Best Master Prize

Best master’s thesis award 2022

This year's best master’s thesis award was given to Serafin Streiff for his work entitled "Herbarium phylogenomics, taxonomy and floral evolution in Connaraceae ", conducted at the University of Basel.

Connaraceae is a poorly studied, pantropical angiosperm family that is particularly diverse in complex reproductive systems, such as di- and tristyly. However, a lack of molecular phylogenetic framework and stable taxonomy, especially in the tribe Cnestideae, precludes further research on this family. We leverage recent advances in sequencing herbarium specimens to greatly expand the molecular sampling of Cnestideae using the Angiosperms353 target enrichment approach. Based on our well-supported phylogeny, we find Cnestidae is monophyletic, but the largest genus, Rourea is polyphyletic. In a formal taxonomic revision of the tribe, we propose a new circumscription of Rourea, accepting the genera Byrsocarpus, Roureopsis, Santaloides and Santaloidella, and an amended Rourea s.str. Together with previously recognised Agelaea, Cnestis and Pseudoconnarus, all phylogenetically strongly supported and morphologically characterised, these genera now form the tribe Cnestidae. Moreover, we document that reproductive system evolution is rather labile, but we cannot statistically differentiate between a scenario where tristyly or distyly is ancestral. Based on morphological evidence, we consider ancestral tristyly with multiple transitions to distyly more plausible. Finally, in congruence with previous theories, we infer Connarceae to have dispersed out of Africa to other tropical regions both by geodispersal and long-distance dispersal, resulting in its present pantropical, disjunct distribution. Overall, our updated taxonomy increases ease of identification, and in combination with the phylogeny it also enables future research into evolutionary aspects of this family.