Admissions > PhD by research > Research Projects > Decoding the fossil record of early metazoan development

Decoding the fossil record of early metazoan

development

Supervisors: Professor Philip Donoghue, Professor Stefan Bengtson (NRM Stockholm) and Professor Dong Xiping (Peking University)



From the conception of evolutionary theory, attempts to uncover the large-scale evolutionary relationships among living animals have been dominated by comparative embryology and, despite the rise of molecular phylogenetics, this influence remains pervasive.

Traditionally, the fossil record has been considered devoid of embryological information, and for good reason: early stages embryos and larvae of marine metazoans have the preservation potential of snot. However, new avenues have been opened wide to palaeontological enquiry with recent discoveries of fossilised embryos, at a variety of developmental stages, from rocks of Ediacaran (Xiao et al. 1998. Nature 391:553) and Cambrian age (Bengtson & Yue 1997. Science 277:1645; Dong et al. 2004. Nature 427:237). Integrated with data on extant organisms, these discoveries provide the potential to test and shape hypotheses on the evolutionary and embryological origins of animal phyla. Some of this material also encompasses representatives of the evolutionary grade of organisms in which animal multicellularity was first established.

The project will focus on elucidating the development (embryology and post-embryonic stages) of primitive metazoans and pre-metazoans from the Cambrian Kuanchuanpu Formation and the Ediacaran Doushantuo Formation, both of South China. The successful student will work on existing collections, though there remains the opportunity for them to collect additional material. The material will be studied using conventional light and electron microscopy, as well as synchroton radiation x-ray computed tomography (Donoghue et al. 2006 Nature 442:680), to reconstruct the pattern of development. This information will be used to constrain the evolutionary relations of the fossil organisms among their living relatives. Comparative analyses of development will benefit from culturing living representatives of different animal evolutionary grades and studying their pattern of development. These comparisons will be supplemented with taphonomy experiments to better understand the relationship between structures seen in the development of living animals and in their fossil counterparts (Raff et al. 2008. PNAS 105: 19359). These comparative analyses will reveal evidence of developmental evolution.

Training

The student will be provided with training in advanced light, electron, synchrotron tomographic microscopy and computed tomography. Laboratory techniques for the recovery of fossil embryos will also be explained as will methods of phylogenetic analysis and character evolution. There may be opportunities for field collecting trips to China. The ideal candidate would have a good background in geology and palaeontology, or in biology and evolution.

 

Last updated: 1/11/11