paedomorfia

Paedomorphosis is a phenomenon in biology where an adult organism retains juvenile physical features into maturity. This retention of juvenile characteristics can occur in various ways. For instance, it might involve the slowing or complete cessation of somatic development while the reproductive organs mature, leading to an adult that looks like a juvenile but can reproduce. Alternatively, it can involve the acceleration of reproductive development relative to somatic development.

This evolutionary process can result in significant changes in morphology. For example, the axolotl, a species of salamander, exhibits neoteny, a specific type of paedomorphosis, by retaining its larval gills and aquatic lifestyle throughout its adult life, even though its close relatives lose their gills and become terrestrial. Another example is found in certain invertebrates, where larval forms may become sexually mature and reproduce without undergoing metamorphosis into their adult forms.

Paedomorphosis is considered an important mechanism for evolutionary innovation, as it can lead to the development of novel traits and ecological niches. It is thought to have played a role in the evolution of many groups of organisms, including amphibians, fish, and invertebrates. The genetic and developmental mechanisms underlying paedomorphosis are a subject of ongoing research, with studies exploring the roles of gene regulation and hormonal pathways in controlling developmental timing.