Fossil evidence unveils an early Cambrian origin for Bryozoa

A team of researchers from universities in China, the UK, the US, Australia and Sweden have published new evidence of the earliest fossilized occurrence of bryozoans in the geological record. In this study published in Nature, fossils of Protomelission gatehousei obtained from Cambrian-age deposits of Australia and South China were evaluated by X-ray microtomography and scanning electron microscopy. Dragonfly was used for 3D segmentation and visualization of different morphological features within the fossil in order to evaluate the exoskeleton structure. The results indicate a Cambrian origin for phylum Bryozoa, pushing back this origin by ca. 35 million years compared to previous estimates.

According to lead author Dr Zhiliang Zhang, “Applying x-ray microtomography to the study of these fossils presented a unique opportunity to observe the morphology and structure of overall exoskeleton in exceptional detail”. Dr Sarah Jacquet, a co-author on the paper, was involved in the 3D segmentation process and says “Dragonfly is ideal for morphological descriptions and 3D rendering of micro-CT scans.” She added “I have trialed my fair share of 3D image processing software and find that the workflow in Dragonfly is straightforward and offers a spectacular range of visualization options. The program has it all when it comes to segmentation and producing publication grade visuals. I have also been very impressed by the analytical applications and prospect of training a segmentation algorithm using deep learning.” For the purpose of this paper Dr Zhiliang Zhang says “The 3D renders of the separate components of the exoskeleton were central in supporting our conclusion that these early Cambrian fossils were indeed bryozoans.”


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Zhiliang Zhang, Zhifei Zhang, Junye Ma, Paul D. Taylor, Luke C. Strotz, Sarah M. Jacquet, Christian B. Skovsted, Feiyang Chen, Jian Han, Glenn A. Brock. Fossil evidence unveils an early Cambrian origin for Bryozoa. Nature 599, 251-255 (2021).

State Key Laboratory of Continental Dynamics

Data Availability

CT scans and parameters used for scanning of specimens in this publication can be accessed in the MorphoSource Repository ( and and the affiliated project (

Keywords: Bryozoa, Fossil, Nature, Segmentation, Imaging, Versa, Cambrian Origin


Image of modular P. gatehousei from µCT data, showing the frontal walls (blue), basal walls (red) and median mesotheca (green) with secondary phosphatic cement (yellow) of the colony.

The early Cambrian bryozoan Protomelission gatehousei. a, scanning Electron microscope image showing colony with individual capsules called zooids that held separate individuals of the colony; b, and c internal structures from different orientations revealed by µCT segmentation. Colours are added to show different structures.

3D rendering of Bryozoa specimen in Dragonfly showing features of the exoskeleton.