Overlapping patterns of morphometric and genetic differentiation in the Mediterranean goby Pomatoschistus tortonesei Miller, 1968 (Perciformes, Gobiidae) in Tunisian lagoons
Abstract. The genetic and morphological variations of Pomatoschistus tortonesei Miller, 1968 were studied in samples collected from three Tunisian lagoons. The morphological analysis included 18 morphometric measurements and was based on linear discriminant analysis (LDA), whereas the genetic analysis was based on the 16S-rRNA and COI mitochondrial genes. Both analyses differentiated the populations and demonstrated consistently a well-supported differentiation between the western Mediterranean samples (Bizerta and Tunis South lagoons) and the eastern Mediterranean sample (El Bibane lagoon). The observed differentiation could be explained in terms of the geographic isolation of the various …
Genetic architecture of the marbled goby Pomatoschistus marmoratus (Perciformes, Gobiidae) in the Mediterranean Sea
The marbled goby Pomatoschistus marmoratus, a species inhabiting coastal Mediterranean lagoons, has been studied by measuring its mitochondrial DNA variation. This analysis revealed a Mediterranean west vs east split and, subsequently, an eastern differentiation among the Libyan–Tunisian Gulf, the Adriatic Sea and the Aegean Sea. The high cohesion between the samples collected in the vast area of western Mediterranean contrasts with the genetic mosaic of the more sub-structured eastern Mediterranean. This western homogeneity can not yet be fully explained even if a human-mediated migratory flow, due to a maritime traffic, has been posited. The pattern in the eastern basin revealed a genetic…
A study on Pomatoschistus tortonesei Miller 1968 (Perciformes, Gobiidae) reveals the Siculo-Tunisian Strait (STS) as a breakpoint to gene flow in the Mediterranean basin.
The current genetic structure of P. tortonesei, exclusively inhabiting lagoons, may reflect a Plio-Pleistocene colonisation of an ancestor line which has undergone phases of population decline and expansion, following alternate cooling phases. Regarding the calculation of divergence time, it has been estimated that P. tortonesei seems to be the most recent species within the Pomatoschistus genus. It appears also that the discrepancy of P. tortonesei into two distinct phyletic lineages occurred 0.1 Mya. Recurring shifts in sea level and sea surface temperatures of Mediterranean Sea caused the desiccation of shallower lagoons and the consequent bottleneck phenomena of the brackish populations…