Diversity and biogeography of Mediterranean freshwater blennies (Blenniidae, Salaria)

Aim: In the Mediterranean Biodiversity Hotspot freshwater fishes are key
biogeographical indicators while their habitats are vulnerable to ongoing
anthropogenic pressures. The freshwater blenny is a widespread endemic
taxon in this area. However, our understanding of the overall diversity of
specific populations and their phylogenetic relationships is sparse. Thus,
we aim to investigate the genetic diversity, infer relationships among
sampled populations related to major paleoenvironmental changes and
suggest insights for future research and conservation targets. Location:
Mediterranean Basin Methods: We studied
171 Salaria specimens from 51 rivers and lakes, and from
13 countries surrounding the Mediterranean Sea. For assessing the
phylogenetic relationships among different locations, we used mtDNA d-loop
and Intron S7 sequences. Furthermore, we inferred absolute divergence
times as well as demographic changes using secondary calibrations and
investigated the diversity within major lineages using haplotype networks
as well as several geographical and genetic clustering methods. Results:
We found eight well differentiated lineages, each of which being confined
to a particular geographic region. The onset of the freshwater blenny
radiation was dated around the Messinian salinity crisis. Further
differentiation happened during the Plio- and Pleistocene with signatures
of population expansion after the Last Glacial Maximum in some of the main
lineages. Main Conclusions: Due to their unusual widespread distribution,
the freshwater blennies represent an excellent model for studying
phylogeographic structure across the Mediterranean basin biodiversity
hotspot. The extant diversity and distribution of the
freshwater Salaria species mirrors