Dactylioceras commune, ammonite Dimetrodon Castoroides ohioensis was a species

Castoroides ohioensis was a species of Giant Beaver

measured up to 13 feet and are actually very long incisors that continued to grow throughout the Mammoth's life

Ichthyostega stood alone as a transitional fossil between fish and tetrapods

USA Formation: Morrison Age: Late Jurassic

This specimen of Eldonia is from the lower Devonian of Alnif

Dactylioceras commune, ammonite Dimetrodon Castoroides ohioensis was a speciesDactylioceras 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