Fossils and Geologic Time Topics

Vertebrate Animals (Part 1)

Vertebrate animals are those that have backbones. They include: fish, amphibians, reptiles, birds, and mammals.


• Fish (Pisces) are aquatic creatures with skeletons, scales, and teeth that can be fossilized.

Shark tooth and fish
Skeletons and teeth are commonly the only parts preserved in fish fossils. A shark tooth (left) and a fish skeleton (right) are shown here. (Photographs by Parvinder Sethi)


• Amphibians (Amphibia) are four-footed aquatic and terrestrial creatures.  This group includes frogs, salamanders, and toads.  Very large amphibians existed in the Paleozoic.  Footprints and skeletons are the most common fossils.

570 to 245 million years ago


• Reptiles (Reptilia) are aquatic and terrestrial animals that breathe air their entire lives.  This group includes dinosaurs, turtles, snakes, lizards, crocodiles, and alligators.  Footprints and skeletons are the most common fossils.

Dinosaur footprint
Kyantipus minor (Photograph by Stan Johnson)

MapDinosaurs were a special type of reptile that lived only during the Mesozoic.  This footprint of Kyantipus minor tells us that dinosaurs walked around near Culpeper.