Cryptic diversity in the Mediterranean Temnothorax lichtensteini species complex (Hymenoptera: Formicidae)

In this paper we provide insight into the cryptic diversity and biogeographic patterns of a widely distributed Mediterranean ant species, Temnothorax lichtensteini (Bondroit Annales de la Société Entomologique de France 87:1–174, 1918), based on evidence from multiple data sources. An exploratory analysis of morphometric data, combined with sequencing of a 652 bp fragment of the mitochondrial gene for
the cytochrome c oxidase subunit I (CO I), indicates the existence of three distinct lineages. Divergence of two recognised genetic lineages, Western and Eastern Mediterranean clusters, is not reliably supported by confirmatory analysis of morphological data. We hypothesise that this reflects incomplete speciation in separate glacial refugia and therefore discuss only biogeographic aspects of these two parapatric populations. However, the third, Peloponnese, lineage is divergent in both morphology and CO I sequences and its separation from the other two lineages is convincingly confirmed. For this lineage we assume a completed speciation and describe the taxon formally as Temnothorax laconicus sp.n., the sister species of T. lichtensteini.