This tooth is from the mandible of a Phytosaurus, a semiaquatic reptile that is now extinct. These reptiles had a long, pointed jaw with sharp cone-shaped teeth such as this one that were used to catch and eat fish. This tooth is 1.3cm thick and roughly 4cm x 3.5cm since the tooth's tip has broken off.
- Catalog Number:
- 52766
- Object/Specimen Description:
- Specimen Count:
- 1
- Precise Locality:
Southwest Colorado
- Locality:
- US High Plains and Rocky Mountains (ID, MT, ND, SD, WY, CO)
- Collecting Locality:
- North America, United States, Colorado
- Cabinet:
- 06
- Drawer/Shelf:
- 06
- Upper Level Taxonomy:
- Animalia, Chordata, Phytosauria, Phytosauridae
Reptiles first appeared on Earth about 300 million years ago (during the Pennsylvanian). Before then, all back-boned animals (vertebrates) were tied to the water, living in or near swamps. Their eggs were laid underwater. A set of gradual adaptations, such as thicker, scaly skin, allowed life on land to emerge. The biggest change was the development of an egg containing layers of membranes (amniotic membranes) to retain water, supply food, and store waste for an embryo. Two further innovations – the eggshell and internal fertilization – marked the first reptiles. Fertilization inside the female and shelled, amniotic eggs freed reptiles from aquatic life. They diversified into dinosaurs, crocodiles, lizards, snakes, turtles, tuataras, and birds as they colonized a variety of land habitats. For more than 100 million years, reptiles dominated the Earth. The largest reptiles were wiped out in the extinction event at the end of the Mesozoic, but their smaller descendants live on today.