Colorado State Fossil

Plated Dinosaur

(Stegosaurus stenops)

Adopted on April 28, 1982

A fourth-grade class campaigned across the state for two years to designate Stegosaurus a Colorado symbol. Their efforts culminated in an executive order issued by the governor on April 28, 1982 making the Plated Dinosaur, Stegosaurus stenops, the official state fossil.

Description of the Colorado State Fossil

The Stegosaurus lived in the area we now know as Colorado one hundred and fifty million years ago during the Mesozoic era in the Jurassic period. It is believed that a typical Stegosaurus weighed ten tons though its brain weighed only two and one-half ounces. There are only 6 skeletons of the Stegosaurus on public display in the United States, one of which may be viewed at the Museum of Natural History in Denver. This skeleton was discovered by a teacher and students from Canon City High School

The first Stegosaurus fossil was discovered in Colorado by M. P. Felch in 1877. Stegosaur fossils are widely distributed from the United States to China showing how successful this dinosaur group was.

There are many different types of stegosaur, of which Stegosaurus is the largest. Fossils from three different species of Stegosaurus have now been identified from the Morrison Formation in the western USA. These finds have included complete skeletons and juveniles.

Stegosaurus had 17 bony plates that were embedded in its back - the plates ran along the Stegosaurus' back and tail in two rows, and the plates alternated in alignment. The largest of these triangular plates was about 2.5 ft (76 cm) tall and just as long. Stegosaurus also had spikes at the end of its flexible tail (these are called thagomizers).

Although Stegosaurus was about the size of a bus, it had a small head (the size of a horse's head) and a brain that was only the size of a walnut!

Characteristics

Stegosaurus was a herbivorous "bird-hipped" dinosaur, which cropped vegetation with its powerful beaked mouth.

Teeth: a toothless beak, small cheek teeth
Length: 9 meters (30 feet)
Food: plants and leaves
Height: 2.75 meters ( 9 feet)
How it walked: walked on four legs
Weight: 1,400 kilograms (3,000 pounds)
Period: Jurassic
Type of feeder: plant eater (herbivore)

Taxonomic Hierarchy of the Plated Dinosaur

Kingdom	Animalia (animals)
Phylum	Chordata (having a spinal cord)
Subphylum	Vertebrata -- vertebrates
Class	Archosauria (diapsids with socket-set teeth, etc.)
Order	Ornithischia - bird-hipped dinosaurs
Family	Stegosauridae
Genus	Stegosaurus
Species	Stegosaurus stenops

State Fossils

Most US states have made a state fossil designation, in many cases during the 1980s. It is common to designate one species in which fossilization has occurred, rather than a single specimen, or a category of fossils not limited to a single species.

Some states that lack a "state fossil" have nevertheless singled out a fossil for formal designation such as a state dinosaur, rock, gem or stone.

fossil (fos‧sil)
n.
1. A remnant or trace of an organism of a past geologic age, such as a skeleton or leaf imprint, embedded and preserved in the earth's crust.
2. One, such as a rigid theory, that is outdated or antiquated.

adj.
1. Characteristic of or having the nature of a fossil.
2. Being or similar to a fossil.
3. Belonging to the past; antiquated.

[From Latin fossilis, dug up, from fossus, past participle of fodere, to dig.]

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