Browsing by Author "Reis, D. M."
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- Biogeography of the fire salamander (Salamandra salamandra, L.) in PortugalPublication . Reis, D. M.; Castilho, RitaSeveral studies show that the Betic and Messinian crisis may be linked to origin of several Iberian endemic species, while the Pleistocene ice ages cycles are responsible for the fragmentation of species into subspecies and lineages divergence. The present study of the relationships between Salamandra salamandra subspecies (S. s. gallaica and S. s. crespoi) that inhabit the southwestern area of the Iberian Peninsula could contribute to a better understanding of the real impact of these events on the biota. Cytochrome b mitochondrial DNA fragments of 197 individuals from 12 locations were analyzed and a noticeable division was found. Several key nucleotide positions were found as being responsible for this clear division, matching the know distribution of Portuguese salamander subspecies encountered using several analysis (Nested Clade Phylogenetic Analysis, haplotype network and genetic distances), where the center-north populations were grouped into Clade I (S. s. gallaica distribution) and south populations were grouped in Clade II (S. s. crespoi distribution). The calculated neutrality indexes show that every sampled population is relatively stable and that different types of selection appear to be happening in Alcoutim, Serra da Estrela, Sesimbra and Sintra. Monchique in Clade II and Sintra in Clade I both showed high levels of diversity which associated with its geographical characteristics, support the hypotheses of them being past refugia for these subspecies. Douro and Tejo rivers together with the effects of the Pleistocene glaciations played an important role in the highly structured geography differentiation of S. s. gallaica populations, whereas in the case of the S. s. crespoi subspecies they seem to have had no effect, as this one presents a more continuous distribution.
- Genetic structure of Brachidontes puniceus populations in Cape Verde archipelago shows signature of expansion during the last glacial maximumPublication . Cunha, R. L.; Lopes, Evandro P,; Reis, D. M.; Castilho, RitaQuaternary climatic fluctuations had major impacts on species’ distributions over the last 2.5 Myr. Expansions and contractions of the polar ice caps throughout glacial cycles strongly affected terrestrial fauna and flora whereas eustatic sea level variations had major consequences on rocky-shore communities. The effect of these glacial episodes on marine organisms inhabiting oceanic islands is still poorly understood. We analysed the genetic structure of the marine mussel Brachidontes puniceus from the Cape Verde Islands using mitochondrial sequence data. The apparent absence of physical oceanographic barriers or ecological filters in the geographical range of B. puniceus is reflected in the lack of genetic structure found among populations from the entire archipelago. Larval dispersal in B. puniceus likely played a critical role in the demographic connectivity of populations across the Cape Verde archipelago. Results from demographic analysis were consistent with a population expansion promoted by an increase in the habitat available for larval settlement resulting from a low sea-level stand during the last glacial maximum.
- Salamandra salamandra (Amphibia: Caudata: Salamandridae) in Portugal: not all black and yellowPublication . Reis, D. M.; Cunha, R. L.; Patrão, C.; Rebelo, R.; Castilho, RitaThe fire salamander complex is quite diverse in the Iberian Peninsula where nine subspecies of Salamandra salamandra are currently recognized. Here, we analysed the geographical distribution of the subspecies S. s. gallaica and S. s. crespoi using partial sequences of the mitochondrial cytochrome b gene of 168 individuals from 12 locations in Portugal. Our results support the existence of a deep lineage divergence between the two subspecies, with non-overlapping geographical distributions except in two contact zones: one in Sesimbra on the western coast, and another in Alcoutim on the southeastern border with Spain. Moreover, S. s. crespoi displays signs of gene flow among the sampled locations whereas S. s. gallaica shows evidence of some restriction to gene flow. Present-day genetic make-up of S. s. gallaica and S. s. crespoi is a result of past historical events, fine-tuned by contemporary Iberian geoclimate. Humid mountain areas were found to harbour increased genetic diversity possibly acting as past refugia during drier interglacial periods. To analyse wider geographical patterns and lineage splitting events within S. salamandra we performed a Bayesian dating analysis completing our data set with previously published sequences. The observed divergences were associated to successive biogeographic scenarios, and to other Iberian species showing similar trends.