PhD: Palaeobiology of the Kuanchuanpu Lagerstätte, the oldest Cambrian exceptional fossil fauna

The fossil record of animals begins in the Cambrian (541 to 485 Ma), evidencing the evolutionary assembly and dramatic radiation of the modern animal phyla. Famously, this episode is particularly well documented by sites of exceptional fossil preservation where fossilization extends beyond routine preservation of bones and shells, to the preservation of soft tissue anatomy that normally rots away. Deposits such as the Burgess Shale, Chengjiang, and Sirius Passet provide fundamental have provided insights into early animal evolution, but these sites are comparatively young (less that 520 Ma) and their exceptional fossils are like roadkill, collapsed to two dimensions. This project focusses on the c. 535 Ma Kuanchuanpu Biota where the fossils retain their original 3D anatomy, preserving everything from embryonic stages of development through to adults, including controversial ancestral deuterostomes, ecdysozoans, cnidarians, as well as a host of undescribed fossil taxa, with the potential to provide fundamental insights into the earliest stages of the Cambrian radiation.

Your aim will be to elucidate the palaeobiology of the Kuanchuanpu Biota, including the developmental biology of taxa represented by different embryonic and post-embryonic stages of development, and phylogenetic analysis to unlock their significance for understanding the evolutionary assembly of animal bodyplans, including the evolution of development.

This research will be aided in particular by Synchrotron Radiation X ray Tomographic Microscopy (SRXTM), which yields sub micron scale characterization of fossil remains, facilitating virtual dissection using computed tomography. This methodology will allow you uncover all aspects of fossil anatomy which is fortunate since fossils in the Kuanchuanpu Biota commonly preserve features of subsurface and internal anatomy. The biological and systematic interpretation of a number of the taxa already described from the Kuanchuanpu Biota, are already the subject of controversy, with debate hinging on whether features of anatomy are biological, taphonomic, or geological. Fortunately, SRXTM also aids discrimination between phases of mineralization related to the replication of biological structure versus later geological mineralization, elucidating the taphonomy of the fossils, as well as helping to arbitrate between competing interpretations of the fossils.

Depending on the interests of the applicant, there is the potential to incorporate combined analysis of morphological and molecular evidence from living, as well as the fossil species, in attempting to constrain the affinity of the fossil species and the timescale of evolutionary history, for example, using molecular clock methodology. Alternatively, there is scope to explore the community structure of the Kuanchuanpu Biota, in comparison to the better-studied Chengjiang and Burgess Shale biotas. Otherwise, you can undertake taphonomy experiments to aid interpretation of the fossils as well as the general process of exceptional fossilization.

Dong, X.-P., Vargas, K., Cunningham, J. A., Zhang, H., Liu, T., Chen, F., Liu, J., Bengtson, S., and Donoghue, P. C. J., 2016, Developmental biology of the early Cambrian cnidarian Olivooides: Palaeontology, v. 59, no. 3, p. 387-407.
Dong, X. P., Cunningham, J. A., Bengtson, S., Thomas, C. W., Liu, J., Stampanoni, M., and Donoghue, P. C. J., 2013, Embryos, polyps and medusae of the Early Cambrian scyphozoan Olivooides: Proc Biol R. Sci, v. 280, no. 1757, p. 20130071.
Donoghue PCJ et al. 2006, Synchrotron X-ray tomographic microscopy of fossil embryos: Nature, v. 442, no. 7103, p. 680-683.
Duan, B., Dong, X. P., Porras, L., Vargas, K., Cunningham, J. A., and Donoghue, P. C. J., 2017, The early Cambrian fossil embryo Pseudooides is a direct-developing cnidarian, not an early ecdysozoan: Proc Biol R. Sci, v. 284, no. 1869.
Han, J., Morris, S. C., Ou, Q., Shu, D., and Huang, H., 2017, Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China): Nature, v. 542, no. 7640, p. 228-231.