Dinosaur Phylogenetic Tree

WHAT DINOSAUR DID THESE BONES COME FROM? STUDENT RESOURCE 2019•2020

DINOSAUR PHYLOGENETIC TREE

ORNITHISCHIA (ORDER) There are many different groups of Ornithischia. They are characterized by their unusual-looking skulls, spines, and tails. Most walked on four legs, were herbivores, and had teeth that were great at grinding plants. Scientists think that they roamed the land in large herds of hundreds. Thyreophora (type) Thyreophora were herbivores that are known for the unique “armor” that lined their back and served as a shield to protect them from predators. In some thyreophora, this armor was very elaborate set of spikes and/or plates. Stegosaurus is part of this group of dinosaurs. Ornithopoda (type) This group of medium to large-sized dinosaurs did not have any body armor but many did have uniquely shaped sinus regions in their skull. They mostly walked on two feet and ate plants. One type of well-known ornithopoda is the duck-billed Hadrosaur. Marginocephalia (type) Marginocephalia dinosaurs are characterized by a bony ridge at the back of their skull. This group of herbivores includes the thick skulled pachycephalosaurids and the horned ceratopsians.

SAURISCHIA (ORDER) Saurischia dinosaurs are the ancestors of birds and have hipbones similar to lizards. This branch is divided up into two distinct groups: the two-legged, mostly carnivorous theropoda, and the four-legged, mostly herbivorous sauropoda. Theropoda (type) Theropoda were mostly carnivores. Their two strong legs and clawed feet made them fast and agile. Small arms allowed theropoda to grasp prey, while sharp teeth and strong jaws allowed them to easily tear flesh. Tryannosaurus rex is a well-known species of theropod. Sauropoda (type) Sauropoda were the largest dinosaurs that ever lived. They were mostly herbivores and usually walked on all four legs. Most had small heads and very long necks and tails. Scientists think that sauropoda formed herds to protect themselves from predators. Brachiosaurus and Apatosaurus are two types of sauropods that you may have heard of.