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1.
We report on a new enantiornithine bird, Dunhuangia cuii, gen. et sp. nov., from the Lower Cretaceous Xiagou Formation of the Changma Basin, northwestern China. Although the material is incomplete, Dunhuangia cuii preserves unique coracoidal and sternal morphologies that distinguish it from other known enantiornithines; this specimen represents only the second enantiornithine reported from the Changma Basin that is diagnostic at the species level. This study enriches our understanding of the enantiornithine component of this ornithuromorph-dominated, Early Cretaceous avifauna. 相似文献
2.
Enantiornithine Bird with Diapsidian Skull and Its Dental Development in the Early Cretaceous in Liaoning, China 总被引：7，自引：5，他引：2
GONG Enpu HOU Lianhai WANG Lixia Department of Geology Northeastern University Shenyang Liaoning Institute of Vertebrate Paleontology Paleoanthropology Chinese Academy of Sciences Beijing Liaoning Department of Land Resources Shenyang Liaoning 《《地质学报》英文版》2004,78(1):1-7
A Iarge number of enantiornithine birds are discovered from the Early Cretaceous Jiufutang Formation in western Liaoning, China. They are all small-sized birds with a few small teeth. The enantiornithine bird from the Jiufutang Formation in the Shangheshou area, Chaoyang, Liaoning Province reported in this paper is the largest individual known in all enantiornithine birds of the Early Cretaceous. However, its teeth possess a feature of pseudoheterodont. Some different development stages of the new teeth substitute the earlier stages and the stages of development are preserved in this specimen. This development pattern is similar to that of Archaeopteryx and alligator but not dinosaur. A well-developed postorbital was also preserved in the skull, which was a diapsidian skull like that of Confuciusornis. Additionally, the distinctive preservation of its prefrontal distinguishes it from other enantiornithine birds of the Early Cretaceous. 相似文献
3.
描述发现于中国辽宁朝阳早白垩世九佛堂组地层中的一件鸟类标本。该标本体型较小,具有许多反鸟类的近裔特征。通过对新标本后肢形态特征的分析,可判断其为一小型树栖反鸟类。新标本具有发育的前肢和进步的乌喙骨,及发育滞后的后肢和相对原始的胸骨形态。胸骨长宽比约为1,顶端呈圆弧形,两个后侧突末端不膨大,中央突末端稍扩大,龙骨突基本不发育等。新标本同时具有反鸟类的原始和进步特征,以及原始的胸骨特征。其综合特征不同于已知任意一种小型反鸟类,因此建立一个反鸟类新属种——普通小反鸟(Microenantiornis vulgaris gen.et sp.nov.)。 相似文献
4.
A new Early Cretaceous enantiornithine bird from Liaoning Province of northeastern China, Shengjingornis yangi, gen. et sp. nov., is reported. This new bird possesses the following unique combination of features: a long rostrum, with some teeth in the front; short nasal; slender jugal; Y-shaped furcula, with expanded distal end of the hypocleidum; cake-like sternum, with a low and caudally distributed keel; strut-like and caudally concave coracoid. The derived features of the scapula and the wings suggest a powerful flapping flight capability. 相似文献
5.
The Coccondontoidea is a distinctive superfamily of pycnodont fishes characterized by a series of derived characters, including thick and well-ossified cranial bones supporting horns and spines and a hypertrophied pectoral girdle sutured to the skull forming a sort of cephalo-torax. A new distinctive coccodontoid species, Gladiopycnodus byrnei n. sp., is described from the Cenomanian locality of Hjoûla, Lebanon. This new species exhibits a unique combination of features that clearly support its inclusion within the coccodontoid family Gladiopycnodontidae, including an extremely elongate snout forming a sword-shaped rostrum, thick dermal bones ornamented with rounded tubercles, large supracleithrum and cleithrum extensively sutured to the skull, and irregularly imbricated scales covering the entire body. The new taxon differs from type species G. karami by having different meristic counts and body proportions, dermal bones strongly ornamentated, skull roof with partially fused bones, scales ornamented with small tubercles, and rounded scales covering the caudal peduncle absent. The presence of pectoral fins in our exquisitely well-preserved specimen allowed us to redefine the morphology of the genus Gladiopycnodus, also modifying the diagnosis of the family. In order to interpret the patterns of morphospace occupation and quantify the morphological diversification of pycnodonts through time, the geometric morphometric approach was used. The morphospace analysis revealed that a significant increase in morphological disparity of pycnodonts during the Late Cretaceous was related, at least in part, to the appearance of the representatives of the superfamily Coccodontoidea. The rapid evolutionary radiation of these well-armored pycnodonts was interpreted as an adaptive solution in response to the large predatory-prey escalation in the context of the Mesozoic Marine Revolution. 相似文献
6.
We present a large, fragmentary skull and the humerus of a mosasaur (Squamata, Mosasauroidea) recovered from upper Maastrichtian beds of the López de Bertodano Formation in Marambio (=Seymour) Island, Antarctica. The material belongs to a large, adult individual with marked heterodonty as well as unusual humeral features. Different phylogenetic analyses returned the studied specimen within the Tylosaurinae, while the distinctive features of the skull and humerus allow distinguish it from the unique Antarctic known tylosaurine species, Taniwhasaurus antarcticus (Novas et al., 2002), as well as from other known Late Cretaceous mosasaurids from the Southern Hemisphere, thus, justifying the erection of a new taxon, Kaikaifilu hervei gen. et. sp. nov. The different dental types documented in the specimen studied have been previously recorded through isolated teeth from the same locality and were subsequently referred to several genera. This new find is relevant for assessing the previously known fragmentary records of Antarctic mosasaurids, suggesting that its local diversity could be more reduced than previously interpreted. The new material represents the youngest occurrence of tylosaurines in Antarctica. 相似文献
7.
<正>A new dinosaur Chuxiongosaurus lufengensis gen.et sp.nov.is erected based on a nearly complete skull.The taxon is characterized by the lacrimal perpendicular to the ventral margin of the upper jaw,which is similar to that of Thecodontosaurus;a depression present on the dorsal profile of the snout behind the naris;the rostral profile of the maxilla slopes continuously towards the rostral tip;and the presence of 25 dentary teeth.It also displays prosauropod characters such as a relatively long skull,the slope of the maxillary rostral profile,and teeth that do not have basically constricted crowns.The new specimen is more basal than Anchisaurus and represents the first basal sauropod dinosaur from the Early Jurassic of China. 相似文献
8.
Pachycephalosaurs, a group of ornithischian dinosaurs with distinctive cranial ornamentation and skull domes, underwent dramatic changes in cranial morphology during ontogeny. This has caused debate about whether some specimens belong to juveniles or adults, which impacts studies of pachycephalosaur phylogeny and evolution. One such debate concerns a small skull roof specimen from the Campanian (Upper Cretaceous) of New Mexico, NMMNH P-33898, which was originally described as an indeterminate juvenile but later regarded as a mature adult and erected as the holotype of a new small-bodied species, Stegoceras novomexicanum. We restudied NMMNH P-33898 using computed tomography scanning, morphometric and phylogenetic analyses, and comparisons to growth series of other pachycephalosaurs (Stegoceras validum, Pachycephalosaurus wyomingensis). We conclude that two purported paratype specimens of Stegoceras novomexicanum cannot be referred to the same taxon as the holotype, that the holotype and controversial paratypes all belong to immature specimens and not aberrant small-bodied adults, but that current evidence cannot clearly determine whether NMMNH P-33898 is a juvenile belonging to its own diagnostic species (S. novomexicanum) or is a juvenile of Stegoceras validum, Sphaerotholus goodwini, or another known taxon. We review the pachycephalosaur record of New Mexico and demonstrate that pachycephalosaurs were important components of dinosaur faunas in the southern part of Western North America during the ∼15 million years before the end-Cretaceous extinction, just as they were in roughly contemporaneous northern localities. 相似文献
9.
Rebbachisauridae is a poorly understood clade of diplodocoid sauropod dinosaurs, currently known only from the Cretaceous of Africa, Europe and South America. European representatives are particularly rare and fragmentary. Here, we report an anterior caudal vertebra from the Barremian (Early Cretaceous) Wessex Formation of the Isle of Wight, off the southern coast of England. This specimen possesses several features known only in rebbachisaurids and shares two synapomorphies with the Afro-European taxa Demandasaurus darwini and Nigersaurus taqueti, both pertaining to the morphology of the neural spine. These features are the development of triangular lateral processes and the presence of an elliptical fossa on the lateral surface, bounded by the lateral lamina and postspinal rugosity. The Isle of Wight specimen also shares several features solely with Demandasaurus, indicating a close relationship with the Spanish taxon. These include the presence of a hyposphenal ridge, as well as an anteriorly excavated caudal rib that is restricted almost entirely to the neural arch. However, it differs from Demandasaurus in a number of ways, including the lack of excavation on the posterior surface of the caudal rib, the orientation of the neural spine, and the composition and morphology of the lateral lamina. In addition, the Isle of Wight vertebra possesses one potential autapomorphy: bifurcation of the elliptical fossa on the neural spine. However, because of the fragmentary nature of the material, a new name is not erected. Along with Demandasaurus and Histriasaurus boscarollii, this caudal vertebra indicates the presence of at least three European rebbachisaurid taxa and provides new anatomical information on this enigmatic clade of sauropod dinosaurs. 相似文献
10.
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
11.
Two New“Notostracans”,Chenops gen.nov.and Jeholops gen.nov. (Crustacea:Branchiopoda:?Notostraca) from the Yixian Formation,Northeastern China 总被引：1，自引：1，他引：0
<正>The Early Cretaceous Jehol biota of northeastern China contains a diverse group of notostracans, including two genera,Chenops and Jeholops,described here.Chenops is characterized by a combination of an ovate carapace,narrow anal plate,equant distal endites and endopod on the anterior thoracic limbs.In addition to the new species,Chenops yixianensis,the genus also provisionally includes Prolepidurus oblongus Oleynikov, 1968.Jeholops,however,is monotypic,represented by the new species Jeholops hongi.It is characterized by a combination of kazacharthran and notostracan features unique to this taxon.Both new genera are provisionally placed in the taxon Notostraca.More detailed work exploring the morphology of exceptionally-preserved branchiopod crustaceans is needed.The difficulties in placing fossil notostracans into a phylogenetic framework are discussed. 相似文献
12.
We review the previously described Late Cretaceous (Santonian) bird remains from the Csehbánya Formation in the Bakony Mountains of Hungary, augmenting initial work by Ősi ( 2008 ), and add a number of newly collected fossils. All together, the eight fossil specimens so far collected from this site are important to our understanding of avian evolution because they document a large range of taxon body sizes from at least one major lineage (Enantiornithes) and come from a critically undersampled time period in the Cretaceous. Globally, very little fossil bird material has been collected from the middle stages of the Late Cretaceous, the Coniacian and Santonian; most known taxa are either Early Cretaceous (ca. 120 Ma) in age or are from the terminal Campanian and Maastrichtian (ca. 70–65 Ma). Indeed, one of the Csehbánya Formation fossil birds is recognized as a new taxon of large enantiornithine, an avisaurid apparently similar in its largely unfused foot morphology to the Argentine Soroavisaurus and to the North American Avisaurus. The Central European records reviewed in this paper highlight the wide distribution of some Late Cretaceous fossil birds, particularly avisaurid enantiornithines, and lead us to a brief discussion of avian biogeography at the end of the Mesozoic. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
13.
Shansisuchus shansisuchus Young,1964 was restudied on the basis of a new specimen.Some anatomical features that were either briefly or not described at all in the original study were detailed.The new specimen not only provides further information on the skull anatomy and the vertebral column but also expands the range of the geographical distribution of the taxon.With new information,the diagnosis of S.shansisuchus was emended and its phylogenetic relationships were further analyzed.S.shansisuchus differs from other archosauriforms primarily in the presence of a large subnarial fenestra anterior to the antorbital fenestra,tongue-in-groove articulations between the ascending process of the premaxilla and nasal and between the premaxilla and maxilla,a tall and posterodorsally directed ascending process of the maxilla,a knee-shaped process of the postorbital projecting into the orbit,a broad descending process of squamosal distally well forked and a large,deeply bow-shaped intercentrum tightly anchoring/capping the sharp ventral edges of two neighboring centra together in cervical and at least first eight dorsal vertebrae.With additional information derived from the new specimen,the phylogenetic relationships of S.shansisuchus were reanalyzed;it is closely related to Erythrosuchus-Vjushkovia clade. 相似文献
14.
The Early Cretaceous lizard Yabeinosaurus was one of the first taxa described from the now famous Jehol Biota of northeast China. Misinterpreted for more than 60 years and misclassified as a gekkotan based on juvenile specimens, it is now recognised to be a large, well-ossified lizard with an extended period of skeletal maturation. Here we describe two additional complete specimens of Yabeinosaurus that provide new information on skeletal morphology, most notably of the skull, pectoral girdle, and tail. Both specimens also preserve gut contents, showing that large individuals took vertebrate prey, including fish. A more complete understanding of Yabeinosaurus permits a review of the type specimen of Yabeinosaurus youngi. Skull traits used to distinguish Y. youngi from Yabeinosaurus tenuis are invalid but, as noted by Hoffstetter, the two species differ markedly in limb proportions. Attribution of Young’s specimen to Yabeinosaurus is equivocal, but could potentially extend the temporal range of the lineage into the Jurassic. A new phylogenetic analysis based on a morphological data set places Yabeinosaurus on the stem of Scleroglossa, as the sister taxon of the contemporaneous Japanese lizard Sakurasaurus. 相似文献
15.
Thomas Lehmann Patrick Vignaud Hassane Taïsso Mackaye Michel Brunet 《Journal of African Earth Sciences》2004,40(5):201
The Mission Paléoanthropologique Franco-Tchadienne (MPFT) found a new species of Orycteropodidae (Mammalia, Tubulidentata) in the Kollé fossiliferous sector, northern Chad. After Orycteropus abundulafus [Journal of Vertebrate Paleontology 20 (1) (2000) 205–209; Lehmann, T., Vignaud, P., Likius A., Brunet M., in press. A new Orycteropodidae (Mammalia, Tubulidentata) in the Mio-Pliocene of Northern Chad. Zool. J. Linnean Soc.], this specimen is the second complete skeleton of fossil aardvark found in the Djurab desert. It is the first complete representative of an Orycteropus species found in the Pliocene of Africa. In regard to the Miocene fossil aardvarks, this new taxon, Orycteropus djourabensis nov. sp., shows more affinities with the extant O. afer. The main differences are the larger teeth and the shorter hand in the fossil form. Kossom Bougoudi and Kollé represent a chronological series that gives a unique opportunity for studying the evolution of the African Tubulidentata around the Mio-Pliocene boundary (5.5-4 My). The new species is distinct from the older Chadian Orycteropodid from KB and it embodies the taxonomic turnover that took place within the order Tubulidentata around this boundary in Africa. Moreover, this new species is the oldest known Orycteropus species that clearly belongs to the modern forms including the extant aardvark. 相似文献
16.
A new specimen discovered from the Falang Formation in northeastern Yunnan represents the most complete skeleton of Triassic pistosauroids. The new specimen is referred to Yunguisaurus Cheng et al., 2006 on the basis of the skull features, such as the presence of a separated nasal entering the external naris, a large pineal foramen located at the frontal/parietal suture and an interpterygoid vacuity with a narrow anterior extension. The new specimen differs from the type species of Yunguisaurus liae Cheng et al., 2006 in some aspects. Most of these differences can be attributed to ontogenetic variations. The new specimen is provisionally considered as Yunguisaurus cf. liae although its relatively short snout of the skull and slenderer hyoid may not be explained ontogenetically. Whether or not the new specimen represents a different taxon has to wait for a detailed study of the whole skeleton. 相似文献
17.
A new bird from the early Cretaceous Yixian Formation of Liaoning, China is described. This new species, Grabauornis lingyuanensis, shares several synapomorphies with the Enantiornithes. The specimen is relatively well preserved. The skeletal morphology of Grabauornis bears close resemblance to that of other Chinese members of this clade. The brachial index （the ratio between the lengths of humerus and ulna） is 0.95, which is close to the average for enantiornithine birds. It indicates that Grabauornis was a rather good flyer, and the presence of an alula in the wing further testifies to this. 相似文献
18.
Burmese amber has recently provided some detailed glimpses of plumage, soft tissues, and osteology of juvenile enantiornithine birds, but these insights have been restricted to isolated wing apices. Here we describe nearly half of a hatchling individual, based on osteological and soft tissue data obtained from the skull, neck, feet, and wing, and identified as a member of the extinct avian clade Enantiornithes. Preserved soft tissue provides the unique opportunity to observe the external opening of the ear, the eyelid, and fine details of tarsal scutellation. The new amber specimen yields the most complete view of hatchling plumage and integument yet to be recovered from the Cretaceous, including details of pterylosis, feather microstructure, and pigmentation patterns. The hatchling was encapsulated during the earliest stages of its feather production, providing a point for comparisons to other forms of body fossils, as well as isolated feathers found in Cretaceous ambers. The plumage preserves an unusual combination of precocial and altricial features unlike any living hatchling bird, having functional remiges combined with sparse body feathers. Unusual feather morphotypes on the legs, feet, and tail suggest that first generation feathers in the Enantiornithes may have been much more like contour feathers than the natal down observed in many modern birds. However, these regions also preserve filamentous feathers that appear comparable to the protofeathers observed in more primitive theropods. Overall, the new specimen brings a new level of detail to our understanding of the anatomy of the juvenile stages of the most species-rich clade of pre-modern birds and contributes to mounting data that enantiornithine development drastically differed from that of Neornithes. 相似文献
19.
A second species of the extinct scydmaenine genus Cretoleptochromus Cai & Huang, C. burmiticus sp. nov., is described and figured based on three exquisitely preserved specimens embedded in mid-Cretaceous Burmese amber. The new taxon possesses an extremely elongate body form and strongly extended legs and antennae that provide reliable means for species diagnosis and a ready separation from the only known congener, the type species C. archaicus Cai & Huang, also reported from Burmese amber. The morphology of C. burmiticus also suggests that this species was probably an active diurnal predator living in open environments. 相似文献
20.
Mongolian Paleontological Center (MPC) 100/1305 is one of the most complete ankylosaurid skeletons ever collected, and includes much of the postcranial skeleton and numerous in situ osteoderms. This specimen has been referred to Saichania chulsanensis, based on the similarity of the skull compared to the holotype of Saichania, MPC 100/151. However, MPC 100/1305 does not include a skull, and so referral of MPC 100/1305 to Saichania must be based on postcranial characters. Comparison of the postcrania of MPC 100/1305 and MPC 100/151 reveals several differences in the scapula, humerus, and metacarpals, indicating that MPC 100/1305 should not be referred to Saichania. Additionally, although it was previously reported that MPC 100/1305 was collected from the Baruungoyot Formation at Khulsan in Mongolia, collection records indicate that this specimen was instead collected from the Djadokhta Formation at Zamyn Khond. Two ankylosaurid species are known from the Djadokhta Formation of Mongolia and China, Pinacosaurus grangeri and P. mephistocephalus. There are no diagnostic characters in MPC 100/1305 that can be used to refer this specimen to P. grangeri or P. mephistocephalus, and there are a few differences between MPC 100/1305 and Pinacosaurus, such as the number of caudal vertebrae, and morphology of the coracoid, which have uncertain taxonomic implications. At present, MPC 100/1305 is best referred to Ankylosauridae indet., or cf. Pinacosaurus, based on its generally congruent morphology with Pinacosaurus and its provenance from the Djadokhta Formation, in which Pinacosaurus is the only recognized ankylosaurid taxon. 相似文献