In every modern Dipnoan, crossopterygian, and Ganoid the air-bladder has an effective pneumatic duct.
In the archaic tail, enameled scales, and cartilaginous skeleton the crossopterygian shows its affinity with its Dipnoan ancestry.
The Ganoid differs from the crossopterygian in having the basal elements of the paired fins small and concealed within the flesh.
With these remains are found also scales possibly belonging to a crossopterygian fish (Eriptychius).
It is not unlikely that the crossopterygian gave rise to Amphibian and Dipnoan alike.
These are found in the garpike and in many genera of extinct Ganoid and crossopterygian fishes.
Any of a mostly extinct group of lobe-finned fishes of the order Crossopterygii, whose only living member is the coelacanth. One group of crossopterygians is thought to have evolved into terrestrial vertebrates beginning in the Devonian Period. See more at coelacanth.