Ancient connections among the European rivers and watersheds revealed from the evolutionary history of the genus Telestes (Actinopterygii; Cypriniformes)

Abstract

In order to better understand the complex geologic history of the Mediterranean area, we have analysed evolutionary history, phylogeographic structure and molecular diversity of freshwater fishes belonging to the genus Telestes. As primary freshwater fishes distributed largely in the Mediterranean basin, this genus represents a suitable model system for investigating the historical biogeography of freshwater drainage systems in southern Europe. In this investigation we have included samples representing all Telestes species and based our analyses on one mitochondrial and one nuclear gene. We have investigated phylogenetic structure inside the genus Telestes, estimated divergence times, reconstructed ancestral distribution ranges and described intraspecific molecular diversity. Diversification of Telestes started in the Early Miocene, when the ancestors of T. souffia, lineage comprising T. croaticus and T. fontinalis, and the one comprising T. pleurobipunctatus and T. beoticus got isolated. The remaining species are genetically more closely related and form a common cluster in the recovered phylogenetic trees. Complex geological history of southern Europe, including formation of continental bridges, fragmentation of landmass, closing of the sea corridor, local tectonic activities, led to complicated biogeographical pattern of this genus, caused by multiple colonization events and passovers between ancient rivers and water basins. Especially pronounced diversity of Telestes found in the Adriatic watershed in Croatia and Bosnia and Herzegovina is a consequence of a triple colonization of this area by different lineages, which led to an existence of genetically distinct species in neighboring areas. Significant intraspecific structuring is present in T. souffia, T. muticellus, T. croaticus and T. pleurobipunctatus. Besides in well-structured species, elevated levels of genetic polymorphism were found inside T. turskyi and T. ukliva, as a consequence of their old origin and unconstrained evolutionary history.

Fig 1. Map of the investigated area with marked sampling localities.

1- Lergue, 2-Hérault, 3-Argens, 4-Var, 5-Soča, 6-Gradaščica, 7-Jevnica, 8-Bregana, 9-Roya, 10-Bevera, 11-Staffora, 12-Po, 13-Arno, 14-Tiber, 15-Volturno, 16-Jasenak field, 17-Sušik, 18-Studenac, 19-Šmit lake, 20-Jadova, 21-Ričica, 22-Suvaja, 23-Krbava, 24-Čikola, 25-Vinelić, 26-Cetina, 27-Gatačko field, 28-Dabarsko field, 29-Konavle, 30-Zeta, 31-Morača, 32-Cijevna, 33-Kalamas, 34-Pinios, 35-Pavllo, 36-Louros, 37-Acheloos, 38-Evinos, 39-Alfios, 40-Kifissos. Different colors represent ranges as used for S-DIVA analysis.

Fig 2. Phylogenetic tree of cyt b sequences based on Bayesian (BAY) and Maximum parsimony (MP) inferences.

Numbers at nodes represent Bayesian posterior probabilities and MP branch support.

Fig 3. Phylogenetic tree of RAG1 sequences based on Bayesian (BAY) and Maximum parsimony (MP) inferences.

Numbers at nodes represent Bayesian posterior probabilities and MP branch support. Asterisk denotes one allele from the TEEV7 sample, which belongs to Squalius sp.

Fig 4. Median-joining network of nuclear haplotypes.

Black circles represent median vectors. The number of mutational steps is displayed by the branches if higher than 2. Haplotype clusters are marked with roman numbers and haplotypes belonging to different species are presented with different colors. The arrow marks one allele from the TEEV7 sample, which belongs to Squalius sp.

Fig 5. Divergence time estimations inside the genus Telestes based on cyt b sequences.

Timing of the splitting events is presented by mean values and the 95% credibility range (in brackets), in million years ago. Numbers in square brackets are posterior probabilities (*-posterior probability = 1).

Fig 6. Divergence time and ancestral geographic ranges estimations inside the genus Telestes based on the concatenated data set (cyt b and RAG1).

Timing of the splitting events is presented by mean values and the 95% credibility range (in brackets), in million years ago. Numbers in square brackets are posterior probabilities (*-posterior probability = 1). Ranges—A: rivers in the NW part of the Mediterranean area (Lergue, Hérault, Argens, Var, Roya, Bevera, Stafora, Po), B: Apennine Peninsula (Arno, Tiber, Volturno), C: rivers in northern Dinarids belonging to the Black Sea drainage (Soča, Gradašćica, Jevnica, Bregana, Jasenak field, Sušik, Studenac, Šmit lake), D: karstic rivers in middle Dinarids (Jadova, Ričica, Suvaja, Krbava, Čikola, Vinelić, Cetina, Gatačko field, Dabarsko filed, Konavle), E: Adriatic rivers in Monte Negro (Zeta, Morača, Cijevna), F: rivers of southern Albania and Greece (Pavllo, Kalamas, Louros, Acheloos, Evinos, Alfios, Kifissos).

Fig 7. Colonization routes of the Telestes lineages, based on the proposed evolutionary scenario.

*—Telestes ancestor in 7a and 7b, ancestor of T.croaticus/T. fontinalis in 7c and 7d; #—ancestor of T. souffia; x–ancestor of the species cluster (T. metohiensis/T. dabar/T. miloradi/T. muticellus/T. montenigrinus/T. ukliva/T. turskyi/T. karsticus/T. polylepis); o–ancestor of T. pleurobipunctatus/T. beoticus.