail crest and body’s
center of gravity. Three scenarios are tested for comparison to each other: the
crest with membrane attachment, the crest without membrane attachment and the
absence of cranial crest. It is shown that the aerodynamic characteristics
(increasing, maintaining and decreasing thrusts and moments) would almost
disappeared in flight for the crest without membrane attachment and none
existent without the cranial crest. It is suggested from aerodynamics evidence
alone that Nyctosaurus specimen KJ1 had membrane attached to the crest
and used this reconstructed form for auxiliary flight control.
Key words: aerodynamic forces and moments, flight dynamics,
Nyctosaurus, headsail crest
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Nyctosaurus KJ (illustration by Chuang
Zhao and Lida Xing) |
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Papers
- XING Lida*.2005.Jehol Biota—A Mecca for Mesozoic Life Evolu
tion. Chinese Journal of Nature Vo1.27 No.1:20-24.(in Chinese, English abstract)
[Down]
- LÜ Junchang*, GAO Yubo, XING Lida, Li Zhixin, SUN Zhenyuan. 2007. New species of
Huaxiapterus from the Early Cretaceous of western Liaoning. Acta Geologica Sinica (English edition),
81(5): 683–687.[English abstract and Image]
(in English)
- XING Lida*, WANG Fengping, PAN Shigang, CHEN Wei. 2007
. The Discovery of Dinosaur Footprints from the Middle Cretaceous Jiaguan Formation of Qijiang County, Chongqing
City. Acta Geologica Sinica (Chinese edition), 81(11): 1591–1602.
(in Chinese, English abstract)
[English abstract and Image]
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- Xing L D*, Peng G Z, Shu C K. Stegosaurian skin impressions from the Upper Jurassic Shangshaximiao Formation, Zigong, Sichuan, China: A new observation. Geological Bulletin of China,
2008, 27(7):1049-1053.
(in Chinese, English abstract)
[English summary]
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- XING Lida*, WU Jianghao*, LU Yi, LÜ Junchang and JI Qiang. 2009. Aerodynamic
Characteristics of the Crest with Membrane Attachment on Cretaceous
Pterodactyloid Nyctosaurus. Acta Geologica Sinica (English edition),
83(1): 25-32.
(in English)
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- Xing L D*, Harris JD, Toru S, Masato F, Dong ZM, Discovery
of Dinosaur Footprints from the Lower Jurassic Lufeng Formation of
Yunnan Province, China and New Observations on Changpeipus.
2009, Geological Bulletin of China. 28(1):16-29.
[Abstract & Images]
(in English)
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- XING Lida*, Jerald D. Harris, Feng Xiangyang, Zhang Zhijun.
Theropod (Dinosauria: Saurischia) tracks from Lower Cretaceous Yixian
Formation at Sihetun, Liaoning Province, China and Possible Track Makers.
2009, Geological Bulletin of China. 28(6):705-712. (in
English)
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- XING Lida*, Jerald D. Harris,
Dong Zhiming, Lin Youli, Chen Wei, Guo Shengbin, Ji Qiang.
Ornithopod (Dinosauria: Ornithischia) Tracks from the Upper Cretaceous
Zhutian Formation in Nanxiong Basin, China and General Observations on Large
Chinese Ornithopod Footprints.
2009, Geological Bulletin of China. 28(7)13-27. (in
English)
Papers in
Press..
- Xing Lida, Dong Hui, Peng Guangzhao, Shu Chunkang, Hu Xiaodong,
Jiang Hua.A Scapular Fracture in Yangchuanosaurus hepingensis (Dinosauria:
Theropoda), Geological Bulletin of China. 2009.
- Xing Lida, Ye Yong, Shu Chunkang, Peng Guangzhao, You Hailu.
2009. Structure, Orientation and Finite Element Analysis of the Tail Club of
Mamenchisaurus hochuanensis. Acta Geologica Sinica (English edition)
Dino
illustration
- Cover illustration for
Jin Meng, Yaoming Hu.etc.2006.A Mesozoic
gliding mammal from northeastern China.Nature,2006,444:7121
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