When Did Actinopterygii Appear?
When Did Actinopterygii Appear? They first appear in the fossil record about 200 million years ago (as the family Leptolepididae), with their homocercal caudal fin and caudal skeleton already fully developed. When did actinopterygii evolve? The origin of Actinopterygii is minimally constrained to the late Silurian (Ludlow; ca. 425 Ma) by the first sarcopterygians (Zhu