Author(s): Silva, Ana Catarina Afonso, 1988-
Date: 2018
Persistent ID: http://hdl.handle.net/10451/34864
Origin: Repositório da Universidade de Lisboa
Project/scholarship: info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F88740%2F2012/PT;
Subject(s): Teses de doutoramento - 2018; Domínio/Área Científica::Ciências Naturais::Ciências Biológicas
Tese de doutoramento, Biologia (Biologia Evolutiva), Universidade de Lisboa, Faculdade de Ciências, 2018
How speciation, range shifting and reticulation through climatic oscillations combine to shape current patterns of local and regional diversity remains a key question in evolutionary biology. This can be investigated by using multi-scale analyses of closely related species assemblages in diverse communities, such as the lizards of Australia’s tropical savannas. An example of these is the understudied group of rainbow skinks (Carlia) that are broadly co-distributed across the Australian Monsoonal Tropics (AMT) region, and that stands out from most well-studied Carlia species occurring along the Australian east coast. The aims of this thesis were to: i) identify lineage diversity between two sympatric and closely related skinks and to use an integrative taxonomic approach to statistically test major lineages as species; ii) compare past responses of species with different climatic niche breadth that experienced the same climatic fluctuations; iii) infer the phylogenetic relationships of the rainbow skinks in a collaborative study; and iv) explore the occurrence of introgression in a group of six species that broadly cooccur in the AMT, using a dataset by target exon capture (>1000 loci). The investigation of lineage diversity discovered cryptic lineages mostly in the Kimberley region (north west of Australia). In an integrative taxonomic approach, these lineages were then statistically validated as new species using multispecies coalescent methods and morphological analyses, and subsequently described as C. insularis sp. nov and C. isostriacantha sp. nov. with genetic and morphological characters. The exploration of how concordant were the species responses with late Pleistocene climatic changes, identified contrasting responses by species with different climatic niches, suggesting that the narrow climatic specialist species was more sensitive to these changes. In addition, using multiple phylogenomic approaches, it contributed to a much improved and well-supported phylogeny for the rainbow skinks in comparison with a previous, poorly resolved tree. The new tree showed that the six Carlia species that co-occur in the AMT are actually closely related. Lastly, the analysis for the presence of introgression between the AMT sympatric species did not detect evidence of recent admixture, but identified patterns of ancestral introgression before the divergence of sister species, and some instances of introgression in the more climatic unstable Kimberley region. It also showed that by accounting for reticulated evolution with phylogenetic networks methods, a distinct topology from the overall well supported species tree can be observed, in this case with the clade inferred as introgressed appearing as more ancestral in the phylogeny. The results of this thesis have implications for the understanding of the processes driving cryptic species diversity and responses to past climatic change across this richm and understudied Australian Monsoonal Tropics biome.
