Are paedomorphs actual larvae?. Issue 6 (12th February 2021)

• Record Type: Journal Article
• Authors: Tribondeau, Alicia; Sachs, Laurent M.; Buisine, Nicolas
• Other Names: McCusker Catherine guestEditor.; Monaghan James guestEditor.; Whited Jessica guestEditor.
• Is Part Of: Developmental dynamics. Volume 250:Issue 6(2021)
• Page Start: 779
• Page End: 787
• Publication Date: 2021-02-12
• Subjects: metamorphosis -- paedomorphosis -- post embryonic transition -- thyroid hormone signaling -- urodeles; Morphogenesis -- Periodicals; Anatomy -- Periodicals; Anatomie -- Périodiques; Biologie du développement -- Périodiques; 571.833
• DOI: 10.1002/dvdy.304
• Languages: English
• ISSNs: 1058-8388

Abstract

Abstract: Amphibians display very diverse life cycles and development can be direct, where it occurs in ovo and a juvenile hatches directly, or biphasic, where an aquatic larva hatches and later undergoes metamorphosis followed by sexual maturation. In both cases, metamorphosis, corresponds to the post embryonic transition (PETr). A third strategy, only found in Urodeles, is more complex as larvae reach sexual maturity before metamorphosis, which can become accessory. The resulting paedomorphs retain their larval characters and keep their aquatic habitat. Does it mean that paedomorphs do not undergo PETr? Recent work using high throughput technologies coupled to system biology and developmental endocrinology revisited this question and provided novel datasets indicating that a paedomorph's "larval" tissue undergoes a proper developmental transition. Together with historical data, we propose that this transition is a marker of the PETr, which would be distinct from metamorphosis. This implies that (a) complex life cycles would result from the uncoupling of PETr and metamorphosis, and (b) biphasic life cycles would be a special cases where they occur simultaneously. Key Findings: Metamorphosis is widely believed to be the post embryonic transition for all amphibians Paedomorphs retain larval characters and are perceived as larvae even as reproductive adults Recent genomic data suggest a cryptic post‐embryonic transition between larval and paedomorphic stages Metamorphosis may be uncoupled from post embryonic transition in paedomorphic species