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1.
Abstract: A new oviraptorid is described on the basis of a partial forelimb collected from the Upper Cretaceous redbeds of Bayan Mandahu, Inner Mongolia. Machairasaurus leptonychus, gen. et sp. nov. is diagnosed by slender, weakly curved manual unguals, reduced flexor tubercles, penultimate phalanges that are subequal in length to the preceding phalanges, and short, robust manual digits. Machairasaurus is found to be a member of the Ingeniinae, along with Ingenia yanshini, Heyuannia huangi, Conchoraptor gracilis, and Nemegtomaia barsboldi. Machairasaurus exhibits unusual proportions of the manus, suggesting that the manus was not primarily used to grasp prey. Instead, Machairasaurus and other oviraptorids are likely to have fed largely on plant material. The recognition of a previously unknown oviraptorid at Bayan Mandahu provides further evidence that the Bayan Mandahu dinosaur assemblage is distinct from that found at the Djadokhta Formation exposures at Bayn Dzak, Tugriken Shireh, and Ukhaa Tolgod. Given that these localities are separated by just a few hundred kilometres and represent similar palaeoenvironments, marked differences in the fauna suggest that the Bayan Mandahu Formation of Inner Mongolia is not coeval with the known Djadokhta localities in Mongolia.  相似文献   

2.
The discovery of a new ankylosaurid skull with some unusual features from the Baruungoyot Formation of Mongolia prompted a systematic review of ankylosaurid specimens from the Baruungoyot and Nemegt formations. Dyoplosaurus giganteus was found to possess no diagnostic features and is regarded as a nomen dubium. The holotype of Tarchia kielanae (previously synonymized with Tarchia gigantea) has one autapomorphy, an accessory postorbital ossification with surrounding furrow, and Tar. kielanae is here considered a valid species, making the combination Tar. gigantea unnecessary. An accessory postorbital ossification is also found in the holotype of Minotaurasaurus ramachandrani, and this species is here considered a junior synonym of Tar. kielanae. The newly described skull from the Baruungoyot Formation forms the holotype of a new genus and species, Z araapelta nomadis gen. et sp. nov. , diagnosed by unusual bilayered ornamentation on the squamosal horn and extensive postocular ornamentation. Two distinct tail club handle morphotypes are present in the Nemegt Formation and probably represent two different species. However, it is impossible to assign either tail club morphotype to the single valid species from the formation, Saichania chulsanensis, because of a lack of overlapping material. A revised phylogenetic analysis including newly identified characters found Zaraapelta nomadis to be most closely related to Tar. kielanae. © 2014 The Linnean Society of London  相似文献   

3.
Enantiornithes is the most speciose clade of Cretaceous birds, but many taxa are known from isolated postcranial skeletons. Two embryonic enantiornithine bird skeletons of Gobipipus reshetovi gen. et sp. nov. from the Upper Cretaceous (Campanian) Barun Goyot Formation of the Gobi Desert in Mongolia provide new insights into the anatomy, radiation, and mode of development of early avialans. In recent times, both enantiornithine and ornithuromorph birds are known from the Barun Goyot Formation as well as from the Djadokhta and Nemegt Formations. The 80-million-year-old Gobipipus skeletons encased within eggshells shows several features characteristic of enantiornithine birds. The wing skeleton and shoulder girdle show morphological features indicating that Gobipipus achieved sophisticated powered flight. Gobipipus reshetovi gen. et sp. nov. is quite distinct from the sympatric enantiornithine species Gobipteryx minuta from the same strata in many anatomical features. Phylogenetic analysis of 26 avialan ingroup taxa based on distribution of 202 characters indicate that Gobipipus is a basal member of enantiornithine birds along with Confuciusornis and shares more characters with ornithuromorphs than previously recognized. The embryonic nature of Gobipipus specimens sheds new light on the developmental history of enantiornithine birds. The well-ossified bones of the fore- and hind limbs, and fusion of many skeletal elements indicate a precocial mode of development in Gobipipus. Apparently Gobipipus hatchlings could walk away from the ground nests as soon as they emerged from their eggs. The asymmetry of egg poles are unique features of Gobipipus eggs (oogenus Gobioolithus) among Cretaceous avialans. The microstructure of the shell in Gobioolithus eggs with the embryos of Gobipipus is typical avian (of ornithoid basic type) and less ratite-like in morphology of the spongy layer than is that in the other possible egg-remains of enantiornitine birds (oofamily Laevisoolithidae).  相似文献   

4.
A new dinosaur, Ceratonykus oculatus gen. et sp. nov. (Parvicursoridae, Alvarezsauria), from the Upper Cretaceous (Baruungoyot Formation) of Mongolia is described based on a fragmentary skeleton. It differs from other alvarezsaurians in many characters, including the short femora, long tarsometatarsals, and considerably reduced third metatarsals. The carpometacarpals contain spikelike bones. The natural endocast of the new taxon shows large acoustic tubercles, the ventral position of the optic lobes in the midbrain, and the absence of a vertical flexure at the brain floor. The data obtained cast doubt on the taxonomic position of alvarezsaurians in the Theropoda.  相似文献   

5.
A new oviraptorosaur Nankangia jiangxiensis gen. et sp. nov. is described on the basis of a partial postcranial skeleton with a partial lower jaw collected from the Upper Cretaceous Nanxiong Formation of Ganzhou, in Jiangxi Province of southern China. The new taxon is diagnosed by: (1) a mandibular symphysis that is not turned down; (2) neural spines of the cranial caudal vertebrae that are wider transversely than anteroposteriorly, forming a large posterior fossa with rugose central areas; (3) a femoral neck extending at an angle of about 90 to the shaft; and (4) a ratio of femur to tibia length of 0.95. Phylogenetic analysis recovers Nankangia as basal to the oviraptorid Yulong, but more derived than Caenagnathus, which also has a mandibular symphysis that is not turned down. The coexistence of Nankangia jiangxiensis, Ganzhousaurus nankangensis, Jiangxisaurus ganzhouensis, an unnamed oviraptorid from Nanxiong Basin and Banji long suggests that they occupied distinct ecological niches. Nankangia may have been more herbivorous than carnivorous.  相似文献   

6.
河南内乡桑坪组一新禽龙及其地层学意义   总被引:6,自引:0,他引:6  
记述了禽龙亚目(Iguanodontia)一个新属种─—诸葛南阳龙(Nanyangosaurus zhugeii)。标本产于河南内乡夏馆镇桑坪组的紫红色泥质粉砂岩中。它的自近裔特征包括:第二掌骨超过第三掌骨和第四掌骨长度的90%;第四掌骨远端异常粗壮;指节IV-1长度小于远端横向宽度;第二跖骨近端腹背向长度大于第三跖骨。系统发育分析表明,南阳龙代表亲缘关系与鸭嘴龙超科最为接近的一类鸟脚类恐龙。诸葛南阳龙的发现支持了夏馆盆地红层为早白垩世沉积的观点。  相似文献   

7.
A new horned dinosaur, Gobiceratops minutus gen. et sp. nov. (Bagaceratopidae, Neoceratopsia), from the Upper Cretaceous Baruungoyot Formation of the Khermin Tsav locality (southern Mongolia) is described based on a 3.5-cm-long skull. The nasal included in the orbital border suggests relationship between the new taxon and Bagaceratops rozdestvenskyi. It is proposed that, unlike other neoceratopsian families, the family Bagaceratopidae is of Paleoasiatic origin.  相似文献   

8.
记述了一件发现于内蒙古临河巴彦满达呼上白垩统乌兰苏海组的窃蛋龙科新材料并建立了一新属新种——戈壁乌拉特龙(Wulatelong gobiensis gen. et sp. nov.)。新属种具有以下不同于其他窃蛋龙科成员的独特特征:外鼻孔大而细长,腹端低于前上颌骨中部;上颌骨的颧骨支呈带状,并向后延伸至眶前隔之后,叠覆于颧骨外侧面;外侧视,上隅骨的前背突基部收缩。戈壁乌拉特龙具有一些其他窃蛋龙科成员不具有的近祖特征,而与更原始的窃蛋龙类接近,说明戈壁乌拉特龙代表了窃蛋龙科中一个相对原始的属种。这些近祖特征包括:下颞颥孔的背缘较窄,泪骨的前突和后突相对较长,外翼骨和外下颌孔的位置都相对靠后,肩胛骨短而纤细,肠骨的耻骨茎较坐骨茎向腹侧延伸更长并前后向更宽,坐骨较短,以及第三跖骨近端侧扁等。因此戈壁乌拉特龙的系统发育位置可能居于原始窃蛋龙类和其他窃蛋龙科成员之间。对巴彦满达呼恐龙动物群的初步分析支持巴彦满达呼红层代表了蒙古高原戈壁地区上白垩统红层中的最早沉积层位的结论。  相似文献   

9.
Abstract: Two new genera with six new species of hangingflies (Mecoptera: Raptipedia: Cimbrophlebiidae) are described. They were collected from the Middle Jurassic nonmarine sedimentary strata of the Jiulongshan Formation in Daohugou, Inner Mongolia, north‐eastern China. This report of Cimbrophlebiidae from the Yanliao Biota provides detailed morphological information and evidence of a broad diversity of Cimbrophlebiidae during the Middle Jurassic. A key to the known species of Cimbrophlebiidae is provided.  相似文献   

10.
The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs.  相似文献   

11.
Abstract: A new genus and species of basal non‐Viverravidae Carnivoramorpha, Dawsonicyon isami, is named and described. This new taxon is based upon DMNH 19585, an almost complete skeleton, which was collected from the Black’s Fork Member (informal ‘Bridger B’ subunit) of the Bridger Formation in southwestern Wyoming, USA. The specimen is incorporated into an existing craniodental data matrix, and the associated phylogenetic analyses support the identification of this species as a new basal carnivoramorphan. This new taxon is dentally compared to all known genera of non‐viverravid basal carnivoramorphans, as well as with all known species of the problematic genus Miacis. Postcrania are compared in detail with other described specimens of non‐viverravid basal carnivoramorphans and more generally with known postcrania of viverravids. Preliminary functional interpretations of a scansorial locomotor mode are offered for this new taxon. Its implications for the diversity of middle Eocene basal carnivoramorphans is briefly discussed, including expansion of the already high diversity in the Black’s Fork Member of the Bridger Formation (at least 11 species in 8 genera).  相似文献   

12.
A new genus and species of Nanhsiungchelyidae (Testudines: Cryptodira), Yuchelys nanyangensis n. g. n. sp., are described on the basis of a partial skeleton from the Late Cretaceous Gaogou Formation of Neixiang, Nanyang Basin, Henan Province. It is the first nanhsiungchelyid record in the east-central part of China and fills the geographical gap between the western (Uzbekistan, Mongolia, Northern and Southern China) and eastern (Japan) distribution areas of the family Nanhsiungchelyidae.  相似文献   

13.
根据可能发现于江西赣州晚白垩世南雄组地层中一件标本报道了窃蛋龙科一新属种——斑嵴龙。新标本具有以下不同于其他窃蛋龙属种的特征:由前颌骨和鼻骨形成的脊冠具有阶梯状的后端,表面有两个纵向的沟槽和许多倾斜的条痕;外鼻孔延长,其后侧与眶骨相近;翼骨腭骨支背缘有一深窝;齿骨后背缘有纵向沟槽;上隅骨前背缘有小结节。斑嵴龙腭部和下颌的一些特征不同于窃蛋龙科的其他属种,但近似于更原始的窃蛋龙类。这些特征表明斑嵴龙代表窃蛋龙科中相对原始的一个属种。这一系统发育假说得到了定量的系统发育分析的支持。斑嵴龙的发现不仅增加了晚白垩世窃蛋龙科的分异度,而且为这一类群的特征演化提供了重要信息。  相似文献   

14.
The fossil record of metriorhynchids and plesiosaurians from the Rosso Ammonitico Veronese Formation (RAVFm, Middle–Upper Jurassic, Italy) is represented by elements collected between the eighteenth and twentieth centuries. All the metriorhynchid material is referred to the genus Neptunidraco. The first RAVFm plesiosaurian material was collected in the nineteenth century and referred to Plesiosaurus: elements are here described and interpreted as a chimerical association of crocodylomorph and plesiosaurian bones, providing the first co-occurrence of these clades in the RAVFm. The second plesiosaurian is the associated skeleton that we refer to Anguanax zignoi gen. et sp. nov. Bayesian phylogenetic analysis confirms the basal geosaurine affinities of Neptunidraco resulted by parsimony analysis. Using both methods, Anguanax was recovered as a basal pliosaurid, sister group of the clade including Marmornectes and Thalassophonea. Bayesian inference methods indicate that both Italian lineages diverged from other known lineages between 176 and 171 Mya, also showing divergence rates significantly higher than any other representative of their respective clades. We suggest a phase of rapid evolutionary adaptation to deeper marine environments in the ancestors of the Rosso Ammonitico Veronese reptiles as a response to the latest Liassic regressive regime in Northern Tethys.  相似文献   

15.
A LATE MESOZOIC BIRD FROM INNER MONGOLIA   总被引:4,自引:0,他引:4  
Otogornisgenghisigen.etsp.nov.HolotypePectoralgirdleandwingelements.(IVPPV96O7)HorizonandLocalityYijinhoIuoFormation(EarlyCretaceous);Chaibu-Sumi,otog-qi,Yikezhao-meng,InnerMongolia.DiagnosisAmedium-sizedbird.Longbonesthick-waIled.Acromionofscapulaprotrudingforward.Coracoidwithexpandedheadandbroadp1ate-shapeddistalend.Humerusrelativelystrongandshorterthanradiusandulna,pneumaticfossaabsent,capitalgrooveprominent,deltoidcrestnotdeve1oped,olecrana1fossasha1low,su1cusform.scapu1otricipit…  相似文献   

16.
近几十年,华北的二马营组上部地层以产出中国肯氏兽-山西鳄四足动物化石组合而闻名.最近在山西临县白道峪于上覆的铜川组一段发现了中国肯氏兽.本文描述了同一地点同一层位产出的主龙型类化石,包括一具山西鳄的部分骨架以及一些可以归入suchian的主龙类.它们是铜川组一段首次记述的主龙型类.最有鉴定特征的suchian材料包括一个大的髂骨以及一个小的、形状很奇特的、可能是跟骨的骨骼.髂骨可能可以归入一个奇异的波波龙类(poposauroid).因为中国肯氏兽与山西鳄同时出现在白道峪,表明中国肯氏兽-山西鳄组合可以向上延伸到铜川组一段.髂骨与跟骨大小悬殊,可能代表两个从未在中国肯氏兽-山西鳄组合报道过的物种.白道峪发现了特化的波波龙类,支持了波波龙类在中三叠世大量分化的观点.  相似文献   

17.
The Moenkopi Formation has yielded partial and isolated remains of important archosaurs including rauisuchian skull fragments and isolated poposaur centra and pelvic girdle elements. A recently discovered skeleton referable to Arizonasaurus babbitti shows that most of these archosaurian remains belong to one taxon. Characteristics of the skeleton of Arizonasaurus show that it belongs to a poorly known group of Middle Triassic (240-230 Myr ago) archosaurs called the ctenosauriscids, and that ctenosauriscids are or are closely related to poposaurs. Furthermore, many characteristics of Arizonasaurus provide evidence that poposaurids and ctenosauriscids are derived rauisuchians. The presence of a poposaurid in the early Middle Triassic suggests that the divergence of birds and crocodiles occurred earlier than previously thought. Middle Triassic ctenosauriscids also allow the correlation of Triassic faunas in Europe, Asia, North America and Africa. The Moenkopi Formation fauna represents a transitional fauna between Early and Late Triassic faunas.  相似文献   

18.
Placoderms, representing phylogenetically more inclusive jawed vertebrates and successive sister taxa to crown‐group gnathostomes, are critical to our understanding of character evolution within the crown‐group (chondrichthyans + osteichthyans), including developmental characters. Early ontogenetic stages of placoderms are generally poorly known, although some exceptional faunas preserve both embryonic (e.g. from the Gogo Formation, Western Australia) and post‐embryonic individuals (the Miguasha Formation, Canada; Lode Formation, Latvia; Merriganowry Formation, Gogo Formation, Australia). Information provided by these ontogenies is relevant to questions of placoderm taxonomy and phylogeny, but also to broader questions pertinent to vertebrate evolution as a whole, for example, evolution of bone development, evolution of the axial skeleton and evolution of reproduction.  相似文献   

19.
We describe an exceptionally well-preserved partial skeleton of a new bird from the early Eocene Fur Formation of Denmark. Like other fossils from these marine deposits, the partial skeleton is three-dimensionally preserved and articulated. This new Danish specimen consists of a skull, vertebral column, ribs, pelvis, and hindlimbs. Concerning characters of the pelvis, tibiotarsus and tarsometatarsus, the new fossil bears morphological affinities to charadriiform birds (shorebirds and relatives). A phylogenetic analysis of higher neomithine (modern birds) taxa also supports a close relationship between the new specimen and modern Charadriiformes. The morphologies of the skull and vertebrae, however, distinguish the new fossil from all recent charadriiform families.  相似文献   

20.
Recent survey of the fossiliferous variegated mudstones of the PK1 locality (Sabapondaung) in the late middle Eocene Pondaung Formation (central Myanmar) has led to the recovery of a partial right innominate of a relatively large-bodied primate. Given its size and provenance, this bone probably belongs to the same individual represented by the NMMP 20 primate partial skeleton described previously from the same locality. The new fossil, which preserves the region around the acetabulum and the adjacent part of the ilium, clearly exhibits strepsirrhine rather than anthropoid affinities. This addition to our knowledge of the NMMP 20 partial skeleton allows us to reassess the different locomotor interpretations that have been proposed for this specimen. Aspects of pelvic morphology suggest that the NMMP 20 partial skeleton documents a primate that probably engaged in active arboreal quadrupedalism similar to that practiced by medium-sized Malagasy lemurids rather than lorislike slow moving and climbing. Given the conflicting phylogenetic signals provided by NMMP 39 (a talus showing anthropoid affinities) and NMMP 20 (a partial skeleton bearing adapiform affinities), it appears that two higher-level taxonomic groups of relatively large-bodied primates are documented in the Pondaung Formation. The recent discovery of two taxa of sivaladapid adapiforms from the Pondaung Formation indicates that the assumption that the NMMP 20 partial skeleton belongs to an amphipithecid can no longer be sustained. Instead, this specimen apparently documents a third large-bodied sivaladapid species in the Pondaung Formation.  相似文献   

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