Filling the gap: Sponge morphology in the phylogenomic era

• Applicant: Professor Dr. Gert Wörheide
• Subject Area: Palaeontology ; Evolution, Anthropology
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 417752052

The simple anatomy and early nature of sponges makes them pivotal for our understanding of early animal evolution. However, in the last twenty years they have been at the core of two major controversies. Both their monophyly and position in the animal tree of life have been questioned by molecular phylogenetics, but the traditional morphological evidence was largely ignored. We consider that may have been caused by the lack of a solid understanding of sponge morphology from an evolutionary perspective. Sponge morphology is complicated because their anatomy is simple and prone to homoplasy. Previous studies have been plagued with methodological issues: sub-optimal coding practices and insufficient character counts being the most pervasive. The aim of this project is to construct a solid morphological framework for sponges to compare it to the current phylogenomic hypotheses in order to create a consensus phylogeny for the phylum. Here, we propose a strategy to counter previous methodological problems, aiming to effectively fill the gap in our knowledge about the morphological evolution of sponges. By sampling characters from all aspects of sponge biology we plan to not only comply with the fundamental principle of total evidence, but also to better represent the real breadth of morphological characters of sponges. Coding-related issues will be addressed by using a criterium of maximum reductio to create simpler and more manageable characters, and by posing explicit hypotheses of homology to exploit previously untapped information-rich features. Succesful results would have major ramifications for both the study of early animal evolution, sponge systematics, and for the future of morphological studies in the current phylogenomic era.

• DFG Programme: Research Grants