Rare taxa in the early animals of the Ediacaran

Supervisor: Dr Emily Mitchell

Co-Supervisors: Professor Jason Head & Dr Frances Dunn

This project will focus on the rare and unusual specimens preserved from Newfoundland, Canada (575-560Ma), to resolve the affinities and abundance of rare taxa. Rare taxa constitute the majority of species within modern communities but identifying rare taxa in the fossil record is hampered by the difficulty in distinguishing between species, taphomorphs, eroded specimens and different morphs of the same species. However, where they have been identified in Ediacaran assemblages, rare taxa can include some of the most significant specimens in an assemblage, extending the evolutionary history of particular animal groups by tens of millions of years (Auroralumina attenboroughii) or have been singled out as exciting targets for future study (Parviscopa bonavistensis). This project will focus on unresolved and rare specimens, understanding how and if they relate to described species, and realise the evolutionary significance of these rare species. 

Type of work 

The student will have access to an extensive photographic and laser-scan data dataset of Ediacaran specimens and use this data alongside existing analyses to document the different reproductive modes within these communities. This project will use a combination of different ecological metrics to estimate how many rare taxa we may expect within the Ediacaran Newfoundland communities. They will use the available specimen information to explore how many unresolved specimens maybe new species, and investigate how different types of taxonomic definitions may relate to our understanding of Ediacaran and how it may change with the inclusion of rare taxa. 

Importance of the area of research concerned 

Life has existed on Earth for more than 3.5 billion years, but it is only around 600 million years ago, during the Ediacaran period (635 – 541 Ma), that animals appear and diversify in the rock record. The radiation of animals across the Ediacaran and subsequent Cambrian period is one of the most transformational events in Earth history, representing a step change in the evolution of the biosphere. While fossils from the Cambrian are readily recognised as belonging to extant groups, those from the late Ediacaran document animals which built their bodies in fundamentally different ways and are ancestors to major animal groups (including Eumetazoa). Key to understanding early animal evolution is understanding how biodiversity changes through these first 15 million years of animal life (575-560Ma) and which animal lineages are present which necessitates understanding exactly how many taxa are present at which time points.

 References 

1. Dunn, F.S., Kenchington, C.G., Parry, L.A., Clark, J.W., Kendall, R.S. and Wilby, P.R., 2022.

2. A crown-group cnidarian from the Ediacaran of Charnwood Forest, UK. Nature Ecology & Evolution, 6(8), pp.1095-1104.

3. Stephenson, N.P., Delahooke, K.M., Barnes, N., Rideout, B.W., Kenchington, C.G., Manica, A. and Mitchell, E.G., 2024.

4. Morphology shapes community dynamics in early animal ecosystems. Nature Ecology & Evolution, 8(7), pp.1238-1247.