Limb regeneration in adult amphibia

Abstract

This paper reports a histological analysis of limb regeneration capacity in 20 species of amphibians. These data, along with a survey of other species reported in the literature, are used as a basis for the following generalizations. (1) Limb regeneration in the amphibians is not an all-or-none process, but regenerative capacity covers a continuum from normal regeneration to total absence of regenerative ability. (2) In adult anurans, regenerative outgrowth is common in discoglossids and pipids, occurs frequently in hylids, rarely in ranids, and has never been reported in bufonids. In the anurans, there is no correlation between size and regenerative capacity. (3) In the urodeles, limb regeneration capacity is correlated with size. Urodele species with a mean snout–vent length over 100 mm regenerate heteromorphically or not at all. Those under 75 mm regenerate consistently normally. Those species of intermediate size give variable responses to limb amputation, and may regenerate normally, heteromorphically, or not at all. Hypotheses that might explain differences in regenerative ability are discussed.

Latent regeneration abilities persist following recent evolutionary loss in asexual annelids

“…3), malformed regenerates in fish fins (4), and hypomeric, nonfunctional outgrowths in amphibians (12). However, we found that species with superficially similar amputation outcomes can vary dramatically in the extent to which regeneration has been abrogated.…”

“…Although many animals capable of agametic reproduction have extraordinary regenerative abilities (21), and asexual and regenerative developmental processes can overlap substantially (1,11,25), naidines clearly demonstrate that regeneration is far from universal among agametically reproducing species, even in species, such as naidines, in which agametic reproduction is derived from regeneration (26). Furthermore, naidines join the small but growing list of examples showing that loss of regenerative abilities is not necessarily accompanied by large-scale changes in morphological complexity (2,4,5,12). Naidines all share a similar body plan, and species that cannot regenerate do not differ in any consistent way from fully regenerating species.…”

“…However, with few exceptions (e.g., 4,6,12), regeneration research has focused almost exclusively on regenerating species or on broad comparisons between distantly related regenerating and nonregenerating groups (e.g., amphibians vs. mammals) too deeply diverged to reveal much about the mechanism of regeneration loss. What types of changes are correlated with regeneration loss?…”

Perspective: Appendage regeneration in amphibians and some reptiles derived from specific evolutionary histories

“…In some species the fins can largely regenerate and also part of the eye, optic nerve, heart, and spinal cord (Cuervo, Hernandez‐Martinez, Chimal‐Monroy, Merchant‐Larios, & Covarrubias, ; Nakatani, Kawakami, & Kudo, ). In prevalently terrestrial urodeles of larger sizes (Scadding, ; Scadding, ; Alibardi, unpublished observations on Salamandra salamandra ), in caecilians, in anurans after metamorphosis (Figure ), in the following amniotes (Figure g,h), tissue and organ proliferation can no longer give rise to a morphogenetic process of regeneration. However, in small species of urodeles living in very humid and warm condition, such as the plethodontid salamander Bolitoglossa ramosi , a slow process of regeneration has been reported (Arenas‐Gomez, Gomez‐Molina, Zapata, & Delgado, ).…”

Effects of tunicamycin on retinoic acid induced respecification of positional values in regenerating limbs of the larval axolotl, Ambystoma mexicanum

“…Urodele amphibians, including the axolotl Ambystoma mexicanum, possess a remarkable capacity for epimorphic limb regeneration (Scadding, 1981;Wallace, 1981). Following limb amputation, all limb structures which lie distal to the plane of amputation are regenerated, so that the complete limb is restored (Niazi and Saxena, 1978;Maden, 1983).…”