Phylogeography and evolution of the triplefin Tripterygion delaisi (Pisces, Blennioidei)

Abstract

The genus Tripterygion (Risso 1826) is restricted to the eastern Atlantic and the Mediterranean, and comprises only three species. T. melanuros and T. tripteronotus are essentially endemic to the Mediterranean, while Tripterygion delaisi occurs in the Atlantic and in the Mediterranean. Two subspecies of T. delaisi have been described (T. d. xanthosoma in the Mediterranean and T. d. delaisi in the Atlantic). Several scenarios have been proposed for the evolution of T. delaisi subspecies, but so far its subspeciation process is not clear. In this study we present a population survey of T. delaisi including specimens from the two recognized subspecies. We combined a phylogeographic approach with estimates of the direction of migration (between the Atlantic and the Mediterranean) and of the coalescence time of the two subspecies, using polymorphic mitochondrial and nuclear genes. The results of this study clearly support the existence of two Tripterygion delaisi clades, one in the eastern Atlantic islands and another in the Atlantic coasts of Europe and in the Mediterranean. Historical migration between the islands and Western Europe plus Mediterranean was restricted, and showed a westbound trend, with a higher number of migrants going from the Western Europe plus Mediterranean into the islands. We estimated the time of coalescence of both groups of T. delaisi to be more recent than the onset of Pleistocene glaciations (1.7 Mya). Our results are consistent with previous hypothesis that consider successive dispersal events of a Tripterygion ancestor from the western African coast colonizing the Atlantic islands and the Mediterranean, promoting the evolutionary divergence between these areas.

Phylogeography and demography of the Blenniid Parablennius parvicornis and its sister species P. sanguinolentus from the northeastern Atlantic Ocean and the western Mediterranean Sea

“…Santos et al (1995a) suggested that such a decrease would have been enough to promote the local disappearance of warm water species such as P. parvicornis from the Azores. The less affected tropical western coast of Africa, the archipelago of Madeira, the westernmost Canary islands and some regions of the Mediterranean have been shown to act as refugia for species that were not able to survive the cold phases in the northern Atlantic locations (Domingues et al, , 2007a. Our findings support this hypothesis.…”

“…Almada et al (2001) argued that the warmer water fish of the Atlanto-Mediterranean area survived in two distinct glacial refugia which acted as sources of post-glacial colonization: one in the west coast of Tropical/Subtropical Africa and Madeira, from which fish reached the Azores, and another inside the Mediterranean, from which the northeastern Atlantic waters adjacent to the Mediterranean entrance were colonized during the interglacials. These ideas have been supported by molecular studies on species like the pomacentrid Chromis limbata and the blenniid Tripterygion delaisi (Domingues et al, 2007a).…”

“…Studies on the phylogeography and historic demography of the marine fish fauna of the northeastern Atlantic Ocean and the Mediterranean Sea have demonstrated the impact of the Pleistocene glaciations on their populations (Domingues et al, , 2007aStefanni et al, 2006). Estimates of sea surface temperatures (SST) of the northeastern Atlantic over the last 280 Kyr showed a clear glacial/interglacial evolution and a steep north-south SST gradient between 37 and 45°N during the last glacial period (Calvo et al, 2001).…”

“…Effects of the cooling events of the Mediterranean have also been identified by the molecular analysis of C. chromis (Domingues et al, 2005), T. delaisi (Domingues et al, 2007a) and Diplodus sargus (Bargelloni et al, 2005;Domingues et al, 2007b).…”

Tropical fishes in a temperate sea: evolution of the wrasse Thalassoma pavo and the parrotfish Sparisoma cretense in the Mediterranean and the adjacent Macaronesian and Cape Verde Archipelagos

“…Distribution ranges of T. pavo and S. cretense reXect a clear preference for warm waters. Some warm water species such as Chromis chromis C. limbata and Tripterygion delaisi (Domingues et al 2006(Domingues et al , 2007, have been suggested to have survived the cold periods in warmer regions like Madeira, the tropical African coast and the southern Mediterranean, where the climatic conditions did not change signiWcantly during the Pleistocene (Thiede 1978;Crowley 1981). Indeed, Mediterranean populations of T. pavo and S. cretense show high levels of genetic diversity even in the eastern basin, pointing to an ancient colonization of this sea.…”