نتایج جستجو برای: middle cretaceous

تعداد نتایج: 163403  

Journal: :Royal Society open science 2016
Karl T Bates Philip D Mannion Peter L Falkingham Stephen L Brusatte John R Hutchinson Alejandro Otero William I Sellers Corwin Sullivan Kent A Stevens Vivian Allen

The colossal size and body plan of sauropod dinosaurs are unparalleled in terrestrial vertebrates. However, to date, there have been only limited attempts to examine temporal and phylogenetic patterns in the sauropod bauplan. Here, we combine three-dimensional computational models with phylogenetic reconstructions to quantify the evolution of whole-body shape and body segment properties across ...

1998
Scott L. Wing Lisa D. Boucher

The first flowering plant fossils occur as rare, undiverse pollen grains in the Early Cretaceous (Valanginian-Hauterivian). Angiosperms diversified slowly during the Barremian-Aptian but rapidly during the Albian-Cenomanian. By the end of the Cretaceous, at least half of the living angiosperm orders were present, and angiosperms were greater than 70% of terrestrial plant species globally. The r...

Journal: :Systematic biology 1999
J Alroy

Paleontologists long have argued that the most important evolutionary radiation of mammals occurred during the early Cenozoic, if not that all eutherians originated from a single common post-Cretaceous ancestor. Nonetheless, several recent molecular analyses claim to show that because several interordinal splits occurred during the Cretaceous, a major therian radiation was then underway. This c...

2007
Tien Shan CHUNSHENG WEI

A paleomagnetic study of rocks from the northern foot of the Tien Shan and the southern border of the Dzungar Basin, east of Urumqi (44.2°N, 86.0°E), spanning ages from middle Jurassic to early Tertiary was carried out to constrain the tectonic evolution in central Asia since Mesozoic time. Five middle Jurassic sites reveal a remagnetized direction close to the present Earth field in geographic...

2014
J. Alistair Crame Alan G. Beu Jon R. Ineson Jane E. Francis Rowan J. Whittle Vanessa C. Bowman

The extensive Late Cretaceous - Early Paleogene sedimentary succession of Seymour Island, N.E. Antarctic Peninsula offers an unparalleled opportunity to examine the evolutionary origins of a modern polar marine fauna. Some 38 modern Southern Ocean molluscan genera (26 gastropods and 12 bivalves), representing approximately 18% of the total modern benthic molluscan fauna, can now be traced back ...

2011
Zhuoheng Chen Kirk G. Osadetz Ping Tzeng

The middle Cretaceous Colorado Group of the Western Canadian Sedimentary Basin consists predominantly of mudstone deposited during major marine inundations interspersed with relatively thin sandstone and conglomerate beds. The Colorado Group petroleum system, containing a large portion of the light-medium oil and natural gas reserves within the Middle Jurassic to Cretaceous foreland basin succe...

2007
Helen K. Coxall Paul A. Wilson Paul N. Pearson Philip F. Sexton

—Digitate shell morphologies have evolved repeatedly in planktonic foraminifera throughout the Cretaceous and Cenozoic. Digitate species are usually rare in fossil and modern assemblages but show increased abundance and diversity at times during the Cretaceous and middle Eocene. In this paper we discuss the morphology and stratigraphic distribution of digitate planktonic foraminifera and establ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2011
Taylor S Feild Timothy J Brodribb Ari Iglesias David S Chatelet Andres Baresch Garland R Upchurch Bernard Gomez Barbara A R Mohr Clement Coiffard Jiri Kvacek Carlos Jaramillo

The flowering plants that dominate modern vegetation possess leaf gas exchange potentials that far exceed those of all other living or extinct plants. The great divide in maximal ability to exchange CO(2) for water between leaves of nonangiosperms and angiosperms forms the mechanistic foundation for speculation about how angiosperms drove sweeping ecological and biogeochemical change during the...

2015
Zoltán Csiki-Sava Eric Buffetaut Attila Ősi Xabier Pereda-Suberbiola Stephen L. Brusatte

The Late Cretaceous was a time of tremendous global change, as the final stages of the Age of Dinosaurs were shaped by climate and sea level fluctuations and witness to marked paleogeographic and faunal changes, before the end-Cretaceous bolide impact. The terrestrial fossil record of Late Cretaceous Europe is becoming increasingly better understood, based largely on intensive fieldwork over th...

2014
Jacek Szwedo

A short review of the state of the art of research on insects from the Cretaceous period is given. The recent achievements and priorities for future efforts are indicated. © 2014 Elsevier Ltd. All rights reserved. The Cretaceous, the geologic period from circa 145 to 66 million years (Ma) ago is a complex time period in Earth's history (Gale, 2000; Keller, 2008; Cohen et al., 2013). Generally s...

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