EVOLUTIONARY DIVERSITY OF NEGLECTED TERRESTRIAL ANIMALS: A MULTI-APPROACH ANALYSIS ON SELECTED ARTHROPOD LINEAGES

Most of animal species currently inhabiting the world are still undescribed, according to multiple independent estimates. However, the degree of underestimated knowledge in species diversity varies markedly even among invertebrate taxa, implying different resolution of investigation is required depending on the extent of the taxonomic (and even geographic) gap of information. As a matter of fact, in some comparatively well-known taxa (e.g., Lepidoptera: Papilionoidea), unresolved diversity is mainly concentrated at the level of relatively small groups of strictly related species and requires geographic fine-scale investigation to assess additional diversity. In contrast, in more poorly investigated taxa (e.g., Chilopoda: Geophilomorpha), the validity and delimitation of major and broadly diversified evolutionary lineages encompassing many species (such as subfamilies and families) remain uncertain even across broad geographical regions, such as the Western Palearctic. In my PhD project, I addressed two case studies in collaboration with other researchers at two different evolutional scale with an integrated approach that combine molecular and morphological data. In the first case study, we compared the fine-scale patterns of differentiation between two divergent butterfly species inhabiting mountain regions, Erebia euryale (Esper, 1805) and Erebia ligea (Linnaeus, 1758), in a small area in the Alps. We tested the phylogeographic pattern of E. euryale and E. ligea at fine geographic scale, sampling specimens across South-eastern Alps and more densely in a narrow region including Dolomiti Bellunesi, for a total of several tens of butterfly sampled. We used analyses based on genome-wide SNP data (obtained through ddRAD sequencing) to delineate the lineages inhabiting the region and we assessed the phenotypic differentiation between the lineages through phenotypic clustering based on morphological data obtained from wings and male copulatory structures). The comparison of differentiation patterns of E. euryale and E. ligea in the Dolomiti Bellunesi revealed that the two species were structured in two population groups, which substituted each other in the same zone for both species, but with a dissimilar level of differentiation between the two species. thus, the differentiation patterns of E. euryale and E. ligea may be considered “pseudo-concordant”. An article reporting this study has been submitted and is now under revision for the journal Ecology & Evolution. In the second case study, we provided a revision of a group of soil centipedes present in the Western Palearctic, the Dignathodontinae, with regards to their taxonomic diversity, morphological diversification, geographic distribution, and evolutionary history. We tested and revised the species-level taxonomy, evaluating all published morphological information and also complementing it with original data obtained thorough the examination of many representative specimens. Also, we updated the known geographical range of the species by evaluating all published and many new records using a set of explicit criteria of validation. Furthermore, we investigated the phylogeny of Dignathodontinae generating whole-genome resequencing data, producing a high-quality genome, using it as a reference for extracting the BUSCO genes from the other genomes, and employing them to infer a phylogeny through different approaches. As a result, we provided an updated diagnosis of the entire Dignathodontinae and the included genera and subgenera. In addition, for each recognized species, including three newly recognized species, we provided a standardized diagnosis, a summary of its taxonomic and nomenclatural history, and a critical account on its known geographic distribution. Finally, we estimated the phylogeny of Dignathodontinae, including 14 of the 23 candidate species recognized by us in the revision. This second study is included in this thesis as a manuscript draft.