نتایج جستجو برای: cretaceous

تعداد نتایج: 9055  

2014
Fenglu Han Wenjie Zheng Dongyu Hu Xing Xu Paul M. Barrett

A new ankylosaurid, Chuanqilong chaoyangensis gen. et sp. nov., is described here based on a nearly complete skeleton from the Lower Cretaceous Jiufotang Formation of Baishizui Village, Lingyuan City, Liaoning Province, China. Chuanqilong chaoyangensis can be diagnosed on the basis of two autapomorphies (glenoid fossa for quadrate at same level as the dentary tooth row; distally tapering ischiu...

2017
Amy Klein Curtis W. Anderson

In 1840, John Phillips invented the term Mesozoic, which means “Middle Animal”. The Mesozoic Era was a geological time period that lasted 180 million years and is composed of three smaller time periods, Triassic, Jurassic and the Cretaceous. The cretaceous period lasted 81 million years, which during that time there was a continual rule of dinosaurs and other reptiles, the start of flowering pl...

2013
Wu-Bin Yang He-Cai Niu Wei-Dong Sun Qiang Shan Yong-Fei Zheng Ning-Bo Li Cong-Ying Li Nicholas T. Arndt Xing Xu Yu-Hang Jiang Xue-Yuan Yu

Cretaceous represents one of the hottest greenhouse periods in the Earth's history, but some recent studies suggest that small ice caps might be present in non-polar regions during certain periods in the Early Cretaceous. Here we report extremely negative δ(18)O values of -18.12‰ to -13.19‰ for early Aptian hydrothermal zircon from an A-type granite at Baerzhe in northeastern China. Given that ...

Journal: :Biology letters 2011
Paul M Barrett Roger B J Benson Thomas H Rich Patricia Vickers-Rich

A cervical vertebra from the Early Cretaceous of Victoria represents the first Australian spinosaurid theropod dinosaur. This discovery significantly extends the geographical range of spinosaurids, suggesting that the clade obtained a near-global distribution before the onset of Pangaean fragmentation. The combined presence of spinosaurid, neovenatorid, tyrannosauroid and dromaeosaurid theropod...

2016
Wilson R. Lourenço

A preliminary study on fossil scorpions found in amber, from the Lower Cretaceous through the Palaeocene and up to the Miocene is proposed. Scorpions remain rare among the arthropods found trapped in amber. Only 24 specimens are known from Cretaceous amber, representing eight families and subfamilies, ten genera and 21 species; in parallel, 10 specimens have been recorded from Baltic amber repr...

2017
Tom Brougham Elizabeth T. Smith Phil R. Bell

The fossil record of Australian pterosaurs is sparse, consisting of only a small number of isolated and fragmentary remains from the Cretaceous of Queensland, Western Australia and Victoria. Here, we describe two isolated pterosaur teeth from the Lower Cretaceous (middle Albian) Griman Creek Formation at Lightning Ridge (New South Wales) and identify them as indeterminate members of the pteroda...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1992
S B Hedges C A Hass L R Maxson

The geological association of the Greater Antilles with North and South America in the late Cretaceous led to the hypothesis that the present Antillean biota reflects those ancient land connections. Molecular data from diverse West Indian amphibians and reptiles and their mainland relatives support a more recent derivation of the Antillean vertebrate fauna by overwater dispersal. The catastroph...

Journal: :Biology letters 2015
Silvia Danise Nicholas D Higgs

We report fossil traces of Osedax, a genus of siboglinid annelids that consume the skeletons of sunken vertebrates on the ocean floor, from early-Late Cretaceous (approx. 100 Myr) plesiosaur and sea turtle bones. Although plesiosaurs went extinct at the end-Cretaceous mass extinction (66 Myr), chelonioids survived the event and diversified, and thus provided sustenance for Osedax in the 20 Myr ...

Journal: :Proceedings. Biological sciences 2001
J Cracraft

The fossil record has been used to support the origin and radiation of modern birds (Neornithes) in Laurasia after the Cretaceous-Tertiary mass extinction event, whereas molecular clocks have suggested a Cretaceous origin for most avian orders. These alternative views of neornithine evolution are examined using an independent set of evidence, namely phylogenetic relationships and historical bio...

2007
ALAN H. TURNER SUNNY H. HWANG MARK A. NORELL

A new theropod dinosaur, Shanag ashile, from the Early Cretaceous Öösh deposits of Mongolia is described here. The new specimen (IGM 100/1119) comprises a well-preserved right maxilla, dentary, and partial splenial. This specimen exhibits a number of derived theropod features, including a triangular anteriorly tapering maxilla, a large antorbital fossa, and maxillary participation in the caudal...

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