A can of worms-tracing the origins of Ecdysozoa using fossils, molecules and morphology in a Bayesian framework

Project Background

Ecdysozoans comprise some of the most successful invertebrate phyla, such as the arthropods and nematodes. However, other members of the group are less abundant today than they used to be. An amazing fossil record with a focus on newly collected material from the Early Cambrian Sirius Passet may provide means to better understand the nature of the ancestral ecdysozoan and how these many different fossil worms are related to their extant counterparts. It has been debated whether many of these vermiform fossils are subtending various branches of the tree or mainly the group that they resemble the most, the priapulids. This project will seek to integrate fossils, morphology and molecular sequence data to investigate the phylogeny and evolution of the Ecdysozoa.

Project Aims and Methods

Many new fossils have been discovered in the remote Sirius Passet in North Greenland. These new fossils feature unseen characters that may be useful in better understanding the nature of palaeoscolecid worms and their affiliation to living groups. Using these fossils as a template, we will explore the fossil record from different sites and compile their anatomy with modern forms to explore their phylogenetic placement. Furthermore, we will explore the use of combined morphology, molecules and fossils with stratigraphic ages to co-estimate phylogeny and divergence times which may help reveal incidences of convergent evolution that can result in erroneous placements of fossil taxa.

Within the framework of thinking about Ecdysozoan evolution there are several levels of freedom within the student can explore different subject and take the project in new directions. These can range from exploration and description of new taxa, developing methods for visualization and reconstruction of fossils, development of phylogenetic methods or testing methods on other groups of organisms to compare and contrast with. A student with a personal perspective on how the project could evolve and develop is much welcomed.

Project partners

The project features supervisors from Bristol, Bath, The Natural History Museum and KOPRI. All have expertises on the group of animals and the methods used. These supervisors provide for a wealth of intellectual and experiential resource for discussion of findings and mentorship to the candidate. The proximity of Bath and the Natural History museum means that the student will be able to regularly meet these supervisors in person and the British team can easily gather for one day events to discuss the project. The supervisors at KOPRI may visit England for such gatherings, but the student and the lead supervisor will regularly visit South Korea to work on fossil material held in their collections. The Natural History Museum holds collections of extant material along with fossil specimens that may provide for useful comparisons and study when compiling the anatomical matrix for phylogenetic analysis.

Training

The student will be spending time investigating these fossils and learning how to interpret the fossils and reveal as much anatomy as possible using imaging techniques, camera lucida drawings and elemental mapping. Furthermore, the student will become proficient in using R and Linux shell interface for command-prompting.

The student will travel to South Korea for some extended periods to work on material held there. Museum visits to study collections from other localities is also recommended.