Dinosaurs are prehistoric reptiles that have lived on Earth from about 245 million years ago to the present. Modern birds are one kind of dinosaur because they share a common ancestor with non-avian dinosaurs. Non-avian dinosaurs (all dinosaurs besides birds), which are now extinct, varied greatly in shape and size.

Article Types of Dinosaurs Learn how many species have been discovered, and see photos and information about over 40 types of dinosaurs. Article Dinosaur Bones Discover what scientists can learn by studying fossils and how these fossils are stored in the Museum’s collections.

Article Types of Dinosaurs Learn how many species have been discovered, and see photos and information about over 40 types of dinosaurs. Article Dinosaur Bones Discover what scientists can learn by studying fossils and how these fossils are stored in the Museum’s collections.

For example, many more kinds of Late Cretaceous dinosaurs are known than Middle Jurassic dinosaurs because outcrops of Late Cretaceous are more numerous and more widely spread geographically than those of Middle Jurassic age.

NARRATOR: We can see this play out in the three major groups of dinosaurs. [The text “Ornithischians” moves to the bottom center of the screen, and all other illustrations and text disappear. Footage of a hadrosaurid hip appears.] NARRATOR: The ornithischian dinosaurs have the same hip bones as all dinosaurs,

August 13, 2012 Educator Materials Dinosaurs: Activities and Lesson Plans Resources to help students understand everything from basic dinosaur biology and evolution, to the tools and methods of modern paleontology. Article Dinosaur Eggs Fossilized eggs have helped scientists understand how dinosaurs reproduced and cared for their young.

To reconstruct the evolutionary relationships between different groups of dinosaurs, one must carefully study and analyze the anatomy, essentially searching for characteristics that are shared among different kinds of dinosaurs. These characteristics are then interpreted to have been present in the common ancestor and inherited by its descendants.

Aug 13, 2018 · At 122 feet (37 m) long and weighing an estimated 70 tons—or the equivalent of 10 African elephants—the sauropod species Patagotitan mayorum is one of the largest dinosaurs ever discovered. The species is so new that when The Titanosaur first went on view at the Museum in 2016, it hadn’t been given its scientific name—so the exhibit was ...

So in looking for non-avian dinosaur fossils in particular, paleontologists look for outcrops of sedimentary rocks that formed during the Mesozoic Era (251–65.6 million years ago), the geologic time period when non-avian dinosaurs lived.

Dinosaurs are prehistoric reptiles that have lived on Earth from about 228 million years ago to the present. Modern birds are one kind of dinosaur because they share a common ancestor with non-avian dinosaurs. Non-avian dinosaurs (all dinosaurs besides birds), which are now extinct, varied greatly in shape and size.