# Phylogeographic Insights into Pipistrellus Species from Türkiye: Diversity, Divergence, and Regional Lineage Structure

## TL;DR

This study uses genetic data to reveal hidden diversity and evolutionary patterns in Pipistrellus bats in Türkiye, showing the region's role as a key area for bat evolution and conservation.

## Contribution

The study provides new phylogeographic insights into cryptic Pipistrellus species in Türkiye, revealing unrecognized lineages and the evolutionary role of Anatolia.

## Key findings

- Morphological identification of Pipistrellus species in Türkiye is unreliable, with molecular data showing misidentifications.
- Türkiye serves as both a refugium and a contact zone for bat lineages, including a previously unrecognized lineage of Nathusius’ pipistrelle.
- The Anatolian Diagonal acts as a barrier and corridor, separating and overlapping Eastern and Western lineages of P. pipistrellus.

## Abstract

Bats are important mammals that contribute to natural balance by consuming insects and serving as indicators of healthy ecosystems. In Türkiye, four closely related species of the genus Pipistrellus are found, yet they are extremely difficult to identify based on external appearance alone. This study investigated their genetic diversity and evolutionary history using mitochondrial Cytb sequences collected from a wide range of regions. The results showed that external features often lead to misidentification, especially between the common pipistrelle and the soprano pipistrelle, highlighting the importance of molecular data for reliable classification. We also discovered that Türkiye plays a dual role in bat evolution, serving both as a refugium for unique lineages and as a contact zone where different lineages meet. Distinct lineages of the common pipistrelle and Kuhl’s pipistrelle were found to overlap within Anatolia, and a previously unrecognized lineage of Nathusius’ pipistrelle was detected in southwestern Türkiye. In Pipistrellus pipistrellus, the Anatolian Diagonal separates eastern and western lineages while still allowing their overlap, acting as both barrier and corridor. These findings emphasize the value of Türkiye as both a refugium and a crossroads for bat diversity, providing knowledge essential for conservation and ecosystem protection.

This study investigates the phylogenetic relationships, genetic diversity, and biogeographic structure of Pipistrellus species in Türkiye using mitochondrial cytochrome b (Cytb) sequences from 156 specimens collected across 26 localities. Our primary aim was to clarify taxonomic boundaries of morphologically cryptic species and elucidate the evolutionary role of Anatolia in the Western Palearctic. Analyses strongly confirmed that molecular data are mandatory for defining taxonomic boundaries. Crucially, all individuals morphologically identified as P. pygmaeus were genetically determined to be P. pipistrellus, highlighting the inadequacy of external traits for cryptic species. We resolved deep intraspecific divergence across the genus. In P. pipistrellus, two major lineages (Eastern and Western) were identified, partially separated by the Anatolian Diagonal. Their co-occurrence in multiple localities confirms Anatolia’s function as a secondary contact zone. Similarly, P. kuhlii populations represent a transition zone where two distinct lineages, one of Asiatic origin (P. k. lepidus) and one Mediterranean-Levantine (P. k. kuhlii), meet. Furthermore, while P. nathusii is largely associated with migratory European lineages; a genetically distinct, potentially resident lineage was revealed in southwestern Anatolia. Divergence time estimations indicate that this diversification was shaped by major climatic events from the Miocene to the Pleistocene. This study demonstrates that Anatolia is more than just a geographic bridge; it is a dynamic center of evolution, functioning critically as both a glacial refugium and a secondary contact zone for Palearctic bat fauna.