Systematics of the Pristimantis chloronotus species group (Anura, Craugastoridae) with insights into their historic biogeography

Abstract:

With 490 species, Pristimantis is the most speciose genus of vertebrates reaching its highest diversity along the slopes of the northern Andes. The processes that originated this spectacular diversity have been studied at the family level (i.e., a bottom up approach) with the caveat that taxon sampling has been sparse. Analyses based on extensive species sampling focused on small clades (i.e., top down sampling) are still missing. Herein we assess the phylogeny and taxonomic status of a clade of 20 species of Pristimantis from the eastern Andean slopes. Our analyses rely on three independent lines of evidence: external morphology, environmental data, and genetics. We obtained a phylogeny based on mitochondrial and nuclear genes (16S, ND1 and RAG1). To estimate the timing of the origin of contemporary species, we inferred a time-calibrated phylogeny with reconstruction of altitudinal ancestral areas. Based on our phylogeny we propose the recognition of the P. chloronotus species group. This clade, which is strongly supported, is composed by 15 formally described species (P. ardyae, P. chloronotus, P. colonensis, P. eriphus, P. hernandezi, P. huicundo, P. incanus, P. inusitatus, P. llanganati, P. lividus, P. ortizi, P. roni, P. supernatis, P. thymelensis, and P. yanezi), 4 confirmed candidate species, and 1 unconfirmed candidate species. Morphometric and environmental analyses show little differentiation among species in spite of considerable genetic divergence (uncorrected p-distances among species 3% ̶ 15% for 16S). Our analyses estimated the origin of the P. chloronotus species group in the Oligocene, when the elevation of the northern Andes was no more than half its modern altitude. The major events of diversification within the P. chloronotus species group coincide temporally with the major sequential bouts of Andean orogenesis in the Miocene-Pleistocene transition. Furthermore, the current allopatric distribution of sister lineages of the P. chloronotus species group suggest that the spatio-temporal diversification in this clade is causally linked to Andean uplift and palaeo-climate change through vicariance. Our results give insights in the evolutionary processes that generate diversity in the Tropical Andes, one of Earth’s biodiversity hotspots.

Año de publicación:

2017

Keywords:

• Tropical Andes
• Biología
• Craugastoridae
• Anura
• PRISTIMANTIS CHLORONOTUS

Fuente:

rraae