Definition that contains pennsylvanian period
- myxinikela siroka fossil hagfish of the Pennsylvanian period (c. 300 million years ago) that resembled modern hagfishes
- order cordaitales extinct plants having tall arborescent trunks comparable to or more advanced than cycads; known from the Pennsylvanian period; probably extinct since the Mesozoic era
- cordaitales extinct plants having tall arborescent trunks comparable to or more advanced than cycads; known from the Pennsylvanian period; probably extinct since the Mesozoic era