The Anatolio‐Balkan phylogeographic fault: a snapshot from the genus Isophya (Orthoptera, Tettigoniidae)

Abstract

Due to active tectonic evolution of the Aegean Area during Miocene and Pleistocene, the Balkans and Anatolia have repeatedly connected and disconnected causing isolation and secondary contact of populations along the present Dardanelles – Sea of Marmara – Bosphorus waterway. This has led to an outstandingly rich fauna and a reticulate biogeography in the area. A typical example is Orthoptera having here possibly highest diversity within the Western Palaearctic. With the present study, we concentrate on the bush‐cricket genus Isophya, which is characteristic with a large share of endemics in the Balkans and Anatolia. We aim to understand when and how the isolation of marine or other barriers in the region of the Turkish Straits System influenced the evolution of the morpho‐acoustic groups of species found on both sides of the strait. For this purpose, sequences of two mitochondrial (COI and ND2) and two nuclear (ITS1 and ITS2) markers were obtained and used for phylogenetic reconstructions, time estimations for lineage divergence and automatic species delineation (statistical parsimony, GMYC, ABGD) tests. The phylogenetic analyses did not support all the existing morphogroups and was in favour of a geographical subdivision for the young lineages. Automatic species delineation tests confirmed most of the present morpho‐acoustic species and suggested further cryptic species, at the same time unifying some phenetic species. Time estimation analyses suggested time to most recent common ancestor of the genus as 8.28 Ma corresponding to the Late Tortonian. As a result of the study, we reached to the following conclusions: (i) most of the studied phenetic species are monophyletic, but some earlier suggested morpho‐species groups are not, (ii) three main episodes dominate the evolutionary history of Isophya (7.32–5.84 Myr in the Messinian, 2.2–2.5 Myr in the beginning of the Pleistocene and at around 0.75 Ma corresponding to the end of the Mid‐Pleistocene transition), all of which well correlate with episodes of existing terrestrial connections between Anatolia and the Balkans, and (iii) there are several faunal exchanges in both directions between Anatolia and the Balkans.

Acoustic signals of the bush-crickets Isophya (Orthoptera: Phaneropteridae) from Eastern Europe, Caucasus and adjacent territories

“…studied by us belong to several groups (Warchalowska-Sliwa et al, 2008;Chobanov et al, 2013Chobanov et al, , 2017. Species producing songs of the fi rst type mainly belong to the I. speciosa and I. schneideri species groups.…”

“…Recent work based on morphological, acoustical and molecular-genetic characters and data on the distributions of Isophya spp. from Anatolia and the Balkans (Chobanov et al, 2017), elucidates some factors that could affect the evolution of the species studied. As a result of this, there are some contradictions between the phenetic grouping and the phylogeny based on mitochondrial and nuclear markers.…”

“…Up to ten species groups are currently distinguished in this genus: I. costata, I. kraussii, I. major, I. modesta, I. pyrenaea, I. rectipennis, I. schneideri, I. speciosa, I. straubei and I. zernovi (Warchalowska-Sliwa et al, 2008;Unal, 2010;Chobanov et al, 2013Chobanov et al, , 2017. Several species are known as pests of fruit crops, vine, tobacco etc.…”

“…Bey-Bienko (1954) notes that the morphological characters are very variable. The taxonomic position of I. schneideri remains a subject of discussion (Sevgili et al, 2012;Chobanov et al, 2017).…”

“…Since then acoustic signals of many western European species have been carefully studied (e.g. Heller, 1984Heller, , 1988Heller, , 1990Ingrisch, 1991;Ragge & Reynolds, 1998;Heller et al, 2004;Warchalowska-Sliwa et al, 2008;Iorgu & Iorgu, 2012;Chobanov et al, 2013Chobanov et al, , 2017, but songs of species from southeastern Europe, Caucasus and Transcaucasia remain poorly known; sound signals are preliminarily described for only a few phaneropterids from these regions (Zhantiev & Dubrovin, 1977;Zhantiev & Korsunovskaya, 1986, 1990, 2015.…”