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Cervical vertebrae of azhdarchid pterosaurs were discovered in two Upper Cretaceous (Baynshire Suite) dinosaur localities, Bayshin Tsav and Burkhant, in the Gobi Desert. These are the first discoveries of pterosaur remains in the Upper Cretaceous of Mongolia. The Burkhant specimen includes a nearly complete atlas−axis complex, which has rarely been described in this clade of pterosaurs. Although all elements comprising this complex are fused together, a wing−like atlas neural arch is still discernable. The postzygapophyseal facet of the axis is long anteroposteriorly and convex dorsally, and would likely have allowed a fairly large range of dorsoventral flexion at the axis−third cervical joint unlike in other well−known ornithocheiroids such as Pteranodon and Anhanguera. Both Mongolian localities represent inland, terrestrial environments, which were apparently not typical habitats of pterosaurs, thus adding further evidence for the ubiquity of Azhdarchidae during the Late Cretaceous.
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A new tritylodontid synapsid from Mongolia

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The Upper Jurassic Ulaan Malgait Beds in the Shar Teg locality of southwestern Mongolia have yielded remains of a new tritylodontid therapsid (Synapsida), Bienotheroides shartegensis sp. nov. The specimen consists of a fragmentary skull associated with lower jaws. It is assigned to Bienotheroides based on its short snout, a premaxilla−palatine contact, very reduced maxilla, relatively rounded corner of upper postcanine teeth (PC), and PC cusp formula of 2−3−3. It differs from the other species of Bienotheroides in having a much more reduced middle mesial cusp of PC. It further differs from B. zigongensis and B. ultimus in having shorter and wider PC, from B. ultimus in lacking a projection at the middle mesial margin of PC, and from B. wansienensis in lacking the vestigialmost mesiobuccal cusp of PC and in lacking a diastema between upper I1 and I2. This is the first discovery of the Tritylodontidae in Mongolia. This discovery extends the taxonomic (morphological) diversity and geographic range of Bienotheroides and underlies the success of the genus in the Middle to Late Jurassic biota of eastern Eurasia.
Although the distribution of Asian crocodyliforms was extended northwards during the Paleocene–Eocene greenhouse world, the fossil record in northern Asia becomes scarce towards the end of the Eocene. We here report the first crocodyliform (an isolated tooth) from the upper Eocene Ergilin Dzo Formation of southeastern Mongolia, the mammalian fauna of which defines the Ergilian Asian Land Mammal Age. The conical non-recurved crown, the near complete root with the central resorption facet, and its late Eocene age suggest the crocodyliform affinity of the tooth. The current finding represents one of the northernmost occurrences of crocodyliforms in the upper Eocene of Asia (paleolatitude ca. 49°30’ N), and demonstrates that SE Mongolia probably met thermal requirements of crocodyliforms during the late Eocene.
A description of Nomingia gobiensis gen. et sp. n., the first known dinosaur with a pygostyle, the structure known so far only in birds, is presented. The specimen comes from the Late Cretaceous strata at Bugin Tsav, Trans-Altai Gobi, Mongolia. N. gobiensis is assigned within the Oviraptorosauria based on the following characters: pneumatized caudal vertebrae, posteriorly concave ischium, and deep cervicodorsal hypapophyses. This specimen has been previously partially described without being formally named (Barsbold et al. 2000).
Khurendukhosaurus is an enigmatic genus of choristodere, recorded from the Lower Cretaceous of East Asia, Mongolia, and Siberian Russia. Until now, it was known only from isolated skull and postcranial elements, limiting comparison with other genera. Three major morphotypes have been recognised within Choristodera: longirostrine neochoristoderes with short-necks, and brevirostrine non-neochoristoderes with either short or long necks. The morphotype of Khurendukhosaurus was uncertain, although it had been inferred to be long-necked, based on cervical and caudal vertebral morphology shared with the Chinese Hyphalosaurus and on the results of phylogenetic analysis that placed it within a clade of Sino-Japanese long-necked taxa. Newly discovered material from the Mongolian type locality, Khuren-Dukh, preserves most major postcranial elements of a single individual. This specimen confirms that Khurendukhosaurus belongs to the long-necked morphotype, in having at least 13 cervical vertebrae. Moreover, a new phylogenetic analysis supports the placement of Khurendukhosaurus as a sister group of the Hyphalosaurus + Shokawa clade. Based on the new material, Khurendukhosaurus is estimated to have been roughly 1 m in total length, placing it at the upper end of the size range for long-necked choristoderes.
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