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1.
Mark P. Witton 《Cretaceous Research》2009,30(5):1293-1300
A new species of the sail-crested pterosaur Tupuxuara is described from the Santana Formation of Brazil, Tupuxuara deliradamus sp. nov. The holotype, a partial skull, and a larger, partial skull referred to the same taxon differs from Tupuxuara leonardii by having a nasoantorbital fenestra with an acutely-angled posterior border with a long, straight posterodorsal margin, a reclined cranium, and an orbit situated entirely in the ventral half of the nasoantorbitral fenestra. Unfortunately, neither specimen is comparable with the fragmentary rostrum representing Tupuxuara longicristatus. In addition, resolution of a recent nomenclatural problem over the correct name for the clade containing Tupuxuara and its sister taxon, Thalassodromeus, is provided. Both genera are used by different authors as the nomenclatural basis for the group, but “Tupuxuaridae” has never been explicitly erected as a new taxon, and therefore fails to meet ICZN criteria that new taxa are only valid if authors clearly indicate their intention to establish new names. By contrast, “Thalassodrominae” was explicitly erected as a name for the Thalassodromeus + Tupuxuara clade, thereby fulfilling all ICZN requirements for naming of a new taxon and making Thalassodromeus stand as the type genus for this group. 相似文献
2.
A Large Therizinosauroid （Dinosauria： Theropoda） from the Early Cretaceous of Northwestern China 总被引：2，自引：0，他引：2
LI Daqing PENG Cuo YOU Hailu Matthew C. LAMANNA Jerald D. HARRIS Kenneth J. LACOVARA ZHANG Jianping 《《地质学报》英文版》2007,81(4):539-549
We herein describe an associated partial postcranial skeleton of a theropod dinosaur discovered in the Lower Cretaceous Xinminpu Group of the Yujingzi Basin, in the Jiuquan area of Gausu Province, northwestern China. Features of its humerus, such as strongly expanded proximal and distal ends, a well developed medial tuberosity, distal condyles expressed on the humeral cranial surface, and a hypertrophied entepicondyle, definitively establish the therizinosauroid affinities of the specimen. It differs from other therizinosauroids in having a shallow, poorly demarcated glenoid fossa with a prominent rounded and striated tumescence on the dorsomedial surface of its scapular portion, and a pubis with a strongly concave cranial margin. It represents a new taxon, Suzhousaurus megatherioides gen. et sp. nov. Cladistic analysis recovers Suzhousaurus as the sister taxon of Nothronychus mckinleyi from the mid-Cretaceous of western North America; together, they are basal members of the Therizinosauroidea, more derived than the Early Cretaceous Falcarius and Beipiaosaurus but less derived than Alxasaurus and the Therizinosauridae. Along with ＂Nanshiungosaurus＂ bohlini from possibly coeval beds in the Mazongshan area of northern-most Gansu, Suzhousaurus represents one of the largest-known Early Cretaceous therizinosauroids, demonstrating that this clade attained considerable body size early in its evolutionary history. 相似文献
3.
The anatomy of an articulated juvenile specimen of the saurolophine hadrosaurid dinosaur Edmontosaurus annectens, LACM 23504, is described in detail. This individual consists of a partial skull and nearly complete articulated postcranium, collected from upper Maastrichtian strata of the Hell Creek Formation of Montana, USA. This study aims to help understand the ontogenetic morphological changes occurring in the cranium and postcranium of saurolophine hadrosaurids using E. annectens as a case study. Emphasis is placed on those morphological attributes that are ontogenetically variable via comparative osteology between the juvenile and the available adult specimens. It is observed that much of the cranial ontogenetic variation relates to the elongation of the skull and mandible. In the postcranium, most of the ontogenetic variation concentrates in the pectoral and pelvic girdles and the stylopodia. Not all the identified patterns of ontogenetic variation may be generalized to all hadrosaurids. The impact of ontogenetic variation on phylogenetically informative characters of saurolophine hadrosaurids is evaluated. It is concluded that, at least for Edmontosaurus annectens (and perhaps other saurolophine hadrosaurids), most characters used in phylogenetic inference of these animals are not affected by ontogeny. Thus, juvenile specimens are still a source of substantial character data suitable for use in phylogenetic analyses of saurolophine relationships. Nevertheless, it is recommended that ontogenetically variable characters are left as missing data in a character–taxon matrix when only juvenile material is available for a given saurolophine taxon. Scoring those characters based solely on juveniles is likely to decrease the accuracy of the phylogenetic inference. 相似文献
4.
本文描述了产自中国辽宁省北票市早白垩世义县组一新的伤齿龙类化石——柯氏辽宁猎龙(Liaoningvenator curriei gen. et sp. nov.)。它具有伤齿龙类以下特征: 数量众多且密集的上颌齿与下颌齿; 牙齿的齿冠与齿根之间显著收缩; 齿骨侧表面具有一沟, 营养孔位于该沟内; 远端尾椎背部的神经棘减弱为一个沟。它不同于其它伤齿龙类的特征主要为坐骨靴大, 侧面观近乎三角形, 坐骨闭孔突细长; 尾椎形态转变点位于第7尾椎。系统发育分析表明柯氏辽宁猎龙与短羽始中国羽龙(Eosinopteryx brevipenna)构成姊妹群, 位于同一分支内。它们具有如下共同特征: (1)上颌骨和下颌骨前面部分的牙齿前隆无锯齿; (2)颈肋较其相关节的椎体长; (3)肠骨前缘直。辽宁猎龙代表了辽西同等层位发现的第5个伤齿龙类。骨组织研究显示辽宁猎龙的骨骼已接近成熟, 死亡时至少4岁。它为该地区的基干伤齿龙类恐龙提供了新的解剖学信息, 并丰富了目前中国已知早白垩世伤齿龙类的多样性。 相似文献
5.
Elaphrosaurinae is an enigmatic clade of gracile ceratosaurian theropod dinosaurs known from the Late Jurassic of Africa (Elaphrosaurus bambergi) and Asia (e.g., Limusaurus inextricabilis), and the early Late Cretaceous of Argentina (Huinculsaurus montesi). Elaphrosaurinae is often placed within Noasauridae as the sister taxon to Noasaurinae, a clade of small-bodied theropods that lived in South America, Africa, Madagascar and India throughout much of the Cretaceous. Herein, we report the first evidence of Elaphrosaurinae from Australia: a nearly complete middle cervical vertebra from the upper Lower Cretaceous (lower Albian) Eumeralla Formation of Cape Otway, Victoria, Australia. The fact that this site would have been situated at ~76°S towards the end of the Early Cretaceous (~110–107 Ma) implies that elaphrosaurines were capable of tolerating near-polar palaeoenvironments, whereas its age indicates that elaphrosaurines persisted in Australia until at least the late Early Cretaceous. The new Australian elaphrosaurine, in tandem with the recently described Huinculsaurus montesi from the Cenomanian–Turonian of Argentina, implies that the spatiotemporal distribution of Elaphrosaurinae has heretofore been greatly underestimated. Historic confusion of elaphrosaurines with coelurosaurs, especially ornithomimosaurs, coupled with our generally poor understanding of noasaurid evolution, might explain the apparent dearth of fossils of this theropod clade worldwide. 相似文献
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7.
Stegosauria: a historical review of the body fossil record and phylogenetic relationships 总被引：2，自引：0，他引：2
Susannah C. R. Maidment 《Swiss Journal of Geoscience》2010,103(2):199-210
The first partial skeleton of a stegosaurian dinosaur was discovered in a brick pit in Swindon, UK in 1874. Since then, numerous
stegosaurian remains have been discovered from Europe, North America, Africa and Asia, and continue to be discovered regularly.
Stegosaurs are known from the Middle Jurassic to the Early Cretaceous; no definitive evidence of the clade is known from younger
deposits. New discoveries are improving our understanding of stegosaur biology and showing that stegosaurs were more morphologically
diverse than was previously realized. A new phylogeny, which includes all valid stegosaurian taxa, largely agrees with previous
studies and shows the European Dacentrurinae was sister taxon to Stegosaurus. Poor resolution at the base of Stegosauria is probably due to the fragmentary nature of many of the Chinese taxa. 相似文献
8.
简要回顾了我国山东省诸城市吕标乡库沟村龙骨涧晚白垩世早期辛格庄组中产出的巨型山东龙的研究历史,并讨论了巨型山东龙与"巨大诸城龙"的系统分类关系。对比两者的产出状况、骨骼结构和个体发育特征,作者认为两者为同物异名。依据古生物命名法规的优先律,巨型山东龙命名在先,合法有效;"巨大诸城龙"命名较晚,是一无效名称,应予取消。还讨论了巨型山东龙的生活习性和生态环境,认为巨型山东龙属陆栖性、群居性、植食性恐龙,生活在气候温暖、雨水充沛、植被繁茂的低山或丘陵地区。此外研究了巨型山东龙赋存地层的沉积特征,认为是一套辫状河流相或冲积扇相沉积,而不是湖相沉积。恐龙化石的密集产出是非正常集群死亡于突发性灾害事件的结果,而与国际上的K/T事件无关。 相似文献
9.
Nicholas R. Longrich 《Cretaceous Research》2011,32(3):264-276
At the end of the Cretaceous, 65.5 million years ago, the giant ceratopsids Triceratops and Torosaurus dominated North America’s dinosaur fauna. The origins of these giant ceratopsids, the Triceratopsini, are poorly understood. This paper describes Titanoceratops ouranos, a giant ceratopsid from the late Campanian (73-74 Ma) of New Mexico, and the earliest known triceratopsin. The holotype was previously interpreted as an aberrant and exceptionally large specimen of Pentaceratops sternbergi, but the animal does not show the diagnostic features of Pentaceratops. Instead, cladistic analysis shows that Titanoceratops is the sister taxon of a clade formed by Eotriceratops, Triceratops, and Torosaurus. With an estimated mass of 6.5 tons, Titanoceratops is among the largest dinosaurs known from the Campanian of North America, and rivaled Triceratops in size. The recognition of Titanoceratops suggests that giant chasmosaurines evolved once, among the Triceratopsini, and that the group evolved large size five million years earlier than previously thought. The giant horned dinosaurs probably originated in the southern part of the North American continent during the Campanian but only became widespread during the Maastrichtian. 相似文献
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11.
A new ornithopod dinosaur from the Upper Cretaceous (Maastrichtian) Snow Hill Island Formation, at James Ross Island, Antarctica is here described. This new taxon, named as Morrosaurus antarcticus gen. et sp. nov., is represented by a fragmentary right hind limb belonging to a medium-sized individual. Our phylogenetic analysis nests the new taxon in a monophyletic clade of Southern Hemisphere ornithopods that includes most Patagonian and Antarctic ornithopods. Several members of this group share a slender and bunched foot with narrow metatarsal IV, expanded chevrons, and bowed humerus without deltopectoral crest. Several features indicate that these ornithopods exhibit adaptations for a specialized cursorial mode of life. The recognition of Patagonian and Antarctic Ornithopoda belonging to a monophyletic clade reinforces palaeobiogeographical signals indicating that Patagonia, Antarctica and Australia shared a common Late Cretaceous terrestrial fauna. 相似文献
12.
A new ornithopod dinosaur from Antarctica, Trinisaura santamartaensis n. gen. et n. sp. is diagnosed by a unique combination of characters that includes a scapula with a spike-like acromial process with a strong and sharp lateral crest and longer than other ornithopods, a humerus with a rudimentary deltopectoral crest represented as a thickening on the anterolateral margin of the humerus, and shaft strongly bowed laterally, and an ischium gently curved along its entire length. The holotype specimen comprises vertebral and appendicular elements. The presence of axially elongate distal caudal vertebrae, pubis with long prepubic and postpubic processes, as well as a femur with a distinct anterior trochanter, pendant 4th trochanter and shallow anterior intercondylar groove constitute a combination of characters present in the Late Cretaceous Patagonian Gasparinisaura, Anabisetia and Talenkahuen. The materials were found on the surface enclosed in a hard sandstone concretion collected near the Santa Marta Cove, James Ross Island, from the lower levels of the Snow Hill Island Formation (Campanian). This is the first ornithopod taxon identified from this unit, and the second ornithischian dinosaur, after the ankylosaur Antarctopelta oliveroi. However, other ornithopod reports from nearby localities of James Ross and Vega islands in outcrops of the overlying Lopez de Bertodano Formation suggest that this clade was widely represented in the Campanian and Maastrichtian of the James Ross Basin, Antarctic continent. 相似文献
13.
R. A. B. Concepcion C. B. Dimalanta G. P. YumulJr D. V. Faustino-Eslava K. L. Queaño R. A. TamayoJr A. Imai 《International Journal of Earth Sciences》2012,101(1):273-290
Petrological and geochemical investigations of the sedimentary Lasala formation in northwest Mindoro, Philippines, offer new
insights into the origin of this geologically contentious region. Mindoro island’s position at the boundary between Sundaland
and the Philippine Mobile Belt has led to variable suggestions as to how much of it is continent derived or not. The Eocene
Lasala formation overlies the Jurassic Halcon metamorphics, a regionally metamorphosed suite generally thought to have formed
as a result of arc-continent collision processes. The sedimentary formation consists mainly of sandstones and shales interbedded
with mudstones, basalt flows, and subordinate limestones and conglomerates. Petrographic information on the Lasala clastic
rocks demonstrates a uniform framework composition that is predominantly quartzose. Major oxide, trace element abundances,
and various elemental ratios similarly impart a strongly felsic signature. These characteristics are taken to indicate a chiefly
continental, passive margin derivation and deposition of the Lasala sediments during the Eocene. The weak indication of active
margin influence is suggested to be an inherited signature, supported by paleogeographic models of the southeastern Asian
margin area during the pre-Cenozoic. 相似文献
14.
A well preserved skeleton of a new abelisaurid is reported here. The holotype of Viavenator exxoni was found in the outcrops of the Bajo de la Carpa Formation (Santonian, Upper Cretaceous), northwestern Patagonia, Argentina. This new taxon belongs to the South American clade of abelisaurids, the brachyrostrans. The current phylogenetic analysis places it as the basalmost member of a new clade of derived brachyrostrans, named Furileusauria, characterized by distinctive cranial, axial and appendicular anatomical features. The Santonian age of Viavenator allows filling the stratigraphic gap exhibited between the basal brachyrostrans of Cenomanian–Turonian age, and the derived forms from the Campanian-Maastrichtian. The evolution of abelisaurids during the Late Cretaceous, faunal replacements, and the adaptive radiation that occurred during that period of time in South America are discussed. 相似文献
15.
Megaraptoridae comprises a clade of enigmatic Gondwanan theropods with characteristic hypertrophied claws on the first and second manual digits. The majority of megaraptorids are known from South America, although a single genus (Australovenator) plus additional indeterminate material is also known from Australia. This clade has a controversial placement among theropods, and recently has been interpreted alternatively as a carcharodontosaurian or a tyrannosauroid lineage. We describe new fragmentary but associated postcranial remains from the opal fields of Lightning Ridge (middle-Albian, Griman Creek Formation) in north-central New South Wales. The new unnamed taxon exhibits a number of unusual features that suggest the presence of a hitherto unrecognised Australian megaraptorid. From an Australian perspective, the Lightning Ridge taxon predates Australovenator by ca. 10 Ma and is minimally coeval with megaraptoran material reported from the Eumeralla Formation of Victoria (but potentially 6.1–9.5 Ma younger). It is also notable as the largest predatory dinosaur yet identified from Australia and is only the second theropod known from more than a single element. A Bayesian phylogenetic approach integrating morphological, stratigraphic and palaeogeographic information tested both the carcharodontosaurian and tyrannosauroid placements for Megaraptora. Regardless of the preferred placement among Tetanurae, rigorous palaeobiogeographic analyses support an Asian origin of Megaraptora in the latest Jurassic (about 150–135 Ma), an Early Cretaceous (about 130–121 Ma) divergence of the Gondwanan lineage leading to Megaraptoridae, and an Australian root for megaraptorid radiation. These results indicate that Australia's Cretaceous dinosaur fauna did not comprise simply of immigrant taxa but was a source for complex two-way interchange between Australia–Antarctica–South America leading to the evolution of at least one group of apex predatory dinosaurs in Gondwana. 相似文献
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17.
E. Ja. Leven 《Stratigraphy and Geological Correlation》2010,18(3):290-297
As is argued in this work, genera Zarodella Sosnina, 1981, and Grovesella Davydov et Arefifard, 2007, could be ancestors of the genus Pamirina Leven, 1970, which gave birth to all higher fusulinids. Two former genera similar to each other are distinguished conventionally
to a certain extent in a large flexible taxon of small primitive polymorphic fusulinids close to the Bashkirian genera Eostaffella, Plectostaffella, and Semistaffella. Without essential changes, this taxon existed for a long time from the Bashkirian Age of the Late Carboniferous to the Bolorian
Age of the Permian. The genus Pamirina branched off that taxon in the Yakhtashian Age. Along with Zarodella and Grovesella, the genus Pamirina is attributed to the order Ozawainellida. 相似文献
18.
记述了产自山东诸城上白垩统王氏群中一个较完整的蜥脚类恐龙肱骨(ZJZ-57)。它具有一些进步特征,如肱骨三角胸嵴向远端扩展,肱骨近端外侧1/3处发育隆凸,表明其属于较进步的巨龙类成员。另外,它具有一些独特的鉴定特征组合区别于其他任何巨龙类:近端横向强烈扩展,近端最大宽度与骨干长度之比为0.55;骨干粗壮,粗壮指数为0.39。综合研究表明,ZJZ-57所属个体代表了一种新的巨龙类恐龙:臧家庄诸城巨龙(Zhuchengtitan zangjiazhuangensis gen.et sp.nov.),它可能与Opisthocoelicaudia的亲缘关系较接近。这是山东晚白垩世地层中首次发现的巨龙类恐龙。 相似文献
19.
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 hadrosaurines (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. 相似文献
20.
Geochemistry of the Caledonian basic volcanic rocks at the south margin of the Qinling orogenic belt, and its tectonic implications 总被引：1，自引：0，他引：1
The geochemistry of the basic volcanic rocks at the south margin of the Qinling orogenic belt(SMQOB) suggests that they were formed in an intraplate tectonic setting.The REE distribution patterns show these rocks are strongly enriched in LREE with high ∑REE, and their trace elements geochemistry is similar to that of contimental flood basalt.All the above evidence suggests that the Caledonian basic volcanic rocks in the SMQOB were tholeiitic basalts formed in an intraplate spreading-initial rift tectonic setting.The characteristics of regional geology and geochemistry indicate that there was an intraplate spreading-rift tectonic setting between the South Qingling block and the Yangtze block in the Caledonian epoch.The dynamic spreading in this district began in the Early Caledonian and then the intraplate spreadinginitial rifts were formed in the Late Caledonian.As a result of spreading of the Tethys and geodynamic processes in deep mantle ,the Mianlue-Huashan oceanic basin was formed between the Qinling block and the Yangtze block in Devonian,and the Qinling microplate was separated from the northern part of the Yangtze plate. 相似文献