A new stegosaur species, Jiangjunosaurusjunggarensis, gen. et sp. nov., is erected based on a specimen collected from the Upper Jurassic upper section of the Shishugou Formation in the Junggar Basin, Xinjiang, China. ...A new stegosaur species, Jiangjunosaurusjunggarensis, gen. et sp. nov., is erected based on a specimen collected from the Upper Jurassic upper section of the Shishugou Formation in the Junggar Basin, Xinjiang, China. It represents the first stegosaur from the Jurassic of Xinjiang and increases the diversity of the dinosaur fauna in the Shishugou Formation. The new genus is characterized by symmetrical and proportionally wide tooth crowns, a sub-rectangular axial neural spine seen in lateral view, and large openings on the lateral surfaces of the cervical centra. A preliminary character analysis suggests that this new taxon is more derived than the Middle Jurassic stegosaur Huayangosaurus but more primitive than most other known stegosaur species.展开更多
The Middle-Late Jurassic transition period is a critical period for the evolution of terrestrial vertebrates,but the global fossil record from this time is relatively poor.The Shishugou Fauna of this period has recent...The Middle-Late Jurassic transition period is a critical period for the evolution of terrestrial vertebrates,but the global fossil record from this time is relatively poor.The Shishugou Fauna of this period has recently produced significant fossil remains of dinosaurs and other vertebrate groups,some representing the earliest known members of several dinosaurian groups and other vertebrate groups and some representing the best-known specimens of their group.These discoveries are significant for our understanding of the origin and evolution of several vertebrate lineages.Radiometric dating indicates that the fauna is aged approximately 159-164 Ma.Comparisons with other similarly-aged terrestrial faunas such as Shaximiao and Yanliao show both taxonomic similarities and differences between these faunas and indicate that the Junggar deposits might have preserved the most complete vertebrate fossil record for a Middle-Late Jurassic Laurasian terrestrial fauna.展开更多
中国西部准噶尔盆地东北缘中侏罗世晚期到晚侏罗世早期沉积的石树沟组(Eberth et al.,2001)产出过巨型的蜥脚类恐龙化石(Russell and Zheng,1993),但产出的兽脚类恐龙个体则相对较小(Currie and Zhao,1993)。我们近年来在石树沟组中采...中国西部准噶尔盆地东北缘中侏罗世晚期到晚侏罗世早期沉积的石树沟组(Eberth et al.,2001)产出过巨型的蜥脚类恐龙化石(Russell and Zheng,1993),但产出的兽脚类恐龙个体则相对较小(Currie and Zhao,1993)。我们近年来在石树沟组中采集到大量脊椎动物化石(Clark et al.,2006),其中包括许多零散的骨骼和牙齿标本。本文报道一个产自石树沟组上部的兽脚类牙齿化石(IVPP V 15310),对于全面了解石树沟脊椎动物群具有一定意义。V 15310保存了一个近乎完整的上颌齿或下颌齿的齿冠。它具有典型兽脚类恐龙牙齿的特征:强烈侧扁,向后弯曲,前后缘有锯齿。齿冠有几种不同的磨蚀面:齿尖磨蚀成近圆形,靠近齿尖的齿冠前缘有一较大的平的磨蚀面,锯齿也受到不同程度的磨蚀。V 15310很大,相关的测量数据和一些白垩纪的巨型兽脚类恐龙牙齿的测量数据相近。依据我们定义的一个定量评估锯齿大小的指标(锯齿大小指数),得出V 15310的锯齿大小指数非常小,与霸王龙相似,这与锯齿和齿冠大小具有反比关系的结论是一致的(Farlow et al,1991)。V 15310的另外一些形态特征对于推断它在兽脚类中的系统位置也提供了帮助。这些特征包括后缘锯齿明显高于前缘锯齿以及齿冠的唇侧和舌侧都有微弱的釉质褶皱。根据牙齿大小、釉质褶皱的发育程度以及锯齿的形态(Sereno et al.,1996;Chure et al.,1999;Holtz,2004),V 15310被归入中国盗龙类。其中,后缘锯齿和前缘锯齿的基部长度近似,但前者明显高于后者这一特征组合可能是中国盗龙类的一个鉴定特征。这一特征组合也见于四川的中国盗龙类。相比而言,V 15310在已报道的侏罗纪兽脚类恐龙牙齿中尺寸最大(Smith,2005;Smith et al.,2005),大小接近白垩纪的一些巨型兽脚类恐龙牙齿。新材料的发现表明兽脚类至少在晚侏罗世早期就已演化出了这种巨型体型。展开更多
基金This work was supported by the National Natural Science Foundation of China；the U. S. National Science Foundation （EAR）；the National Geographic Society；the Jurassic Foundation, the Hilmar Sallee bequest, George Washington University；the Chinese Academy of Sciences.
文摘A new stegosaur species, Jiangjunosaurusjunggarensis, gen. et sp. nov., is erected based on a specimen collected from the Upper Jurassic upper section of the Shishugou Formation in the Junggar Basin, Xinjiang, China. It represents the first stegosaur from the Jurassic of Xinjiang and increases the diversity of the dinosaur fauna in the Shishugou Formation. The new genus is characterized by symmetrical and proportionally wide tooth crowns, a sub-rectangular axial neural spine seen in lateral view, and large openings on the lateral surfaces of the cervical centra. A preliminary character analysis suggests that this new taxon is more derived than the Middle Jurassic stegosaur Huayangosaurus but more primitive than most other known stegosaur species.
基金supported by the National Natural Science Foundation of China(42288201,41688103,40830210,41120124002)the National Science Foundation Division of Earth Sciences(NSF EAR 0310217,0922187,1636753)the National Geographic Society。
文摘The Middle-Late Jurassic transition period is a critical period for the evolution of terrestrial vertebrates,but the global fossil record from this time is relatively poor.The Shishugou Fauna of this period has recently produced significant fossil remains of dinosaurs and other vertebrate groups,some representing the earliest known members of several dinosaurian groups and other vertebrate groups and some representing the best-known specimens of their group.These discoveries are significant for our understanding of the origin and evolution of several vertebrate lineages.Radiometric dating indicates that the fauna is aged approximately 159-164 Ma.Comparisons with other similarly-aged terrestrial faunas such as Shaximiao and Yanliao show both taxonomic similarities and differences between these faunas and indicate that the Junggar deposits might have preserved the most complete vertebrate fossil record for a Middle-Late Jurassic Laurasian terrestrial fauna.
文摘中国西部准噶尔盆地东北缘中侏罗世晚期到晚侏罗世早期沉积的石树沟组(Eberth et al.,2001)产出过巨型的蜥脚类恐龙化石(Russell and Zheng,1993),但产出的兽脚类恐龙个体则相对较小(Currie and Zhao,1993)。我们近年来在石树沟组中采集到大量脊椎动物化石(Clark et al.,2006),其中包括许多零散的骨骼和牙齿标本。本文报道一个产自石树沟组上部的兽脚类牙齿化石(IVPP V 15310),对于全面了解石树沟脊椎动物群具有一定意义。V 15310保存了一个近乎完整的上颌齿或下颌齿的齿冠。它具有典型兽脚类恐龙牙齿的特征:强烈侧扁,向后弯曲,前后缘有锯齿。齿冠有几种不同的磨蚀面:齿尖磨蚀成近圆形,靠近齿尖的齿冠前缘有一较大的平的磨蚀面,锯齿也受到不同程度的磨蚀。V 15310很大,相关的测量数据和一些白垩纪的巨型兽脚类恐龙牙齿的测量数据相近。依据我们定义的一个定量评估锯齿大小的指标(锯齿大小指数),得出V 15310的锯齿大小指数非常小,与霸王龙相似,这与锯齿和齿冠大小具有反比关系的结论是一致的(Farlow et al,1991)。V 15310的另外一些形态特征对于推断它在兽脚类中的系统位置也提供了帮助。这些特征包括后缘锯齿明显高于前缘锯齿以及齿冠的唇侧和舌侧都有微弱的釉质褶皱。根据牙齿大小、釉质褶皱的发育程度以及锯齿的形态(Sereno et al.,1996;Chure et al.,1999;Holtz,2004),V 15310被归入中国盗龙类。其中,后缘锯齿和前缘锯齿的基部长度近似,但前者明显高于后者这一特征组合可能是中国盗龙类的一个鉴定特征。这一特征组合也见于四川的中国盗龙类。相比而言,V 15310在已报道的侏罗纪兽脚类恐龙牙齿中尺寸最大(Smith,2005;Smith et al.,2005),大小接近白垩纪的一些巨型兽脚类恐龙牙齿。新材料的发现表明兽脚类至少在晚侏罗世早期就已演化出了这种巨型体型。
