Species formation and geographical range evolution in a genus of Central American cloud forest salamanders (Dendrotriton)

Abstract

Aim Montane Central America offers an ideal system for testing geographical hypotheses of species diversification. We examined how the complex geological history of Nuclear Central America has shaped the diversification of a genus of cloud‐forest‐inhabiting salamanders (Dendrotriton). We applied parametric models of geographical range evolution to determine the predominant mode of species formation within the genus and to test existing hypotheses of geographical species formation in the region. Location Montane cloud forests of Nuclear Central America. Methods We estimated a species tree for Dendrotriton using a multi‐locus DNA sequence data set and several coalescent methods, and performed molecular dating for divergence events within the genus. We then applied the species‐tree estimate to a likelihood‐based time‐stratified model of geographical range evolution, based on current species distributions and available geological information for Central America. Results Species trees from all methods contain two groups, one corresponding to species from the Sierra de los Cuchumatanes and the other containing all remaining species. In most cases, species formation within the genus involved an even division of the geographical range of the ancestral species between descendant species. The ancestor of extant Dendrotriton species was estimated to have occurred in either the Sierra de los Cuchumatanes or the Sierra Madre de Chiapas, and both of these areas appear to have been important for diversification within the genus. The single species found in the Quaternary‐age Guatemalan volcanic cordillera dispersed to the volcanoes from an older highland area. Main conclusions Models of geographical range evolution, when combined with robust species‐tree estimates, provide insight into the historical biogeography of taxa not available from phylogenies or distributional data alone. Vicariant species formation, rather than peripatric or gradient speciation, appears to have been the dominant process of diversification, with most divergence events occurring within or between ancient highland areas. The apparent dispersal of Dendrotriton to the Quaternary‐age volcanoes raises the possibility that the rich salamander community there is composed of species that dispersed from geologically older areas. The Motagua Valley appears not to have been as important in vicariant species formation within Dendrotriton as it is within other groups.

Genetic divergence of the Mesoamerican azure-crowned hummingbird (Amazilia cyanocephala, Trochilidae) across the Motagua-Polochic-Jocotán fault system

“…The uplifting of highlands on either side of the MPJ system fault area, and its further entrenchment producing isolation among populations, has generated divergence events in both lowland and highland species (but see Rovito et al. ,b). However, the timings of the divergence events associated with isolation by the MPJ barrier fall within the Miocene, Pliocene and Pleistocene.…”

Biogeography and evolution of Central American cloud forest salamanders (Caudata: Plethodontidae:Cryptotriton), with the description of a new species

“…Dendrotriton achieves highest species diversity in the Maya highlands, with only a single species found in the Guatemalan Volcanic Cordillera and another species found on the isolated Montaña de Santa Bárbara in the Chortís highlands. Biogeographic analyses with LAGRANGE indicated that Dendrotriton most likely arose in the Sierra Madre de Chiapas and/or the Sierra de los Cuchumatanes, both part of the Maya highlands, and subsequently dispersed to the Chortís highlands (Rovito et al ., ). Even though three species of Cryptotriton are found in the Maya highlands, two of these are from Alta Verapaz and are very close to the Motagua fault zone; no Cryptotriton is known from the Sierra de los Cuchumatanes or the Sierra Madre de Chiapas.…”

“…Chiropterotriton , as currently recognized, occurs exclusively to the west of the Isthmus of Tehuantepec and is not closely related to species it formerly contained that are now allocated to other genera ( Cryptotriton, Dendrotriton , and Nototriton ). Molecular studies using both allozymes (Good & Wake, ; Darda, ; Vásquez‐Almazán et al ., ) and DNA sequence data (García‐París & Wake, ; Parra‐Olea, ; Townsend et al ., ; Rovito et al ., ) have shed light on relationships within and between genera and supported the recognition of many new species.…”

“…McCranie & Rovito () did not recover strong support for interspecific relationships within Cryptotriton , and suggested that either more loci or the inclusion of additional, unsampled populations might help to resolve the phylogeny. Phylogenetic analysis of a similar cloud forest‐restricted clade, Dendrotriton , showed that species formed primarily in allopatry in geologically ancient areas of Nuclear Central America, illustrating the importance of the ancient highlands of the region in generating species diversity (Rovito et al ., ). Here, we estimate a phylogeny for Cryptotriton based on portions of two mitochondrial and four nuclear genes.…”

Bromeliad Selection by Two Salamander Species in a Harsh Environment

“…Interaction with bromeliads have been particularly important in the evolution and ecology of several Neotropical amphibian groups (e.g. [7], [12], [13], [14]). Several bromeliad traits are associated with the presence of anurans, including humidity, water availability and phytotelmata size [15]–[18].…”