Diversifizierungsmuster und Bauplanevolution der Glasschwämme (Porifera: Hexactinellida) während des Phanerozoikums und eine kritische Evaluation evolutionärer Inferenzmethoden
Bioinformatik und Theoretische Biologie
Evolution, Anthropologie
Systematik und Morphologie der Tiere
Zusammenfassung der Projektergebnisse
Glass sponges (phylum Porifera: class Hexactinellida) are an ecologically important but understudied group of deep-sea animals. They have a long and rich fossil record and were important reef-builders in the Mesozoic, but diversification dynamics of the group throughout the Phanerozoic are still poorly understood. Molecular phylogenies and divergence time estimations of Hexactinellida show a generally good agreement with morphology-based systems and the fossil record. However, they also suggest that the evolution of hexactinellid body plans, i.e. the different construction types of the sponges' supporting skeletons, might have been more complex than originally thought. Unfortunately, some of the phylogenetically most important taxa had not been sampled yet for molecular studies, which made it impossible to disambiguate between possible scenarios of skeletal evolution, and left the higher-level systematics of the group largely unresolved. The project aimed at expanding the existing molecular dataset and produce a wellresolved, time-calibrated phylogeny of glass sponges, which, in combination with data from the fossil record, should then form the basis for a) constructing a revised classification of the group that will facilitate integrating paleo- and neontological research, b) reconstructing the evolution of skeletal features to improve our understanding of the importance of convergence in body plan evolution, and c) reconstructing macroevolutionary diversification dynamics (differential origination and extinction rates of evolutionary lineages, and their causes) of the group throughout the Phanerozoic, which had never been done so far for any poriferan taxon. Furthermore, d) using glass sponges as a case study, a wide range of state-of-the-art methods for phylogeny reconstruction, divergence time estimation, reconstruction of phenotypic character evolution, and reconstruction of diversification-rate patterns were to be explored and critically compared. Increasing the taxon sampling for established molecular phylogenetic markers turned out to be more challenging than anticipated, likely due to poorly preserved DNA in the available specimens, which led to considerable delays of the project. Nevertheless, important progress could be made with respect to aims a) and b), resulting in a revised classification of Hexactinellida and better understanding of body plan and spicule evolution of the group, although some open questions still remain. Some interesting contributions to aim d) were also made regarding molecular clock, phylogenetic inference, and ancestral state reconstruction methods. With respect to aim c), a number of analyses were conducted, which were also relevant to aim d), but these results have to be regarded as preliminary and will be repeated and expanded upon with a new dataset incorporating many more specimens that were only recently acquired and could not be fully processed within the timeframe of the project (work in progress).
Projektbezogene Publikationen (Auswahl)
- 2014. The influence of ignoring secondary structure on divergence time estimates from ribosomal RNA genes. Mol. Phylogenet. Evol. 71:214–223
Dohrmann, M.
(Siehe online unter https://doi.org/10.1016/j.ympev.2013.12.003) - 2014. Three new species of glass sponges (Porifera: Hexactinellida) from the West Indies, and molecular phylogenetics of Euretidae and Auloplacidae (Sceptrulophora). Zool. J. Linn. Soc. 171:233–253
Reiswig, H.M., Dohrmann, M.
(Siehe online unter https://doi.org/10.1111/zoj12138) - 2015. Genomic data do not support comb jellies as the sister group to all other animals. Proc. Natl. Acad. Sci. USA 112:15402–15407
Pisani, D., Pett, W., Dohrmann, M., Feuda, R., Rota-Stabelli, O., Philippe, H., Lartillot, N., Wörheide, G.
(Siehe online unter https://doi.org/10.1073/pnas.1518127112) - 2016. Molecular paleobiology — progress and perspectives. Palaeoworld 25:138–148
Wörheide, G., Dohrmann, M., Yang, Q.
(Siehe online unter https://doi.org/10.1016/j.palwor.2015.01.005) - 2016. Symplectella rowi (Porifera: Hexactinellida: Lyssacinosida) is a rossellid, not a euplectellid. J. Mar. Biol. Ass. U.K. 96:291–295
Dohrmann, M.
(Siehe online unter https://doi.org/10.1017/S0025315414001805) - 2017. An integrative systematic framework helps to reconstruct skeletal evolution of glass sponges (Porifera, Hexactinellida). Frontiers Zool. 14:18
Dohrmann, M., Kelley, C., Kelly, M., Pisera, A., Hooper, J.N.A., Reiswig, H.M.
(Siehe online unter https://doi.org/10.1186/s12983-017-0191-3) - 2017. Dating early animal evolution using phylogenomic data. Sci. Rep. 7:3599
Dohrmann, M., Wörheide, G.
(Siehe online unter https://doi.org/10.1038/s41598-017-03791-w)
