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Fossil insights into the developmental evolution of animal bodyplans during the “Cambrian Explosion”


   School of Earth Sciences

   Applications accepted all year round  Funded PhD Project (Students Worldwide)

About the Project

PROJECT TITLE: Fossil insights into the developmental evolution of animal bodyplans during the “Cambrian Explosion”

Lead Institution: University of Bristol

Lead Supervisor: Prof Philip Donoghue, School of Earth Sciences, University of Bristol

Co-Supervisor: Prof Davide Pisani, School of Earth Sciences, University of Bristol

Co-Supervisors: Prof Zongjun Yin (Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences), Dr Sebastian Willman (Uppsala University), Dr Michael Steiner (Freie Universitat Berlin)

Project Enquiries: Philip Donoghue ()

It is widely appreciated that the origin of animal bodyplans during the Proterozoic-Phanerozoic transition is a consequence of developmental evolution – changes to the patterns and processes of embryological and post-embryonic development that give rise to the evolutionary novelties that distinguish the animal phyla. This is traditionally studied through the comparative embryology of living species, similarities among which can attributed to ancient ancestors. However, it can be difficult to discriminate convergence from ancestry based on such broad scale comparisons – if only we had a fossil record of embryology. Thankfully we do; fossilized embryonic and post-embryonic developmental stages of early animals were first discovered two decades ago and over the intervening years more sites of their exceptional preservation have been revealed (1). By chance, fossilized developmental stages are especially richly preserved within strata representative of the Proterozoic-Phanerozoic transition interval in which animal bodyplans were established. Ediacaran and Cambrian sites in China (2, 3), Mongolia (4, 5) and North Greenland (6) preserve developmental stages attributed to diverse animal phyla, as well as the immediate relatives of animals (7, 8). However, for many, their phylogenetic affinity and evolutionary significance remain poorly constrained, principally due to the challenge of discriminating the biology from geology within the fossil remains, and their assembly into developmental series.

The aim of this project is to decode the fossil record of early animal development through two main objectives (i) comparative study of the fossilization of embryonic remains, including direct analysis of the fossils and experimental taphonomy of living counterparts, and (ii) X-Ray and Computed Tomography of the fossil remains to elucidate their developmental biology and, consequently, their phylogenetic affinity and evolutionary significance. You will use Synchrotron Radiation X-Ray Computed Tomography (srXTM) and computed tomography to non-invasively physically characterise the fossil remains at submicron resolution and, in combination with destructive Electron Probe Micro Analysis (EPMA), you will discriminate the mineral phases that preserve biological structure from later diagenetic mineralization unrelated to the original biology. You will also take an experimental taphonomy approach, characterizing patterns of decay in living animal and animal-relative counterparts, to inform the biological interpretation of the fossils. Finally, you will elucidate the affinity and evolutionary significance of the fossil embryos through comparative embryology and model-based phylogenetic analysis.

You will be provided with training in srXTM, EPMA, SEM, computed tomography, interpretation of the fossil remains and phylogenetic methods. The project involves travel to the Swiss Synchrotron Light Source

(Villigen, Switzerland) and NIGPAS (Nanjing, China), and there are likely to be opportunities for fieldwork in China. More broadly, your intellectual and career development will be fostered through your involvement in our dynamic and diverse lab of international researchers within the broader Palaeobiology Research Group at Bristol.

Funding: This project is fully-funded through a University of Bristol Scholarship, including fees, stipend and research budget funded to UKRI PhD studentship standard.

Start date: September 2022

Further information: please contact Philip Donoghue

To apply: Please follow the instructions found on this webpage How to apply | Study at Bristol | University of Bristol using "Geology PhD" as your programme on this link Start your application | Study at Bristol | University of Bristol and the Sep 2022 start date. The "email now" section below is for enquiries only.


Funding Notes

This project is fully-funded through a University of Bristol Scholarship, including fees, stipend and research budget funded to UKRI PhD studentship standard.

References

1. Donoghue, P. C. J., Cunningham, J. A., Dong, X.-P., and Bengtson, S., 2015, Embryology in deep time. Volume 1: Introduction, Non-Bilateria, Acoelomorpha, Xenoturbellida, Chaetognatha, in Wanninger, A., ed., Evolutionary developmental biology of invertebrates, Volume 1: Introduction, Non-Bilateria, Acoelomorpha, Xenoturbellida, Chaetognatha: Vienna, Springer, p. 45-63.
2. Cunningham, J. A., Vargas, K., Yin, Z., Bengtson, S., and Donoghue, P. C. J., 2017, The Weng'an Biota (Doushantuo Formation): an Ediacaran window on soft-bodied and multicellular microorganisms: Journal of the Geological Society, v. 174, no. 5, p. 793-802.
3. Bengtson, S., and Yue, Z., 1997, Fossilized metazoan embryos from the earliest Cambrian: Science, v. 277, p. 1645-1648.
4. Anderson, R. P., Macdonald, F. A., Jones, D. S., McMahon, S., and Briggs, D. E. G., 2017, Doushantuo-type microfossils from latest Ediacaran phosphorites of northern Mongolia: Geology, v. 45, no. 12, p. 1079-1082.
5. Steiner, M., Yang, B., Hohl, S., Li, D., and Donoghue, P., 2021, Exceptionally preserved early Cambrian bilaterian developmental stages from Mongolia: Nature Communications, v. 12, no. 1, p. 1037.
6. Willman, S., Peel, J. S., Ineson, J. R., Schovsbo, N. H., Rugen, E. J., and Frei, R., 2020, Ediacaran Doushantuo-type biota discovered in Laurentia: Commun Biol, v. 3, no. 1, p. 647.
7. Yin, Z., Sun, W., Liu, P., Zhu, M., and Donoghue, P. C. J., 2020, Developmental biology of Helicoforaminareveals holozoan affinity, cryptic diversity, and adaptation to heterogeneous environments in the early Ediacaran Weng’an biota (Doushantuo Formation, South China): Sciences Advances, v. 6, no. eabb0083, p. 1-10.
8. Yin, Z., Vargas, K., Cunningham, J. A., Bengtson, S., Zhu, M., Marone, F., and Donoghue, P. C. J., 2019, The early Ediacaran Caveasphaera foreshadows the evolutionary origin of animal-like embryology: Current Biology, v. 29, p. 4307-4314.

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