Triassic was some sort of end-Carnian extinction, when several herbivorous archosauromorph groups died out, while the large herbivorous therapsids—the kannemeyeriid dicynodonts and the traversodont cynodonts—were much reduced in the northern half of Pangaea (Laurasia). These extinctions within the Triassic and at its end allowed the dinosaurs to expand into many niches that had become unoccupied. Dinosaurs became increasingly dominant, abundant and diverse, and remained that way for the next 150 million years. The true "Age of Dinosaurs" is during the following Jurassic and Cretaceous periods, rather than the Triassic. Triassic The Triassic () is a geologic period and system which spans
Jurassic are thought to have been shrub to small-tree sized. Ginkgo plants were particularly common in the mid- to high northern latitudes. In the Southern Hemisphere, podocarps were especially successful, while Ginkgos and Czekanowskiales were rare. In the oceans, modern coralline algae appeared for the first time. However, they were a part of another major extinction that happened within the next major time period. Jurassic The Jurassic (; from Jura Mountains) was a geologic period and system that spanned 56 million years from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period Mya.