The gradual decline of the dinosaurs—fact or fallacy?

  title={The gradual decline of the dinosaurs—fact or fallacy?},
  author={Dale A. Russell},
  • D. Russell
  • Published 1984
  • Environmental Science, Geography
  • Nature
Both great dinosaurian orders (Saurischia and Ornithischia) were major components of terrestrial vertebrate faunas for ∼150 Myr. The prevailing view is that dinosaurs attained an evolutionary acme late in the Cretaceous, after which they gradually declined in taxonomic diversity over ∼10 Myr to their extinction 63 Myr ago1–6. The postulated decline is usually supported by comparing diversity levels in 76 Myr-old and 64 Myr-old dinosaurian assemblages from North America. The resulting… 

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.

Dinosaur biodiversity declined well before the asteroid impact, influenced by ecological and environmental pressures

It is found that the decline of dinosaurs was likely driven by global climate cooling and herbivorous diversity drop, and the latter is likely due to hadrosaurs outcompeting other herbivores.

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.

Competition structured a Late Cretaceous megaherbivorous dinosaur assemblage

It is concluded that competition structured comparable megaherbivorous dinosaur communities throughout the Late Cretaceous of western North America and that contemporaneous taxa are demonstrably well-separated in ecomorphospace at the family/subfamily level.

New data on pachycephalosaurid dinosaurs (Reptilia: Ornithischia) from North America

In this paper several new significant specimens of pachycephalosaurid dinosaurs from Upper Cretaceous strata of Canada and the United States are described and figured. The domes of an unusual

Latest Cretaceous occurrence of nodosaurid ankylosaurs (Dinosauria, Ornithischia) in Western North America and the gradual extinction of the dinosaurs

ABSTRACT The presence of nodosaurid ankylosaurs in the Lance, Hell Creek, and Laramie formations of western North America is confirmed, thereby extending the geochronological range of this family

A new basal ornithopod dinosaur (Frenchman Formation, Saskatchewan, Canada), and implications for late Maastrichtian ornithischian diversity in North America

Identification of a third species of Thescelosaurus from the late Maastrichtian of North America suggests that this taxon was more diverse than previously recognized, and shows an increase in diversity from the Campanian through theLate MaastRichtian, contrasting the trends seen in most other ornithischian clades.

Are marine and nonmarine extinctions correlated

Recent papers in Eos have debated the possible relationships between marine mass extinctions, comet showers, and volcanism [Alvarez, 1986; Officer and Grieve, 1986], and ail three might be linked

Geological setting of vertebrate microfossil localities across the Cretaceous–Paleogene boundary in southwestern Saskatchewan, Canada

The Frenchman and Ravenscrag formations of southwestern Saskatchewan, Canada, record an apparently continuous sequence of nonmarine clastic sediments across the Cretaceous–Paleogene (K–Pg) boundary.



New data on pachycephalosaurid dinosaurs (Reptilia: Ornithischia) from North America

In this paper several new significant specimens of pachycephalosaurid dinosaurs from Upper Cretaceous strata of Canada and the United States are described and figured. The domes of an unusual

Phanerozoic Land-Plant Diversity in North America

Total and within-flora data suggest that the track of North American land-plant diversity has been similar in nature, but not in timing, to that inferred for marine invertebrates.

Catopsalis (Multituberculata) from Asia and North America and the problem of taeniolabidid dispersal in the Late Cretaceous

Djadochtatherium Simpson, 1925 is a junior synonym of Catopsalis Cope, 1882. Known species of Catopsa!ts (Djadochtathertum inclUded) form a morphological sequence, beginning with Asian ?Late

Phanerozoic marine diversity and the fossil record

Strong correlations between various local and global estimates of Phanerozoic marine diversity for taxa below the ordinal level indicate a single pattern of change underlying all data on fossil

Taxonomic diversity estimation using rarefaction

  • D. Raup
  • Environmental Science, Geology
  • 1975
Application of rarefaction to several large samples of post-Paleozoic echinoids (totaling 7,911 species) confirms the utility of the method and shows that the observed increase in the number of echinoid families since the Paleozoic is real in the sense that it cannot be explained solely by the increase in numbers of preserved species.

An albertosaur from the Hell Creek Formation of Montana

A bstract —An incomplete albertosaur skeleton from the Hell Creek Fm. of central Montana, differs from Tyrannosaurus rex in the proportions of the postcranial elements, and in the form of the artic­


The fragmentary skull of a moderate-size theropod is described from the Maestrichtian of central Montana. Premaxillary teeth are D-shaped in cross section, frontals are thin dorsoventrally with no

Rarefaction and rarefiction-the use and abuse of a method in paleoecology

Rarefaction is a method for comparing community diversities that has consistently been abused by paleoecologists: here its assumptions are clarified and advice given on its application. Rarefaction