Diversification and biogeographical history of Neotropical plethodontid salamanders

Abstract

The Neotropical bolitoglossine salamanders represent an impressive adaptive radiation, comprising roughly 40% of global salamander species diversity. Despite decades of morphological studies and molecular work, a robust multilocus phylogenetic hypothesis based on DNA sequence data is lacking for the group. We estimated species trees based on multilocus nuclear and mitochondrial data for all major lineages within the bolitoglossines, and used our new phylogenetic hypothesis to test traditional biogeographical scenarios and hypotheses of morphological evolution in the group. In contrast to previous phylogenies, our results place all Central American endemic genera in a single clade and suggest that Central America played a critical role in the early biogeographical history of the group. The large, predominantly Mexican genus Pseudoeurycea is paraphyletic, and analyses of the nuclear data place two lineages of Pseudoeurycea as the sister group of Bolitoglossa. Our phylogeny reveals extensive homoplasy in morphological characters, which may be the result of truncation or alteration of a shared developmental trajectory. We used our phylogenetic results to revise the taxonomy of the genus Pseudoeurycea. © 2015 The Linnean Society of London

Two extremely rare new species of fossorial salamanders of the genusOedipina(Plethodontidae) from northwestern Ecuador

“…Plethodontid salamanders from the American tropics are among the most diverse amphibians, with their radiation concentrated in Middle America (Rovito et al, 2015;Wake, 1987). With the exception of a few members of the family Salamandridae in southeast Asia, only plethodontids occupy tropical environments.…”

Persistent Plethodontid Themes: Species, Phylogenies, and Biogeography

“…He recognized the diversity (many species and even clades have since been discovered) but stated, ''The extremes are quite different but there are many connecting links' ' (1926: 32). The subsequent subdivision of this genus into many genera has had a positive effect (for the latest classification, see Rovito et al 2015). However, I argue against going further for bolitoglossines in the absence of new discoveries.…”

“…I use adaptive radiation in a very general sense, unrestricted by time or taxonomic depth. Examples include the Ensatina complex, what we have long recognized as the ''desmognathines,'' and the genus Thorius and other tropical salamanders (bolitoglossines; Rovito et al 2015). Adaptive radiations of this sort are active and expanding.…”

“…All relevant molecular analyses (cited above) find Bolitoglossini (now restricted to the tropical taxa) to be a clade with Batrachoseps as the sister taxon. Only recently have relationships within Bolitoglossini been nearly resolved (Rovito et al 2015). That study sampled 58-63 taxa (all genera and major clades) for three nuclear genes and a portion of the mitochondrial genome.…”

Persistent Plethodontid Themes: Species, Phylogenies, and Biogeography

“…The latter authors estimated the age of the bolitoglossine clade at 47 (41À53) mya, or mid-Eocene. Rovito et al (2015) estimated the date of the start of divergence within the clade at about 42 mya.…”