Fig 1.
Locality samples and distribution range of S. keadicus and S. peloponensis according to [37].
Table 1.
Specimens used in molecular and morphological analyses and their voucher numbers.
GenBank accession numbers for all analysed genes and labels in phylogenetic trees. All these specimens except those marked with an * symbol, proceeding from GenBank database, have been used in morphological analyses.
Fig 2.
Morphometric variables measured in the Squalius populations analysed.
Fig 3.
Phylogenetic tree based on the MT-CYB gene.
Bootstrap values for ML analysis below branches. Posterior probability values for Bayesian inference above branches.
Fig 4.
Phylogenetic tree based on the nuclear S7 gene.
Bootstrap values for ML analysis below branches. Posterior probability values for Bayesian inference above branches.
Fig 5.
Phylogenetic tree based on the nuclear RAG1 gene.
Bootstrap values for ML analysis below branches. Posterior probability values for Bayesian inference above branches.
Fig 6.
Phylogenetic tree based on the phased nuclear RAG1 (A) and S7 (B) genes. Posterior probability values for Bayesian inference above branches. Blue = Alfios (S. peloponensis); Red = Evrotas (S. keadicus); Green = S. keadicus-like mitochondrial (Miras and Pamissos populations).
Table 2.
Uncorrected-p genetic distances (%) between (below diagonal) and within (in diagonal) populations for the three genes analysed.
Fig 7.
Chronogram obtained for the MT-CYB gene for several Squalius species.
Divergence time estimates and their HPD 95% confidence intervals, in Ma, for the main cladogenetic events between Squalius species above branches. Posterior probability values of Bayesian inference below branches (** indicates posterior probability = 1). Black arrow highlights the divergence time estimated for the separation of mitochondrial lineages of S. keadicus and the introgressed populations. Red asterisk indicates the position of fossil ages used to calibrate the molecular clock.
Fig 8.
Specimens of the four analysed populations.
Voucher specimen numbers: Squalius peloponensis from Alfios River (MNCN_ICTIO 94.982); Squalius peloponensis from Pamissos River (NMP PV6 F1227); Squalius peloponensis from Miras River (MNCN_ICTIO 94.747); Squalius keadicus from Evrotas River (MNCN_ICTIO 123.875).
Fig 9.
Canonical Variate Analysis of the four Squalius populations.
A) Morphometric measurements. B) Meristic measurements. Red: Evrotas population (S. keadicus), blue: Alfios population (S. peloponensis); light blue: Miras population (S. peloponensis); green: Pamissos population (S. peloponensis).
Table 3.
Kruskal-Wallis test and non-parametric Mann-Whitney pairwise post hoc comparisons for all populations.
Ev = Evrotas, Al = Alfios, Pa = Pamissos, Mi = Miras, Significant differences p < 0.01. Acronyms of variables are defined in the Material and Methods section.
Table 4.
Canonical Variate Analysis values for the first three canonical axes of analyses of morphometric and meristic variables.
Acronyms of variables are defined in the Material and Method section.
Fig 10.
Box-plot of meristic variables.
The 25–75 percent quartiles are drawn inside the box. Short horizontal lines represent minimal and maximal values.
Table 5.
Significant proportions (%) relative to standard length (SL) or head length (HL) of several morphometric variables differentiating the four analysed populations.
Fig 11.
Hypothetical biogeographical scenarios explaining the mitochondrial capture event from Squalius keadicus to Squalius peloponensis.
Each rectangle symbolizes a hypothetical individual within the analysed population. The two squares within each rectangle symbolize the mitochondrial and the nuclear genome of this hypothetical individual in the population. Colours indicate populations: Blue = S. peloponensis lineage; Red = S. keadicus lineage; Green = S. keadicus-like mitochondrial lineage (Miras and Pamissos populations).