Julian Bibermair

13.12.2022

Evolution and significance of morphological characters in phylactolaemate bryozoans

PhD Student
Advisor: Thomas Schwaha

Unit for Integrative Zoology, Department of Evolutionary Biology
University of Vienna

Abstract

Phylactolaemates constitute a small, exclusively fresh water inhabiting clade of bryozoans. Within bryozoans, their phylogenetic position is considered early branching as sister group to the vast majority of predominantly marine, calcified myolaemates. Hence investigations on their morphology and neuro-/myoanatomy are crucial for ground pattern reconstruction of the entire phylum, but also for in-group implications on character evolution. Accordingly, this project aims to investigate certain aspects of phylactolaemate morphology to obtain a ground pattern for the clade and assess the evolution of those characters. The morphological analyses are complemented by a new, transcriptome-based phylogeny, that confirms the 6 phylactolaemate families. Modern morphological analyses were already conducted for some of those families. For the early branching Lophopodidae comparable results were still missing. Thus, confocal microscopy experiments and section-based 3D-reconstruction were used to assess the morphology of lophopodids. Ultimately, the resulting data were published in peer reviewed journals and could establish new characters for lophopodids. Further, the phylogenetic position of the ambiguously discussed species of Plumatella fruticosa needs to be investigated. Although currently assigned to Plumatellidae, the species shows a mosaic of plumatellid and fredericellid characters. Our most recent phylogeny showed that it is most closely related to a Cristatellidae and Pectinatellidae. In order to find more resemblances to the latter two families, modern methods were used to investigate the morphology of P. fruticosa to assess morphological characters supporting such a placement.