Abstract
Background. Calomera littoralis is a Palearctic species, widely distributed in Europe; inhabiting predominantly its Atlantic, Mediterranean and Black Sea coastlines.Methods. Its phylogeography on the Balkan Peninsula and on the north-western Black Sea coast was inferred using a 697 bp long portion of the mitochondrial COI gene, amplified from 169 individuals collected on 43 localities.Results. The results revealed two genetically divergent groups/lineages, the southern one inhabiting both the Balkan Peninsula and the Pontic Region and the northern one found exclusively in the Pontic Region. Species delimitation based on DNA barcoding gap suggested an interspecific level of divergence between these groups. Multivariate analysis of eight male and female morphometric traits detected no difference between the groups, implying they may represent cryptic species. The Bayesian time-calibrated reconstruction of phylogeny suggested that the lineages diverged ca. 2.3 Ma, in early Pleistocene.Discussion. The presence of the two genetically divergent groups results most likely from contemporary isolation of the Pontic basin from the Mediterranean that broke the continuous strip of coastal habitats inhabited by C. littoralis. Demographic analyses indicated that both lineages have been in demographic and spatial expansion since ca. 0.15 Ma. It coincides with the terminal stage of MIS-6, i.e., Wartanian/Saalian glaciation, and beginning of MIS-5e, i.e., Eemian interglacial, during which, due to eustatic sea level rise, a wide connection between Mediterranean and the Pontic basin was re-established. This, along with re-appearance of coastal habitats could initiate north-east expansion of the southern lineage and its secondary contact with the northern one. The isolation of the Pontic basin from the Mediterranean during the Weichselian glaciation most likely did not have any effect on their phylogeography.
Highlights
The Eastern Mediterranean, including the Pontic area, is recognised as one of the major biodiversity and endemism hot spots on a global scale, as well as a major glacial refugium in Europe (e.g., Myers et al, 2000; Kotlík, Bogutskaya & Ekmekçi, 2004; Blondel et al, 2010)
The mean Kimura 2-parameter (K2p) genetic distance between both groups of haplotypes is relatively high (0.039, SD 0.007). Both variants of the Automatic Barcode Gap Discovery (ABGD) analysis resulted in partitioning of the dataset into two OTUs, that may represent distinct operational taxonomic units—potential cryptic species or subspecies within Calomera littoralis in the studied area (Fig. 3A)
The level of divergence, 0.04 K2p distance, between the northern and the southern lineage is similar as those found between species of tiger beetles in other studies (e.g., Cardoso & Vogler, 2005; López-López, Abdul Aziz & Galián, 2015)
Summary
The Eastern Mediterranean, including the Pontic area, is recognised as one of the major biodiversity and endemism hot spots on a global scale, as well as a major glacial refugium in Europe (e.g., Myers et al, 2000; Kotlík, Bogutskaya & Ekmekçi, 2004; Blondel et al, 2010). There were at least twelve saline water intrusions from the Mediterranean Sea, and eight intrusions from the Caspian Lake to the Black Sea during the last 0.67 million years (Ma) i.e., in Pleistocene (Badertscher et al, 2011). They played an important role in modelling diversity and distribution patterns for numerous organisms, those inhabiting coastal ecosystems both in the Mediterranean and in the Pontic area. The presence of the two genetically divergent groups results most likely from contemporary isolation of the Pontic basin from the Mediterranean that broke the continuous strip of coastal habitats inhabited by C. littoralis. The isolation of the Pontic basin from the Mediterranean during the Weichselian glaciation most likely did not have any effect on their phylogeography
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
