Biogeography of the fire salamander (Salamandra salamandra, L.) in Portugal

Dissertação de mest., Biologia Marinha, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2008

Several 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.