Recent evolutionary history of Lost World endemics: population genetics, species delimitation, and phylogeography of sky-island treefrogs.

The tepuis of South America are massive flattop mountains with cliffs up to 1000m and summits up to 3100m. Tepuis hold enormous endemicity levels, but little is known about the origins of the endemic flora and fauna. Recently diverged lineages offer the possibility of understanding the origins of summit endemicity by examining population dynamics and dispersal. We examine species delimitation, clade relationships, and demographic patterns of three recently diverged lineages of Tepuihyla, an endemic treefrog clade. These three lineages represent two currently recognized species, T. edelcae and T. rodriguezi. Given the low divergences in both nuclear and mitochondrial genes among lineages, we find unexpectedly high numbers of unique nuclear haplotypes and moderate levels of lineage sorting. We also find support from multiple analyses for a cryptic, undescribed summit species within T. edelcae. We suggest that the genetic and distribution patterns of the four most recently diverged Tepuihyla lineages support a concurrent speciation event during the Pliocene, and suggest a biogeographic hypothesis in which a widespread climatic change made mid- and low-elevation habitat unsuitable for the common ancestor within the timeframe of their divergence.

Genetic divergence is more tightly related to call variation than landscape features in the Amazonian frogs Physalaemus petersi and P. freibergi.

Behavioural isolation from divergence in male advertisement calls and female preferences is hypothesized to cause genetic divergence and speciation in the Amazonian frogs Physalaemus petersi and P. freibergi, yet the importance of call variation and landscape features in genetic divergence is unresolved. We tested for correlations between genetic divergence at microsatellite loci and (1) call variables; and (2) landscape variables among 10 populations of these frogs. Genetic divergence was not correlated with geographical distance, rivers or elevation. There was a strong positive relationship, however, between genetic divergence and inter-population differences in one call variable, whine dominant frequency. Effective population sizes varied among sites (range = 15-846) and were often small, suggesting that genetic drift could influence call evolution. Evidence for fine-scale genetic structure within sites was also found. Our results support the hypothesis that behavioural isolation from divergence in male calls and female preferences causes genetic divergence and speciation.

An upper eocene frog from the dominican republic and its implication for Caribbean biogeography.

A frog of the leptodactylid genus Eleutherodactylus is reported from Eocene amber found in the Dominican Republic. It is the first described amphibian fossil in amber, and the oldest complete lissamphibian fossil from Mesoamerica (Central America and Mexico). Dating of the amber matrix indicates that by the end of the Eocene a diverse fauna was present in the Antilles, much earlier than has generally been proposed. The presence of this and other amber fossils from this same age suggests that Tertiary patterns of landmass movements were significant in determining the present distribution of species.

Ancient phylogeographic divergence in southeastern Australia among populations of the widespread common froglet, Crinia signifera.

Geographic patterns of species diversity in southeast Australia have been attributed to changes in Pleistocene climate, but related phylogeographic patterns and processes are relatively understudied. 12S and 16S mitochondrial DNA sequences in Crinia signifera populations were used to infer historical patterns and processes in southeast Australia. Phylogenetic analysis identified three geographically restricted ancient lineages and several geographically restricted sub-clades. Present-day features that may prevent gene flow are absent between these geographic regions. Divergence among the three lineages corresponds to a late Miocene origin, approximately 9 million years ago (mya). The geographic breaks among the lineages are consistent with Miocene-Pliocene uplift in the Great Dividing Range and elevated sea levels in East Gippsland. Divergence among sub-clades in Victoria and South Australia is estimated to be within the early Pliocene, whereas sub-clades in New South Wales are estimated to have diverged near the Plio-Pleistocene boundary, approximately 2 mya. Geographic limits of sub-clades are consistent with geographic variation in advertisement calls, but are inconsistent with phylogeographic limits previously identified in other southeastern species.

Phylogeny of frogs of the Physalaemus pustulosus species group, with an examination of data incongruence.

Characters derived from advertisement calls, morphology, allozymes, and the sequences of the small subunit of the mitochondrial ribosomal gene (12S) and the cytochrome oxidase I (COI) mitochondrial gene were used to estimate the phylogeny of frogs of the Physalaemus pustulosus group (Leptodactylidae). The combinability of these data partitions was assessed in several ways: measures of phylogenetic signal, character support for trees, congruence of tree topologies, compatibility of data partitions with suboptimal trees, and homogeneity of data partitions. Combined parsimony analysis of all data equally weighted yielded the same tree as the 12S partition analyzed under parsimony and maximum likelihood. The COI, allozyme, and morphology partitions were generally congruent and compatible with the tree derived from combined data. The call data were significantly different from all other partitions, whether considered in terms of tree topology alone, partition homogeneity, or compatibility of data with trees derived from other partitions. The lack of effect of the call data on the topology of the combined tree is probably due to the small number of call characters. The general incongruence of the call data with other data partitions is consistent with the idea that the advertisement calls of this group of frogs are under strong sexual selection.