PhD: The Ediacaran biota in miniature: palaeoecological and palaeobiological insights from sub-centimetre fossils

Fossils of the Ediacaran macrobiota are found globally in strata of ~580-541 million years in age, and offer a remarkable record of the early evolution of complex, macroscopic organisms. The precise phylogenetic positions of many Ediacaran taxa remain uncertain, but determination of Ediacaran biological affinities is critical to our understanding of two key evolutionary events, namely the rise of complex multicellularity, and the origin and early diversification of animals. The oldest assemblages of Ediacara-type macrofossils, from Newfoundland (Canada), are particularly problematic, being dominated by frondose forms that share few morphological similarities with modern taxa. Identifying the phylogenetic positions of such taxa will fill a significant gap in knowledge of the patterns and processes underlying early metazoan evolution. Studies into growth and palaeoecology in Ediacaran assemblages have in recent years provided important insights into the biology of Ediacaran taxa, but are often hampered by a paucity of well-preserved juvenile specimens.

This project will investigate growth and palaeoecology in recently discovered assemblages of small (less than 30mm length) specimens of Ediacaran macrofossil taxa from Newfoundland, to more accurately characterize inter- and intra-specific interactions, and to test previous hypotheses relating to reproduction and community succession. A primary focus will be to elucidate the role of filamentous connective structures in Ediacaran ecosystems. Small specimens reflect a significant but previously undocumented component of Ediacaran marine palaeoenvironments, and include both known and undescribed taxa. Additional assessment of ontogeny and development within specific understudied Ediacaran taxa will aim to better constrain their biological affinities.