In heterochrony, this is the process whereby if the rate of shape change of an organism is increased, or its period of operation is extended, the descendant adult passes morphologically beyond the ancestor. This can occur by hypermorphosis, acceleration, or pre-displacement. The concept of peramorphosis somewhat equates and supersedes the Biogenetic Law. Compare to paedomorphosis. See Briggs and Crowther (1990), pp. 111-119.

In developmental biology, peramorphosis is a phylogenetic change in which individuals of a species mature past adulthood and take on hitherto unseen traits. It is the reverse of pedomorphosis.