Browsing by Author "Coelho, Manuela M."
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- Fish diversification at the pace of geomorphological changes: evolutionary history of western Iberian Leuciscinae (Teleostei: Leuciscidae) inferred from multilocus sequence dataPublication . Santos, Carla Sousa; Jesus, T. F.; Fernandes, C; Robalo, Joana Isabel; Coelho, Manuela M.The evolutionary history of western Iberian Leuciscinae, obligatory freshwater fish, is directly linked to the evolution of the hydrographic network of the Iberian Peninsula after its isolation from the rest of Europe, which involved dramatic rearrangements such as the transition from endorheic lakes to open basins draining to the Atlantic. Previous phylogenetic research on western Iberian leuciscines, using mainly mtDNA and more recently one or two nuclear genes, has found contradictory results and there remain many unresolved issues regarding species relationships, taxonomy, and evolutionary history. Moreover, there is a lack of integration between phylogenetic and divergence time estimates and information on the timing of geomorphological changes and paleobasin rearrangements in the Iberian Peninsula. This study presents the first comprehensive fossil-calibrated multilocus coalescent species tree of western Iberian Leuciscinae (including 14 species of Achondrostoma, Iberochondrostoma, Pseudochondrostoma and Squalius endemic to the Iberian Peninsula, six of which endemic to Portugal) based on seven nuclear genes, and from which we infer their biogeographic history by comparing divergence time estimates to known dated geological events. The phylogenetic pattern suggests slow-paced evolution of leuciscines during the Early Miocene endorheic phase of the main Iberian river basins, with the shift to exorheism in the late Neogene-Quaternary allowing westward dispersals that resulted in many cladogenetic events and a high rate of endemism in western Iberia. The results of this study also: i) confirm the paraphyly of S. pyrenaicus with respect to S. carolitertii, and thus the possible presence of a new taxon in the Portuguese Tagus currently assigned to S. pyrenaicus; ii) support the taxonomic separation of the Guadiana and Sado populations of S. pyrenaicus; iii) show the need for further population sampling and taxonomic research to clarify the phylogenetic status of A. arcasii from the Minho basin and of the I. lusitanicum populations in the Sado and Tagus basins; and iv) indicate that A. occidentale, I. olisiponensis and P. duriensis are the most ancient lineages within their respective genera.
- Understanding the mechanisms of antitropical divergencein the seabird White-faced Storm-petrel (Procellariiformes:Pelagodroma marina) using a multilocus approachPublication . Silva, Mónica C.; Matias, Rafael; Wanless, Ross M.; Ryan, Peter G.; Stephenson, Brent M.; Bolton, Mark; Ferrand, Nuno; Coelho, Manuela M.Analytical methods that apply coalescent theory to multilocus data have improved infer-ences of demographic parameters that are critical to understanding population divergenceand speciation. In particular, at the early stages of speciation, it is important to implementmodels that accommodate conflicting gene trees, and benefit from the presence of sharedpolymorphisms. Here, we employ eleven nuclear loci and the mitochondrial control regionto investigate the phylogeography and historical demography of the pelagic seabirdWhite-faced Storm-petrel (Pelagodroma marina)bysamplingsubspeciesacrossitsanti-tropical distribution. Groups are all highly differentiated: global mitochondrial ΦST= 0.89(P < 0.01) and global nuclear ΦSTvaries between 0.22 and 0.83 (all P < 0.01). The completelineage sorting of the mitochondrial locus between hemispheres is corroborated by approx-imately half of the nuclear genealogies, suggesting a long-term antitropical divergence inisolation. Coalescent-based estimates of demographic parameters suggest that hemisphericdivergence of P. marina occurred approximately 840 000 ya (95% HPD 582 000–1 170 000),in the absence of gene flow, and divergence within the Southern Hemisphere occurred190000ya(95%HPD96000–600 000), both probably associated with the profound palaeo-oceanographic changes of the Pleistocene. A fledgling sampled in St Helena (tropicalSouth Atlantic) suggests recent colonization from the Northern Hemisphere. Despite thegreat potential for long-distance dispersal, P. marina antitropical groups have beenevolving as independent, allopatric lineages, and divergence is probably maintained byphilopatry coupled with asynchronous reproductive phenology and local adaptation.