Abstract
The Aegean archipelago is among the largest on Earth with astonishing biodiversity within Europe. Its territory underwent a massive geotectonic transformation in Neogene that resulted in multitude of changes in land-sea configuration and disintegrated the formerly united Aegean land to a complicated mainland-archipelago system. Therefore, it represents an excellent laboratory for studying evolution of terrestrial fauna. In the present study, we use a model group of flightless bush crickets with annual reproduction cycle—Poecilimon jonicus species group—to trace correlation of lineage diversification with the known paleogeographic events in the Aegean area. The group belongs to the hyperdiverse genus Poecilimon and has a disjunct distribution along the Hellenic arc from southwestern Anatolia through Crete to the western Balkans and the Apennines. To test our hypothesis, we inferred phylogenetic relationships of the P. jonicus group sensu lato using a nuclear fragment covering two spacers of the ribosomal cistron (ITS1 + ITS2). To study intra-group phylogeny, we compared mitochondrial phylogenies based on two matrices—(1) a concatenated ND2 and COI dataset of 1656 bp and (2) a 16S rRNA + 12S rRNA dataset of 1835 bp. As a second step, we estimated divergence times applying Bayesian approach with BEAST and a relative rate framework with RelTime on the mitochondrial matrices. We compare trees calibrated based on evolutionary rates and tectonic events and discuss radiation scenarios in concordance with known paleogeographic events in the Aegean area. Our results revealed robust phylogeny of the Poecilimon jonicus group and confirmed a strong link between its evolution and the Aegean paleogeography. The phylogenetic relationships of the group supported reconsideration of its systematics.
Highlights
Archipelagoes provide rich and comparatively simple experimental sets for studying the evolution of terrestrial organisms due to their small size, isolated biotas, and possibilities for a more precise dating of vicariant events in comparison with mainland systems (Shaw and Gillespie 2016)
Re-flooding of the Aegean by the beginning of the Pliocene strongly affected the early evolution of terrestrial biota in this area, while later (Plio-Pleistocene) vicariant and dispersal events were ruled by smaller-scale land-sea configuration changes due to climatic or paleogeographic processes, mostly within the areas separated by the three main Aegean basins and the so-called mid-Aegean trench
The main objectives of the present study are to, first, reconstruct phylogenetic relationships of P. jonicus group sensu lato and consider its systematics in the light of new knowledge and, second, estimate divergence times for the group members and test if radiation steps in their evolutionary history correlate with the known paleogeographic events in the Aegean area
Summary
Archipelagoes provide rich and comparatively simple experimental sets for studying the evolution of terrestrial organisms due to their small size, isolated biotas, and possibilities for a more precise dating of vicariant events in comparison with mainland systems (Shaw and Gillespie 2016). In late Miocene, tectonic events formed basins and grabens, which were filled by the Tortonian transgression of the Mediterranean Sea, resulting in the first formation of the Aegean Sea that established a connection with the Euxinian (Pontian) Basin (Meulenkamp 1977; Dermitzakis 1990; Steininger and Rögl 1984; Jolivet et al 2006; Popov et al 2004, 2010). Re-flooding of the Aegean by the beginning of the Pliocene strongly affected the early evolution of terrestrial biota in this area, while later (Plio-Pleistocene) vicariant and dispersal events were ruled by smaller-scale land-sea configuration changes due to climatic or paleogeographic processes, mostly within the areas separated by the three main Aegean basins and the so-called mid-Aegean trench (reviewed by Poulakakis et al 2014)
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