Late Cretaceous Period

Late Cretaceous Dinosaurs

Eastern Asia-especially Mongolia-was an abundant source of dinosaur species. Tyrannosaurids from Asia were smaller and more primitive than their North American relatives. Dome-headed dinosaurs from Mongolia were much different from those in North America. The only armored dinosaurs from Asia were ankylosaurids, such as Talarurus and Tarchia. At least three types of sauropods survived in Mongolia to the latest Late Cretaceous: Nemegtosaurus, Opisthocoelicaudia, and Quaesitosaurus.

Talarurs plicatospineus
Brian Franczak
Talarurus plicatospineus

The most interesting dinosaurs discovered in Mongolia and China are the segnosaurs. Wide-bodied herbivores with powerful claws, Erlikosaurus, Segnosaurus, and Therizinosaurus are known from nowhere else in the world. Another interesting Asian group was the oviraptorids, including Conchoraptor and Oviraptor.

Small predators closely related to those in western North America abounded in eastern Asia. These included the sickle-clawed dromaeosaurids Adasaurus, Hulsanpes, and Velociraptor. Other small predators were the troodontid Saurornithoides and Elmisaurus, which was found in both Mongolia and Canada. Shanshanosaurus from China may have been related to North America's Aublysodon. Ostrich-dinosaurs were quite unusual in Mongolia. Some were more primitive than their American relatives, while others were quite advanced, such as Anserimimus and the huge Gallimimus.

Europe was covered by a continental sea that divided it up into islands. This led to the evolution of dwarf dinosaurs known as "island endemics." Struthiosaurus was a miniature nodosaurid; Magyarosaurus and Hypselosaurus were small titanosaurids; and Rhabdodon and Craspedodon were small iguanodontids. Only Telmatosaurus, a primitive hadrosaurid, was about "normal" size.

The Gondwanaland continents had different Late Cretaceous dinosaurs. Almost all the Late Cretaceous Gondwanaland sauropods were titanosaurids. They were found mainly in South America, Africa, India, and Madagascar. Some titanosaurids were small, about 35 to 40 feet long, with ankylosaurlike armor scutes (plates) on their backs. Others were larger, such as Argyrosaurus.

The Late Cretaceous ended about 65 million years ago. All dinosaurs, mosasaurs, plesiosaurs, and pterosaurs vanished from the face of the earth. Furthermore, it seems that this extinction happened at almost the same time on all continents, in both northern and southern hemispheres. The rule of the dinosaurs ended with the end of the Mesozoic Era.