Phylogenic distribution of limb regeneration capacity in adult Amphibia

Abstract

Limb regeneration was studied in 13 adult amphibian species in which regeneration had not previously been investigated. Limb regeneration was not exhibited by four anuran species: Pseudacris triseriata, Hyla squirilla, Hyla crucifer, and Bufo quercicus. Among the adult urodeles studied, normal regeneration was observed in five species: Ambystoma laterale, another Ambystoma jeffersonianum complex species, Eurycea bislineata, Plethodon cinereus, and Plethodon glutinosus. Limb regeneration was absent or heteromorphic in individuals of Siren intermedia and Ambystoma maculatum. Regeneration was not exhibited at all by adult Necturus maculosus, and Ambystoma tigrinum. The phylogenic distribution of limb regeneration capacity, in the 41 species of amphibians for which information is presently available, is reviewed and discussed.

Envirnmental conditions prerequisite for complete limb regeneration in the postmetamorphic adult land‐phase salamander, Ambystoma

“…Maintaining the salamander in an aquatic environment stimulates, to some extent, the breeding state whereby the salamander does not eat and essentially starves to death. The results in this report as well as those of Scadding (1977) support this idea. An additional consideration is that the salamanders are nocturnal in their activities, both in pursuit of their food source and in other ancillary activities.…”

“…The above results show that 1) postmetamorphic adult land-phase salamanders can survive under appropriate laboratory conditions for extended periods of time; 2) adult Scadding (1977) found that environmental conditions optimal for regeneration in the aquatic-phase urodeles (i.e., aquatic habitat with fresh liver as a food source) produced either heteromorphic or nonexistent regeneration (and death) in land-phase urodeles after a 60-day observation period. Our studies, as shown in Table 2, confirm this finding in that conditions for regeneration in aquatic species are detrimental to land-based species.…”

“…Scadding (1977), examining the phylogenetic distribution of regeneration, tested adult A. maculatum for its regenerative ability during a time period of 60 days and reported either nonexistent or heteromorphic regeneration within this species. The observation time was based on previously reported times for regeneration in aquatic model systems: 40 days for the newt (Iten and Bryant, 1973); "30+" days for the axolotl (Tank et al, 1976;Farber, 1959); and 44 days for the larval salamander (Stocum, 1979).…”

“…Our results show that adult A. maculatum will completely regenerate within a time period of 255 to 300 days postamputation. The observation period used by Scadding (1977) for complete regeneration in adult A. maculat u m was only one fourth to one fifth the actual time needed for complete regeneration to occur in this same species. The additional data presented here show that complete regeneration is also possible in A. tigranum (155 to 180 dpa), A. teranum (215 to 250 dpa), and A. aniiulatum (324 to 370 dpa).…”

“…We believe an alternate explanation, that the adult land-phase forms retain the capacity to regenerate tissues, but this cannot be expressed when land-phase animals are maintained in laboratory environments established for aquatic-phase animals, i.e., newts, axolotls, and/or larval salamanders. Indeed, it has been shown that adult landphase forms will survive for only 2 to 3 months under conditions usually employed for studies on regeneration in aquatic forms (Scadding, 1977). Since studies pertaining to regeneration rates in newts have shown that the rates are greatly affected by adverse environmental conditions (Schauble, 1972;Schauble and Nentwig, 1974;Maier and Singer, 19771, it seems plausible that the reported inability of the adult land-phase salamander to regenerate a limb may be due to adverse laboratory conditions rather than actual loss of the intrinsic capacity to regenerate.…”