Genome-wide DNA and phenotypic information supports recent colonization of South American grasslands by Correndera Pipit (Aves, Motacillidae)

摘要

Anthus correndera has a wide distribution in southern South America with several subspecies assigned to the taxon. We take an integrative approach, analysing genome-wide single-nucleotide polymorphism (SNP) data collected using ddRAD sequencing, songs and linear morphological data, to evaluate the evolutionary history of A. correndera and divergence of each subspecies. The final genomic data set of 11,467 SNPs for 40 individuals supports a primary divergence of two main lineages: one in the Andean highlands and another in the lowlands. Estimated divergence times suggest the Andean and lowland groups diverged around 135.5 to 99 thousand years ago (Ka), whereas divergence among populations within each group was much more recent, ranging from 54.7 Ka among the Andean populations to as recent as 20.6 Ka among the lowland populations. Analyses of territorial songs showed slight differences between all operational taxonomic units; however, morphological differences were apparent only between geographically distant populations (i.e. Puna vs. South Georgia). Based on multiple lines of evidence, we propose to reduce the number of subspecies within the correndera complex to three: A. c. calcaratus on the Andean Altiplano (treating A. c. catamarcae as a junior synonym), A. c. correndera in the lowlands (treating A. c. chilensis and A. c. grayi as junior synonyms), and A. c. antarcticus on South Georgia.