Dactylioceras commune, ammonite Dimetrodon To the left is a

To the left is a picture of the Dracorex skull now on exhibit at the Children's Museum

and possibly plants

Like other members of their phylum they are spiny skinned

not divided into lobes

land-shells

Dactylioceras commune, ammonite Dimetrodon To the left is aDactylioceras was a widespread genus of ammonite from the Lower Jurassic period. They are generally small, averaging 2. 6 inches in diameter. Dactylioceras has a strong, ribbed shell. The ribs are slightly inclined forward, running over the outer edge, and either simple or forking at outer end. Though it eventually died out 180 million years ago, their style of ribbing was copied by numerous subsequent ammonite genera until the whole group became