نتایج جستجو برای: cretaceous
تعداد نتایج: 9055 فیلتر نتایج به سال:
Many isolated dinosaur bones and teeth have been recovered from Cretaceous rocks in India, but associated remains are exceedingly rare. We report on the discovery of associated cranial and postcranial remains of a new abelisaurid theropod from latest Cretaceous rocks in western India. The new taxon is characterized by exceptionally elongated supratemporal fenestrae and a unique median nasofront...
The Northern Dabie Complex in east central China lies between the Sino–Korean plate to the north and the Yangtze plate to the south. The Northern Dabie Complex has been variously proposed to represent a Paleozoic magmatic arc on the Sino–Korean plate, an exhumed piece of subducted Yangtze plate crust, or crust produced almost entirely by Cretaceous extension-related magmatism. Trace element com...
Three large lamniform shark vertebrae are described from the Lower Cretaceous of Texas. We interpret these fossils as belonging to a single individual with a calculated total body length of 6.3 m. This large individual compares favorably to another shark specimen from the roughly contemporaneous Kiowa Shale of Kansas. Neither specimen was recovered with associated teeth, making confident identi...
Food web recovery from mass extinction is poorly understood. We analyzed insect-feeding damage on 14,999 angiosperm leaves from 14 latest Cretaceous, Paleocene, and early Eocene sites in the western interior United States. Most Paleocene floras have low richness of plants and of insect damage. However, a low-diversity 64.4-million-year-old flora from southeastern Montana shows extremely high in...
We describe a new genus and species of Histeridae from Upper Cretaceous Burmese amber, Amplectister tenax Caterino & Maddison, gen. & sp. n. This species represents the third known Cretaceous histerid, which, like the others, is highly distinct and cannot easily be placed to subfamily. It exhibits prosternal characters in common with Saprininae, but other characters appear inconsistent with thi...
Growth ring analysis on silicified coniferous woods from the Missão Velha Formation (Araripe Basin - Brazil) has yielded important information about periodicity of wood production during the Early Cretaceous in the equatorial belt. Despite warm temperatures, dendrological data indicate that the climate was characterized by cyclical alternation of dry and rainy periods influenced by cyclical pre...
Recent paleontological investigations of six sections fringing the Deccan volcanic outcrops of the Indian peninsula indicate that terrestrial faunas during the Cretaceous-Paleocene transition lacked the endemism predicted by geophysical models of an oceanically isolated Indian subcontinent. At the generic and familial level there is a close correspondence between the Cretaceous vertebrates of p...
A large number of recently collected specimens from Puerto Rico has yielded two new species including Palaeoxanthopsis tylotus and Eurytium granulosum, the oldest known occurrence of the latter genus. Cretaceous decapods are reported from Puerto Rico for the first time, and the Cretaceous fauna is similar to that of southern Mexico. Herein is included the first report of Pleistocene decapods fr...
We describe an enormous Late Cretaceous fossil bird from Kazakhstan, known from a pair of edentulous mandibular rami (greater than 275 mm long), which adds significantly to our knowledge of Mesozoic avian morphological and ecological diversity. A suite of autapomorphies lead us to recognize the specimen as a new taxon. Phylogenetic analysis resolves this giant bird deep within Aves as a basal m...
Overseas dispersals are often invoked when Southern Hemisphere terrestrial and freshwater organism phylogenies do not fit the sequence or timing of Gondwana fragmentation. We used dispersal-vicariance analyses and molecular timetrees to show that two species-rich frog groups, Microhylidae and Natatanura, display congruent patterns of spatial and temporal diversification among Gondwanan plates i...
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