Data from: Phylogenomic inference and demographic model selection suggest peripatric separation of the cryptic steppe ant species Plagiolepis pyrenaica stat. rev.

The ant Plagiolepis taurica Santschi, 1920 (Hymenoptera, Formicidae) is a
typical species of the Eurasian steppes, a large grassland-dominated biome
that stretches continuously from Central Asia to Eastern Europe and is
represented by disjunct outposts also in Central and Western Europe. The
extent of this biome has been influenced by the Pleistocene climate, and
steppes expanded recurrently during cold stages and contracted in warm
stages. Consequently, stenotopic steppe species such as P. taurica
repeatedly went through periods of demographic expansion and severe
isolation. Here, we explore the impact of these dynamics on the genetic
diversification within P. taurica. Delimitation of P. taurica from other
Plagiolepis species has been unclear since its initial description, which
raised questions on both its classification and its spatiotemporal
diversification early on. We re‐evaluate species limits and explore
underlying mechanisms driving speciation by using an integrative approach
based on genomic and morphometric data. We found large intraspecific
divergence within P. taurica and resolved geographically coherent western
and eastern genetic groups, which likewise differed morphologically. A
morphometric survey of type material showed that Plagiolepis from the
western group were more similar to P. barbara pyrenaica Emery, 1921 than
to P. taurica; we thus lift the former from synonymy and establish it as
separate species, P. pyrenaica stat. rev. Explicit evolutionary model
testing based on genomic data supported a peripatric speciation for the
species pair, probably as a consequence of steppe contraction and
isolation during the mid‐Pleistocene. We speculate that this scenario
could be exemplary for many stenotopic steppe species, given the
emphasized dynamics of Eurasian steppes.