The decrease in vessel element length and imperforate tracheary element length over time, as well as the exclusively upright cells of rays, are hallmarks of paedomorphosis
in Ambystoma talpoideum: effects of density, food, and pond drying.
The terms paedomorphosis
and progenesis have been used for those two phenomena, respectively, but the terms are zoological ones and are doubtfully applicable to organisms with an open system of growth.
Many populations of the western tiger salamander, Ambystoma mavortium, express facultative paedomorphosis
2005) viewed the occurrence of paedomorphosis
as evidence against recapitulation.
(juvenile features retained in adults) is a mechanism of evolutionary change sometimes seen as simplification of the body, a feature common in mesopelagic animals (Herring, 2002) and may be the case with C.
1987), wing morphology polymorphisms in insects (Harrison 1980; Roff 1986), seasonal wing color polymorphisms in lepidopterans (Watt 1969; Kingsolver 1995) and facultative paedomorphosis
in salamanders (Sprules 1974a; Semlitsch 1987; Whiteman 1994b).
Russell (1916), for example, provides a long list of reasons to reject the biogenetic law as universal, including the existence of heterochronic processes such as paedomorphosis
Approximately 10% of all species of salamander exhibit paedomorphosis
Brooding and paedomorphosis
in the deep-water feather star Comatilia iridometriformis (Echinodermata: Crinoidea).
Alternative evolutionary mechanisms of facultative paedomorphosis
Molecular evidence for multiple episodes of paedomorphosis
in the family Hydractiniidae.