A newly discovered Jiaguan Formation(Lower Cretaceous) tracksite from the Linjiang region of Guizhou Province, China, reveals the first example of a Cretaceous track morphotype attributable to the non-avian theropod i...A newly discovered Jiaguan Formation(Lower Cretaceous) tracksite from the Linjiang region of Guizhou Province, China, reveals the first example of a Cretaceous track morphotype attributable to the non-avian theropod ichnogenus Gigandipus, here named Gigandipus chiappei ichnosp nov. The theropod dominated locality also reveals the second report of the avian theropod ichnogenus Wupus, one of the largest avian traces currently known from the Lower Cretaceous. The Linjiang site provides evidence to support previous interpretations of a distinctive Lower Cretaceous theropod-dominated ichnofauna that was widespread in China and East Asia and highlights the similarity between Lower Cretaceous theropod ichnotaxa in East Asia and those found in the Lower Jurassic both in East Asia and elsewhere. These similarities in turn create various ichnotaxonomic challenges familiar to researchers working on theropod tracks, and we recommend caution in the naming of new theropod ichnotaxa at the ichnogenus level.展开更多
Theropods, mesoeucrocodiles and pterosaurs (along with titanosaurian sauropods) are found in two overbank flood deposited mottled muds/shale units (alternated by meandering river deposited sandstone unit) of the lates...Theropods, mesoeucrocodiles and pterosaurs (along with titanosaurian sauropods) are found in two overbank flood deposited mottled muds/shale units (alternated by meandering river deposited sandstone unit) of the latest Maastrichtian (67 - 66 Ma) Vitakri Formation, Barkhan District, Balochistan, Pakistan. These vertebrates coexisted under the Cretaceous-Paleogene boundary line of control and became extinct as mass extinction. Previously these taxa lack the detail description but here theropods, mesoeucrocodiles and pterosaur from Pakistan are being described well with large photographs which provide better understanding of fauna from Pakistan and comparison with coeval taxa from Indo-Pakistan subcontinent. These fauna with associated cranial and postcranial skeletons are significant for Gondwanan paleobiogeography and phylogenetic studies.展开更多
A new theropod dinosaur, Shidaisaurusjinae 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 Y...A new theropod dinosaur, Shidaisaurusjinae 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 Shidaisaurusjinae.展开更多
Vitakrisaurus saraiki abelisauroid theropod dinosaurs reported from Pakistan and extended distribution into India. Vitakrisaurus saraiki is medium to large sized theropod which is represented by associated vertebral a...Vitakrisaurus saraiki abelisauroid theropod dinosaurs reported from Pakistan and extended distribution into India. Vitakrisaurus saraiki is medium to large sized theropod which is represented by associated vertebral and limb elements and especially hand elements. Out of 14 small to large bodied theropods from Indo-Pakistan subcontinent, only less than half of these are restricted to some common elements. Vitakrisaurus saraiki theropod of Pakistan is based on associated vertebral and limb elements especially hand including articulated carpals, metacarpals, phalanges and claws which are significant for Gondwanan paleobiogeographic link, comparisons and systematic.展开更多
A fossil theropod dinosaur discovered in China is thought to be vegetarian, in sharp contrast with its meat-eating cousins, according to research published in Nature on September 19,2002.……
Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. B...Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. Bed to bed gypsum samplings (and their chemical analyses) of huge gypsum deposits from Sulaiman foldbelt is a base for industrialist and also planers to develop cement and gypsum industries to increase export and foreign exchange for the development of area and Pakistan. Low and high grade sedimentary iron deposits, silica sand and uranium host rocks and their extensions in Sulaiman and Kirthar foldbelts are presented. Anomalies of a few base metals arise as a result of geochemical exploration carried at part of Loralai District of Balochistan. Theropod dinosaurs were frequent in India, while Poripuchian titanosaurs (Sauropoda, Dinosauria) were frequent in Pakistan. Besides some ichnotaxa, many bone taxa such as 1 titanosauriform, 14 titanosaurian sauropod (including one new titanosaur), and 3 theropod dinosaurs are established from Pakistan. Among these 12 titanosaur species and 3 theropod species are named in about 10 km<sup>2</sup> area of Vitakri dome and 2 titanosaur species are named in about a few hundred square meter area of Mari Bohri (Kachi Bohri) which is about 10 km westward from Vitakri dome. Pakistan is a unique country which discoverd 14 diversified titanosaurs in a short area and also in a short period (67 - 66 million years ago/Ma). About 400 bones found from a few meter thick upper part of upper shale horizon of latest Maastrichtian Vitakri Formation which is base for titanosaur taxa. Cranial material is in low fraction (but include significant diverse snouts), caudal vertebrae are prominent, the cervicals, dorsals and sacrals have significant numbers, forelimb and hind limb bones have balanced fraction. Humeri, femora and tibiae are most common. To know the position of Pakistani titanosaurs among titanosaurs and sauropods, there is a need to extend list of characters for phylogenetic analyses. This broad feature list should include main characters of titanosaurs from Pakistan and also from global world.展开更多
A new Middle Jurassic tracksite dominated by non-avian theropod footprints from the Wangjiashan Formation in Pingchuan District,Baojishan Basin,Gansu Province has yielded a unique trackway with four consecutive manus-...A new Middle Jurassic tracksite dominated by non-avian theropod footprints from the Wangjiashan Formation in Pingchuan District,Baojishan Basin,Gansu Province has yielded a unique trackway with four consecutive manus-pes sets.Only three previous examples,all Early Jurassic in age,of theropod trackways are known with convincing examples of manus tracks and in each case,only two tracks were recorded in association with pes tracks with metatarsal impressions and pelvic traces indicating crouching behavior.Thus,this is the first example of manus tracks registered while a theropod trackmaker was walking.This unique configuration is here designated as Grallator pingchuanensis ichnosp.nov.which shows the trackmaker forelimbs registering in a wide straddle gait,much wider than the pes trackway width.G.pingchuanensis confirms previous reports that theropods could occasionally register tridactyl,ectaxonic manus traces.In the case of the Pingchuan trackway,the short step indicates an animal moving at a slow speed,probably due to a soft substrate.展开更多
Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late ...Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus(Late Triassic) and Liujianpus(Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger(Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation.展开更多
The trackway of a swimming theropod (ichnogenus Characichnos) is reported from the Lower Cretaceous Feitianshan Formation of Sichuan, China. These swim tracks help confirm that non-avian theropods were capable of forg...The trackway of a swimming theropod (ichnogenus Characichnos) is reported from the Lower Cretaceous Feitianshan Formation of Sichuan, China. These swim tracks help confirm that non-avian theropods were capable of forging moderately deep bodies of water. The trackway occurs on the same surface as a typical walking trackway of a sauropod (ichnogenus Brontopodus). Both occurrences are the first reported from the Cretaceous of Sichuan, and the swim tracks are the first well-preserved example of a Characichnos trackway from China. Additionally, a theropod walking trackway and several ornithopod walking trackways (similar to the ichnogenus Caririchnium) occur in the same horizon. The ornithopod trackways show a parallel orientation, suggesting gregarious behavior of the trackmakers, which may have been iguanodontiforms and/or hadrosauriforms. The co-occurrence of theropod swim tracks and theropod walking tracks suggests a fluctuation of water depth within a distinct time span.展开更多
"Splitting" and "lumping" are perpetual problems in vertebrate, especially dinosaur, ichnotaxonomy. Chinese dinosaur ichnotaxonomy, which began in 1940, provides a series of interesting case studies, highlighting ..."Splitting" and "lumping" are perpetual problems in vertebrate, especially dinosaur, ichnotaxonomy. Chinese dinosaur ichnotaxonomy, which began in 1940, provides a series of interesting case studies, highlighting the dual problems of historical and dubious ichnotaxonomy. Chinese Mesozoic tetrapod track types have been placed into 63 ichnospecies (one Triassic, 28 Jurassic, and 34 Cretaceous), exclusive of other, non-type ichnospecies or ichnotaxa identified from China. Fifty-two (~83%) of these 63 tetrapod ichnospecies were placed in monospecific ichnogenera. At the ichnogenus level, we prune---either by recognizing nomina dubia or by synonymy--17 from the list of 53 dinosaurian ichnogenera (a 32% reduction), leaving 36 ichnotaxa that we consider valid. Most of the cuts affect Jurassic theropod ichnotaxa, which are reduced from 23 to only nine because most ichnogenera are subjective junior synonyms of Grallator and Eubrontes. Fewer Chinese Cretaceous ichnotaxa (only six of 21 ichnogenera) are obvious nomina dubia or subjective synonyms, suggesting greater east Asian endemism during this time. Because ichnospecies differences are subtle, we provisionally retain ichnospecies as valid pending detailed comparative analyses of congeneric ichnospecies. This synthesis is long overdue and is necessary to address problems of historical and provincial ichnotaxonomy, which severely hamper comparisons of tetrapod ichnofaunas in space and time.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funded by the National Natural Science Foundation of China(Grant Nos.41772008,41790455)the Fundamental Research Funds for the Central Universities(Grant No.2652017215)the State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)(Grant No.173127)
文摘A newly discovered Jiaguan Formation(Lower Cretaceous) tracksite from the Linjiang region of Guizhou Province, China, reveals the first example of a Cretaceous track morphotype attributable to the non-avian theropod ichnogenus Gigandipus, here named Gigandipus chiappei ichnosp nov. The theropod dominated locality also reveals the second report of the avian theropod ichnogenus Wupus, one of the largest avian traces currently known from the Lower Cretaceous. The Linjiang site provides evidence to support previous interpretations of a distinctive Lower Cretaceous theropod-dominated ichnofauna that was widespread in China and East Asia and highlights the similarity between Lower Cretaceous theropod ichnotaxa in East Asia and those found in the Lower Jurassic both in East Asia and elsewhere. These similarities in turn create various ichnotaxonomic challenges familiar to researchers working on theropod tracks, and we recommend caution in the naming of new theropod ichnotaxa at the ichnogenus level.
文摘Theropods, mesoeucrocodiles and pterosaurs (along with titanosaurian sauropods) are found in two overbank flood deposited mottled muds/shale units (alternated by meandering river deposited sandstone unit) of the latest Maastrichtian (67 - 66 Ma) Vitakri Formation, Barkhan District, Balochistan, Pakistan. These vertebrates coexisted under the Cretaceous-Paleogene boundary line of control and became extinct as mass extinction. Previously these taxa lack the detail description but here theropods, mesoeucrocodiles and pterosaur from Pakistan are being described well with large photographs which provide better understanding of fauna from Pakistan and comparison with coeval taxa from Indo-Pakistan subcontinent. These fauna with associated cranial and postcranial skeletons are significant for Gondwanan paleobiogeography and phylogenetic studies.
基金supported by grants from the Canadian Museum of Nature and the National Science and Engineering Research Counsel of Canada (Grant No:203091-98).
文摘A new theropod dinosaur, Shidaisaurusjinae 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 Shidaisaurusjinae.
文摘Vitakrisaurus saraiki abelisauroid theropod dinosaurs reported from Pakistan and extended distribution into India. Vitakrisaurus saraiki is medium to large sized theropod which is represented by associated vertebral and limb elements and especially hand elements. Out of 14 small to large bodied theropods from Indo-Pakistan subcontinent, only less than half of these are restricted to some common elements. Vitakrisaurus saraiki theropod of Pakistan is based on associated vertebral and limb elements especially hand including articulated carpals, metacarpals, phalanges and claws which are significant for Gondwanan paleobiogeographic link, comparisons and systematic.
文摘 A fossil theropod dinosaur discovered in China is thought to be vegetarian, in sharp contrast with its meat-eating cousins, according to research published in Nature on September 19,2002.……
文摘Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. Bed to bed gypsum samplings (and their chemical analyses) of huge gypsum deposits from Sulaiman foldbelt is a base for industrialist and also planers to develop cement and gypsum industries to increase export and foreign exchange for the development of area and Pakistan. Low and high grade sedimentary iron deposits, silica sand and uranium host rocks and their extensions in Sulaiman and Kirthar foldbelts are presented. Anomalies of a few base metals arise as a result of geochemical exploration carried at part of Loralai District of Balochistan. Theropod dinosaurs were frequent in India, while Poripuchian titanosaurs (Sauropoda, Dinosauria) were frequent in Pakistan. Besides some ichnotaxa, many bone taxa such as 1 titanosauriform, 14 titanosaurian sauropod (including one new titanosaur), and 3 theropod dinosaurs are established from Pakistan. Among these 12 titanosaur species and 3 theropod species are named in about 10 km<sup>2</sup> area of Vitakri dome and 2 titanosaur species are named in about a few hundred square meter area of Mari Bohri (Kachi Bohri) which is about 10 km westward from Vitakri dome. Pakistan is a unique country which discoverd 14 diversified titanosaurs in a short area and also in a short period (67 - 66 million years ago/Ma). About 400 bones found from a few meter thick upper part of upper shale horizon of latest Maastrichtian Vitakri Formation which is base for titanosaur taxa. Cranial material is in low fraction (but include significant diverse snouts), caudal vertebrae are prominent, the cervicals, dorsals and sacrals have significant numbers, forelimb and hind limb bones have balanced fraction. Humeri, femora and tibiae are most common. To know the position of Pakistani titanosaurs among titanosaurs and sauropods, there is a need to extend list of characters for phylogenetic analyses. This broad feature list should include main characters of titanosaurs from Pakistan and also from global world.
基金supported by the Scientific Innovative Funds and Special Funds for Discipline Construction of Gansu Agricultural University(Grant Nos.066-056001 and GAU-XKJS-2018-159)the National Natural Science Foundation of China(Grant Nos.41790455 and 41772008)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2652017215)the State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences)(Grant No.173127)
文摘A new Middle Jurassic tracksite dominated by non-avian theropod footprints from the Wangjiashan Formation in Pingchuan District,Baojishan Basin,Gansu Province has yielded a unique trackway with four consecutive manus-pes sets.Only three previous examples,all Early Jurassic in age,of theropod trackways are known with convincing examples of manus tracks and in each case,only two tracks were recorded in association with pes tracks with metatarsal impressions and pelvic traces indicating crouching behavior.Thus,this is the first example of manus tracks registered while a theropod trackmaker was walking.This unique configuration is here designated as Grallator pingchuanensis ichnosp.nov.which shows the trackmaker forelimbs registering in a wide straddle gait,much wider than the pes trackway width.G.pingchuanensis confirms previous reports that theropods could occasionally register tridactyl,ectaxonic manus traces.In the case of the Pingchuan trackway,the short step indicates an animal moving at a slow speed,probably due to a soft substrate.
基金supported by the National Natural Science Foundation of China (Grant No.41772008)the State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology, CAS)(Grant No.173127)and the comprehensive geological and mineral survey in Wumeng mountainous area conducted by China Geological Survey (Grant No.121201010000150002)
文摘Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus(Late Triassic) and Liujianpus(Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger(Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation.
基金supported by Key Laboratory of Evolutionary Systematics of Vertebrates,Chinese Academy Sciences (2011LESV008)
文摘The trackway of a swimming theropod (ichnogenus Characichnos) is reported from the Lower Cretaceous Feitianshan Formation of Sichuan, China. These swim tracks help confirm that non-avian theropods were capable of forging moderately deep bodies of water. The trackway occurs on the same surface as a typical walking trackway of a sauropod (ichnogenus Brontopodus). Both occurrences are the first reported from the Cretaceous of Sichuan, and the swim tracks are the first well-preserved example of a Characichnos trackway from China. Additionally, a theropod walking trackway and several ornithopod walking trackways (similar to the ichnogenus Caririchnium) occur in the same horizon. The ornithopod trackways show a parallel orientation, suggesting gregarious behavior of the trackmakers, which may have been iguanodontiforms and/or hadrosauriforms. The co-occurrence of theropod swim tracks and theropod walking tracks suggests a fluctuation of water depth within a distinct time span.
基金supported by the Grant-in-Aid for Scientific Research of the Japan Society for the Promotion of Science(to Masaki Matsukawa,no.1183303,1999-2000)the Grant-in Aid for University and Society Collaboration of the Japanese Ministry of Education, Science,Sports and Culture(to Masaki Matsukawa,no. 11791012,1999-2001)+2 种基金The Shandong portion of this study was supported financially,in part,by the National Natural Science Foundation of China grant no.40972005 to Rihui LiThe Nei Mongol portion of this study was supported by a grant from the National Natural Science Foundation of China(40872005) to Jianjun Lithe Beijing Museum of Natural History,with supplemental support from the Dinosaur Tracks Museum,University of Colorado Denver
文摘"Splitting" and "lumping" are perpetual problems in vertebrate, especially dinosaur, ichnotaxonomy. Chinese dinosaur ichnotaxonomy, which began in 1940, provides a series of interesting case studies, highlighting the dual problems of historical and dubious ichnotaxonomy. Chinese Mesozoic tetrapod track types have been placed into 63 ichnospecies (one Triassic, 28 Jurassic, and 34 Cretaceous), exclusive of other, non-type ichnospecies or ichnotaxa identified from China. Fifty-two (~83%) of these 63 tetrapod ichnospecies were placed in monospecific ichnogenera. At the ichnogenus level, we prune---either by recognizing nomina dubia or by synonymy--17 from the list of 53 dinosaurian ichnogenera (a 32% reduction), leaving 36 ichnotaxa that we consider valid. Most of the cuts affect Jurassic theropod ichnotaxa, which are reduced from 23 to only nine because most ichnogenera are subjective junior synonyms of Grallator and Eubrontes. Fewer Chinese Cretaceous ichnotaxa (only six of 21 ichnogenera) are obvious nomina dubia or subjective synonyms, suggesting greater east Asian endemism during this time. Because ichnospecies differences are subtle, we provisionally retain ichnospecies as valid pending detailed comparative analyses of congeneric ichnospecies. This synthesis is long overdue and is necessary to address problems of historical and provincial ichnotaxonomy, which severely hamper comparisons of tetrapod ichnofaunas in space and time.
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。
基金supported by Geophysical Team of Sichuan Bureau of Geological and Mineral Investigation and Exploration, Chengdu, Sichuan, Chinathe 2013 support fund for graduate student’s science and technology innovation from China University of Geosciences (Beijing), China~~
基金supported by the National Natural Science Foundation of China(No.41790455,41772008)the National Geographic Society,USA(No.EC0768-15)+1 种基金the Fundamental Research Funds for the Central Universities(No.2652017215)the State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences)(No.173127)