GEOL 104 Dinosaurs: A Natural History

Fall Semester 2006
Dinosaur History III: The Many Worlds of the Late Cretaceous

Dinosaur History Table

The Late Cretaceous saw some big changes in dinosaur communities. Asian dinosaurs migrate into North America, replacing many of the local forms. Because of this, dinosaurs (and other animals and plants) of Asia and western North America (together called Asiamerica) have a typical tyrannosaur-hadrosaur-ceratopsian community. Also includes smaller coelurosaurs among predators, omnivores, and herbivores; ankylosaurs and pachycephalosaurs among the herbivores.

Represented in western North America by the Moreno Hills Formation in the early Late Cretaceous and the Montana and Belly River Groups (among many others) in the late Late Cretaceous. Tyrannosaurus, Triceratops, Anatotitan, Pachycephalosaurus, and Ankylosaurus are all Montana Group dinosaurs.

In eastern North America, primitive representatives of the tyrannosaur-hadrosaur-ceratopsian community are found. Eastern and western North America separated by the Western Interior Seaway.

In the deserts of Asia, on the fringes of the tyrannosaur-hadrosaur-ceratopsian are a late-verison of the maniraptoran-ceratopsian-ankylosaur community. Best known from the Djadokhta Formation of Mongolia, which contains Velociraptor and Protoceratops.

In South America, India, and Madagascar (and possibly Africa, but no good fossils from there yet), an abelisaur-titanosaur community replaces the spinosaur-carnosaur-titanosaur community.

In Europe (an archipelago at the time), a mixture of primitive forms, a few unique taxa (like Rhabdodontidae), and the abelisaur-titanosaur community

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Last modified: 14 July 2006