peramorphosis Any outcome arising from evolutionary changes in developmental rates (see heterochrony) that involves the addition of new stages to the end of the ancestral development sequence. Peramorphic forms may arise either by acceleration or by hypermorphosis and conform to the theory of recapitulation. In contrast, paedomorphic forms (see paedomorphosis), in which a new stage is added within the developmental sequence, do not exhibit recapitulation.

peramorphosis Evolutionary change that results in the descendant incorporating all the ontogenetic stages of its ancestor, including the adult stage, in its ontogeny, so that the adult descendant ‘goes beyond’ its ancestor. It may occur by acceleration, hypermorphosis, or predisplacement. Such progeny will show recapitulation of phylogeny.

peramorphosis Evolutionary change that results in the descendant incorporating all the ontogenetic stages of its ancestor, including the adult stage, in its ontogeny, so that the adult descendant ‘goes beyond’ its ancestor. It may occur by acceleration, hypermorphosis, or predisplacement.

peramorphosis Evolutionary change that results in the descendant incorporating all the ontogenetic stages of its ancestor, including the adult stage, in its ontogeny, so that the adult descendant ‘goes beyond’ its ancestor. It may occur by acceleration, hypermorphosis, or predisplacement.