new papers in Acta Geologica Sinica: Ningchengopterus,Shidaisaurus, Nyctosaurus and dentary diastemae in

[jigruiz@unizar.es]

http://www3.interscience.wiley.com/journal/118902578/home

Junchang LÜ. 2009. A Baby Pterodactyloid Pterosaur from the Yixian  
Formation of Ningcheng, Inner Mongolia, China. Acta Geologica Sinica,  
Volume 83 Issue 1, 1-8.

ABSTRACT
A new baby pterodactyloid pterosaur with soft tissue preserved,  
Ningchengopterus liuae gen. et sp. nov., is erected based on a nearly  
complete skeleton with a skull. It was characterized by the skull,  
slightly longer than the combined length of the dorsal and sacral  
vertebrae; 50 teeth (including upper and lower jaws); short  
mid-cervical vertebrae; the humerus and the scapula, equal to that of  
the wing metacarpal in length; the ulna and the femur, equal to that  
of the first and third wing phalanx in length, respectively. The  
similar ratio of the wing phalanx 2 to wing phalanx 1 of  
Ningchengopterus and Eosipterus implies that Ningchengopterus may be  
close to the ctenochasmatid pterosaur. However, it may also imply that  
the isometrically growing of the first two wing phalanges exists among  
some pterosaurs.
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Xiao-chun WU, Philip J. CURRIE, Zhiming DONG, Shigang PAN, Tao WANG.  
A. 2009.  New Theropod Dinosaur from the Middle Jurassic of Lufeng,  
Yunnan, China. Acta Geologica Sinica, Volume 83 Issue 1, 9-24.

ABSTRACT
A new theropod dinosaur, Shidaisaurus jinae gen. et sp. nov., has been  
described on the basis of an incomplete skeleton. The specimen was  
found near the base of the Upper Lufeng Formation (early Middle  
Jurassic) in Yunnan, China. It is the first theropod dinosaur from the  
Middle Jurassic of Yunnan. Shidaisaurus jinae is distinguishable from  
other Jurassic theropods by certain features from the braincase, axis,  
and pelvic girdle. The absence of any pleurocoels in the axis or in  
any anterior dorsal vertebrae suggests that the new Lufeng theropod is  
relatively primitive and more plesiomorphic than most of the Middle to  
Late Jurassic theropods from China. Most Chinese taxa of Jurassic  
theropod dinosaurs have not been well described; a further detailed  
study will be necessary for us to determine their phylogenetic  
relationships with Shidaisaurus jinae.
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Lida XING, Jianghao WU, Yi LU, Junchang LÜ, Qiang JI. 2009.  
Aerodynamic Characteristics of the Crest with Membrane Attachment on  
Cretaceous Pterodactyloid Nyctosaurus. Acta Geologica Sinica, Volume  
83 Issue 1, 25-32.

ABSTRACT
The Nyctosaurus specimen KJ1 was reconstructed under the hypothesis  
that there is a membrane attached to the crest; the so-called headsail  
crest. The aerodynamic forces and moment acting on the headsail crest  
were analyzed. It was 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 the headsail crest and body's center of gravity.  
Three scenarios were tested for comparison: the crest with membrane  
attachment, the crest without membrane attachment and the absence of a  
cranial crest. It was shown that the aerodynamic characteristics  
(increasing, maintaining and decreasing thrusts and moment) would have  
almost disappear in flight for the crest without membrane attachment  
and was non-existent without the cranial crest. It is suggested from  
aerodynamics evidence alone that Nyctosaurus specimen KJ1 had a  
membrane attached to the crest and used this reconstructed form for  
auxiliary flight control.
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Katsuhiro KUBOTA, Yoshitsugu KOBAYASHI. 2009. Evolution of Dentary  
Diastema in Iguanodontian Dinosaurs. Acta Geologica Sinica, Volume 83  
Issue 1,  39-45.

ABSTRACT
The dentary diastema of iguanodontians has been considered to be  
related to its unique jaw mechanism for herbivorous adaptation. The  
dentary and diastema lengths of iguanodontians were measured and  
compared to elucidate the evolution of iguanodontian diastema. A gap  
in ratios between most non-hadrosaurid iguanodontians and hadrosaurids  
was observed, suggesting that all non-hadrosaurid iguanodontians,  
expect for Ouranosaurus nigeriensis and Protohadros byrdi, lack a  
diastema or have a short diastema, although some other taxa have been  
considered to have a long diastema in previous studies. In  
non-hadrosaurid iguanodontians, some large-sized forms, such as  
Iguanodon bernissartensis, Shuangmiaosaurus gilmorei, and possibly  
Eolambia caroljonesa, had a short diastema through ontogeny, whereas  
Ouranosaurus nigeriensis and Protohadros byrdi developed a long  
diastema convergently. The development of a long diastema of  
hadrosaurine hadrosaurids may be different from that of lambeosaurine  
hadrosaurids. Some hadrosaurunes (Edmontosaurus annectens,  
Edmontosaurus regalis, and Saurolophus angustirostris) may have  
developed a long diastema in the subadult stage and showed little  
elongation of dentary diastema through ontogeny. Lambeosaurines  
(Corythosaurus casuarius and Lambeosaurus lambei) tend to have a short  
diastema in the embryonic and subadult stages, and an elongated  
diastema from the subadult to adult stages.

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Jose Ignacio Ruiz-Omeñaca
Museo del Jurásico de Asturias (MUJA)
E-33328 Colunga, Spain
www.dinoastur.com
www.museojurasicoasturias.com
www.aragosaurus.com
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