On the Taxonomic Status of Vorontsov’s Ground Squirrel (Spermophilus vorontsovi): Bioacoustic Analysis

Abstract

A comparative analysis has been conducted on acoustic alarm calls of Vorontsov’s ground squirrel (Spermophilus vorontsovi) and other species of red-cheeked ground squirrels within the erythrogenys group, which inhabit arid and semi-arid ecosystems. The absence of biphonation is a key distinguishing feature of S. vorontsovi and S. erythrogenys s. str. from other related species of the group. The alarm call of Vorontsov’s squirrel features a unique frequency modulation that differs slightly from the signal of the geographically close S. erythrogenys s. str., and this vocal difference correlates with the genetic proximity of the two species on a multilocus phylogenetic tree. The wide variation in alarm calls of the S. erythrogenys s. str. population in Eastern Kazakhstan could be due either to the presence of a large amount of pre-existing genetic variation from its ancestors (ancestral polymorphism) or to the limited gene flow from the left bank of the Irtysh River to the right bank. The divergence of signal traits among species within the erythrogenys group followed a model of geographic speciation, driven mainly by geographic barriers—specifically, large rivers.