Gradual Dinosaur Extinction and Simultaneous Ungulate Radiation in the Hell Creek Formation

  title={Gradual Dinosaur Extinction and Simultaneous Ungulate Radiation in the Hell Creek Formation},
  author={Robert Evan Sloan and J. Keith Rigby and Leigh M. Van Valen and Diane L. Gabriel},
  pages={629 - 633}
Dinosaur extinction in Montana, Alberta, and Wyoming was a gradual process that began 7 million years before the end of the Cretaceous and accelerated rapidly in the final 0.3 million years of the Cretaceous, during the interval of apparent competition from rapidly evolving immigrating ungulates. This interval involves rapid reduction in both diversity and population density of dinosaurs. The last dinosaurs known are from a channel that contains teeth of Mantuan mammals, seven species of… 

Sudden extinction of the dinosaurs: latest Cretaceous, upper Great Plains, USA.

Results of a three-year field study of family-level patterns of ecological diversity of dinosaurs in the Hell Creek Formation show no evidence of a gradual decline of dinosaurs at the end of the Cretaceous, in agreement with an abrupt extinction event such as one caused by an asteroid impact.

The extinction of the dinosaurs

The abruptness of the dinosaur extinction suggests a key role for the bolide impact, although the coarseness of the fossil record makes testing the effects of Deccan volcanism difficult.

The last polar dinosaurs: high diversity of latest Cretaceous arctic dinosaurs in Russia

Dinosaur eggshell fragments indicate that at least several latest Cretaceous dinosaur taxa could reproduce in polar region and were probably year-round residents of high latitudes, strongly questions hypotheses according to which dinosaur extinction was a result of temperature decline, caused or not by the Chicxulub impact.

Shape of Mesozoic dinosaur richness

The richness of Mesozoic Dinosauria is examined through the use of a new global database. Mesozoic dinosaurs show a steadily increasing rate of diversification, in part attributable to the

Dinosaur morphological diversity and the end-Cretaceous extinction.

There was no universal biodiversity trend and the intensively studied North American record may reveal primarily local patterns, but at least some dinosaur groups did endure long-term declines in morphological variability before their extinction.

Dinosaurs and the Cretaceous Terrestrial Revolution

  • G. LloydK. Davis M. Benton
  • Environmental Science, Geography
    Proceedings of the Royal Society B: Biological Sciences
  • 2008
It is concluded that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR, and major diversification shifts occurred largely in the first one-third of the group's history.

Extinction and recolonization of coastal megafauna following human arrival in New Zealand

New Zealand was the world's last large landmass to be colonized by humans, and its exceptional archaeological record documents a vast number of vertebrate extinctions in the immediate aftermath of Polynesian arrival, which presents an outstanding opportunity to test for rapid biological responses to extinction.

Geochemical environmental changes and dinosaur extinction during the Cretaceous-Paleogene (K/T) transition in the Nanxiong Basin, South China: Evidence from dinosaur eggshells

The complex patterns of trace elements including Ir and isotope distributions in the three K/T sections of the Nanxiong Basin prove the existence of two environmental events in the latest Cretaceous

Vertebrate faunal changes through Lancian and Puercan time in southern Wyoming

We summarize faunal changes through the thickest and one of the most complete records of terrestrial vertebrates spanning Lancian (∼latest Cretaceous) and Puercan (∼earliest Paleocene) ages, the type



Terminal Cretaceous Extinctions in the Hell Creek Area, Montana: Compatible with Catastrophic Extinction

Establishment of the transitional faunas in Paleocene channels that cut down through the Cretaceous-Tertiary boundary renders the terrestrial faunal record compatible with the marine record and with catastrophic extinction.

Upper Cretaceous–Paleocene biostratigraphy and magnetostratigraphy, Hell Creek and Tullock Formations, northeastern Montana

Fossils from the Hell Creek and Tullock Formations in northeastern Montana provide detailed documentation of terrestrial faunal and floral evolution during latest Cretaceous (Lancian) and early

Cretaceous Mammals from Montana

Four families (Eucosmodontidae, Taeniolabididae, Leptictidae, Arctocyonidae) and one order (Condylarthra) of Tertiary mammals are extended into the Cretaceous and multituberculate classification is revised.

Cretaceous-Paleocene Terrestrial Faunas of India: Lack of Endemism During Drifting of the Indian Plate

It is suggested that a dispersal corridor, consisting of presently submerged aseismic elements (the Mascarene Plateau and the Chagos-Laccadive Ridge), existed between these landmasses about 80 million years ago as India drifted close to eastern Africa.

Magnetostratigraphy, biostratigraphy and geochronology of Cretaceous–Tertiary boundary sediments, Red Deer Valley

Integrated magnetostratigraphic and biostratigraphic data for continental Cretaceous–Tertiary boundary sediments in Alberta allow a correlation with recognised sea floor magnetic anomalies 29 and 30.

The Earliest Primates

The known range of the Primates is extended down from the middle Paleocene to the early Paleocene and late Cretaceous by a new genus and two new species from Montana, Purgatorius unio and P.

The Enigma of the Extinction of the Dinosaurs

One of the more interesting contributions of paleontology to general knowledge is evidence that giant reptiles were once the dominant life forms on our planet. During the past two centuries some 5000

Land plant evidence compatible with gradual, not catastrophic, change at the end of the Cretaceous

  • L. Hickey
  • Environmental Science, Geography
  • 1981
Field study of the fossil and sedimentary record across the Cretaceous–Tertiary (K–T) boundary in Wyoming and Montana has been combined here with a reassessment of the published record of terrestrial