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- Phylogeography and demographic history of Atherina presbyter (Pisces: Atherinidae) in the North-eastern Atlantic based on mitochondrial DNAPublication . Francisco, S. M.; Castilho, Rita; Soares, M.; Congiu, L.; Brito, A. B.; Vieira, M. N.; Almada, V. C.A fragment of the mitochondrial control region was used to assess phylogeographic patterns and historical demography of the sand-smelt Atherina presbyter in the North-eastern Atlantic, covering its geographical range. A striking result is the highly marked diVerentiation between the Canary Islands population and western European ones. A genetic structure among European populations of A. presbyter was revealed, with a pattern of isolation-by-distance or a gradient eVect at a scale of hundreds kilometres, an uncommon pattern likely related to the biological and life-history traits of the sand-smelt. The northern European populations present a much lower genetic diversity when compared to southern populations, which is consistent with a recent colonization from southern populations. The results showed signs of Pleistocene signatures, with the population age estimates for the European populations being clearly older than the Last Glacial Maximum (18,000 years bp). Nevertheless, paleotemperature reconstructions show that the sand-smelt could not have inhabited the western European shores during the last glacial phase.
- Genetic evidence fails to discriminate between Macroramphosus gracilis Lowe 1839 and Macroramphosus scolopax Linnaeus 1758 in Portuguese watersPublication . Robalo, J. I.; Sousa-Santos, C.; Cabral, H.; Castilho, Rita; Almada, V. C.Fish belonging to the genus Macroramphosus are distributed throughout the Atlantic, Indian and PaciWc oceans. Some authors consider this genus monotypic, Macroramphosus scolopax being the only valid species. Other authors consider (based on several morphological and ecological characters) that another species (Macroramphosus gracilis) exists and occurs frequently in sympatry with the Wrst one. Intermediate forms are also reported in literature. In this paper, using the mitochondrial control region and the nuclear Wrst S7 intron markers, we failed to Wnd genetic diVerences between individuals considered to belong to both species as well as the intermediate forms. Our results suggest that in the northeastern Atlantic, Macroramphosus is represented by a single species, M. scolopax, with diVerent morphotypes interbreeding in the sampling areas.
- Phylogenetic relationships of the North-eastern Atlantic and Mediterranean forms of Atherina (Pisces, Atherinidae)Publication . Francisco, S. M.; Congiu, L.; Stefanni, S.; Castilho, Rita; Brito, A. B.; Ivanova, P. P.; Levy, A.; Cabral, H.; Kilias, G.; Doadrio, I.; Almada, V. C.The genus Atherina (Sand-smelts) is distributed in the Eastern Atlantic Ocean and Mediterranean Sea, extending south along the African coast into the Indian Ocean (Quignard and Pras, 1986). It is a genus of small inshore fishes with many populations living in brackish and freshwater. The taxonomy of the genus has been troublesome due to the intraspecific variability of some of its species, the overlap of characters among many of them and because many nominal species were apparently described based on individuals originating from different localities.
- Establishment of a coastal fish in the Azores: recent colonisation or sudden expansion of an ancient relict population?Publication . Stefanni, S.; Castilho, Rita; Sala-Bozano, M.; Robalo, J. I.; Francisco, S. M.; Santos, R. S.; Marques, N.; Brito, A.; Almada, V. C.; Mariani, S.The processes and timescales associated with ocean-wide changes in the distribution of marine species have intrigued biologists since Darwin's earliest insights into biogeography. The Azores, a mid-Atlantic volcanic archipelago located >1000 km off the European continental shelf, offers ideal opportunities to investigate phylogeographic colonisation scenarios. The benthopelagic sparid fish known as the common two-banded seabream (Diplodus vulgaris) is now relatively common along the coastline of the Azores archipelago, but was virtually absent before the 1990s. We employed a multiple genetic marker approach to test whether the successful establishment of the Azorean population derives from a recent colonisation from western continental/island populations or from the demographic explosion of an ancient relict population. Results from nuclear and mtDNA sequences show that all Atlantic and Mediterranean populations belong to the same phylogroup, though microsatellite data indicate significant genetic divergence between the Azorean sample and all other locations, as well as among Macaronesian, western Iberian and Mediterranean regions. The results from Approximate Bayesian Computation indicate that D. vulgaris has likely inhabited the Azores for similar to 40 (95% confidence interval (CI): 5.5-83.6) to 52 (95% CI: 6.32-89.0) generations, corresponding to roughly 80-150 years, suggesting near-contemporary colonisation, followed by a more recent demographic expansion that could have been facilitated by changing climate conditions. Moreover, the lack of previous records of this species over the past century, together with the absence of lineage separation and the presence of relatively few private alleles, do not exclude the possibility of an even more recent colonisation event.
- Unexpected high genetic diversity at the extreme Northern geographic limit of Taurulus bubalis (Euphrasen, 1786)Publication . Almada, V. C.; Almada, Frederico; Francisco, S. M.; Castilho, Rita; Robalo, J. I.The longspined bullhead (Taurulus bubalis, Euphrasen 1786) belongs to the family Cottidae and is a rocky shore species that inhabits the intertidal zones of the Eastern Atlantic since Iceland, southward to Portugal and also the North Sea and Baltic, northward to the Gulf of Finland, with some occurrences in the northern Mediterranean coasts eastward to the Gulf of Genoa. We analysed the phylogeographic patterns of this species using mitochondrial and nuclear markers in populations throughout most of its distributional range in west Europe. We found that T. bubalis has a relatively shallow genealogy with some differentiation between Atlantic and North Sea. Genetic diversity was homogeneous across all populations studied. The possibility of a glacial refugium near the North Sea is discussed. In many, but not all, marine temperate organisms, patterns of diversity are similar across the species range. If this phenomenon proves to be most common in cold adapted species, it may reflect the availability of glacial refugia not far from their present-day northern limits.