Life History Evolution in Plethodontid Salamanders and the Evolutionary Ecology of Direct Development in Dusky Salamanders (Desmognathus)

摘要

The Plethodontidae, or lungless salamanders, is the largest of ten salamander families, with 478 currently-recognized species, representing 65% of all 738 salamander species (AmphibiaWeb 2019). Wake (2017) has provided a recent overview of the phylogeny, evolution, taxonomy, and biogeographic history of the family; his taxonomy, keyed to life-history mode is summarized in Table 1. Life-history variation in the family, which is greater than in any comparable vertebrate taxon, includes (1) amphibious biphasic species having aquatic larval forms that undergo complex metamorphoses to juvenile-to-adult forms, (2) aquatic paedomorphic species that fail to metamorphose and retain larval morphology through life, and (3) terrestrial direct-developing species that lack free-living aquatic larvae (Bonett et al. 2014; Bonett 2016; Beachy et al. 2017).