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The neopterygian clade is a super-division of the Actinopterygii, having arisen in the Late Permian and radiated since. Major complexifications of the feeding apparatus, reduction of the terminal portion of the backbone and modification to the braincase are its main characteristics.
The tail-fin rays became completely symmetrical, and body scales became cycloidal, thinner and more flexible, enabling more effective swimming undulations. There are four main groups of neopterygians: the gars (lepisosteids), semionotids and other extinct forms (cf Evolution Pt2 homepage), bowfins and teleosts.