Actinopterygii: Systematics

Part 2 - the Neopterygii

Neopterygians ("new fins") used to be grouped into two main groups: the Teleostei, which includes most of the bony fish familiar to us today; and the Holostei, which included the living gars and bowfin along with several fossil groups. The Holostei, however, is a paraphyletic group -- that is, it includes some but not all descendants of an inferred common ancestor, which does not provide a firm basis for classification.

In the classification presented here, the Semionotiformes include the living gars as well as certain fossil fishes known as semionotids. The modern bowfin (Amia calva) is the lone survivor of a second main group of neopterygians, the Halecomorpha, which was once more diverse and abundant. Finally, the Teleostei include most living ray-finned fish, in addition to some fossil groups that are most closely related to them.

At the base of the neopterygian tree are several groups of early neopterygians, including the oldest known neopterygians of the Mississippian. For the moment, we have grouped these under their traditional name of "paleoniscoids," but remember that this is a paraphyletic grouping.

For more detailed information on bony fish classification, try the Actinopterygii pages from the Tree of Life at the University of Arizona.

This seven-language fish dictionary is available from the Marine Research Institute of Iceland.