Evolutionary morphology of the hyperdiverse Pselaphinae (Coleoptera: Staphylinidae) and possible reasons for their ecomorphological radiation in the context of cave-dwelling, predation and association with ants

• Applicant: Dr. Margarita Yavorskaya
• Subject Area: Systematics and Morphology (Zoology) ; Structural Biology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545056792

In this project, we will investigate the evolutionary morphology of the hyperdiverse Pselaphinae (Coleoptera: Staphylinidae; ca. 10,000 described species). Our aim is to trace the ecomorphological radiation that has produced an enormous variety of lifestyles, such as for instance cave-dwelling, specialized predation, and associations with ants. Despite recent research, the phylogenetic relationships within the group remain mostly unresolved and the latest phylogenetic studies indicate a high degree of paraphyly for the current classification. To achieve our goal, we will therefore first perform a phylogenetic reconstruction with a representative taxon sampling, based on both molecular and morphological data. The few existing studies on the anatomy of pselaphines have shown that many of their external and internal structures have been modified and that the resulting apomorphies can play a key role in resolving the phylogeny of this morphologically extremely diverse group. We will obtain comprehensive morphological data including morphometric measurements using highly efficient anatomical techniques, especially µCT scanning. This and intensive screening of available data will yield a morphological character state matrix, including many features not evaluated in previous phylogenetic studies on Pselaphinae. For most of the extant sampled species, target enrichment methods will be applied to obtain extensive molecular data for phylogenetic reconstruction and dating the ages of subgroups and evolutionary events. The obtained trees (including those from a total evidence approach) will be used as a backbone for further macroevolutionary analyses with the following objectives: (1) to reconstruct major structural transformations that have occurred along the lineages towards extant pselaphine subgroups, and evolutionary links between various feeding types and head morphology; (2) the identification of characters likely associated with increased diversification rates; (3) a comparison of the morphological diversity between various clades and ecological groups and an evaluation of this disparity in a robust phylogenetic context. The last-mentioned subproject will help to reveal and to untangle the expected enormous extent of convergent evolution that has likely occurred in the context of multiple changes of lifestyles, which have in turn very likely played a key role in the ecomorphological diversification of the group. In addition to improving our understanding of the evolutionary history and morphological radiation of Pselaphinae, this project will elucidate the function and biological role of enigmatic characters such as complex cephalic glands and the distinctive and extremely diverse cuticular invaginations (foveae) in various body regions that form key features characterizing the group as a whole and various subunits.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Rolf Georg Beutel; Dr. Bonnie Blaimer