Australia: The Land Where Time Began

A biography of the Australian continent 

Ediacaran Bilaterian Animals – Trace Fossil Evidence of Complex Behaviours

Chen et al. say it can be a challenge to distinguish trace fossils of Ediacaran age from tubular body fossils and several Ediacaran fossils have previously been interpreted as tubular animal fossils. There are, nonetheless, trace fossils in Ediacaran deposits, though the relatively few that have been found are morphologically simple, being dominated by horizontal trails and shallow burrows. Such simple morphologies have usually been interpreted as evidence for modest behavioural complexity and geobiological impacts of animal bioturbators that are limited prior to the Cambrian explosion. In this paper Chen et al. report trace fossils of 3 types - horizontal tunnels, surface tracks/trails, and vertical traces – from the Dengying Formation, 551-541 Ma, in the area of the Yangtze Gorges, South China, from the latest Ediacaran. The presence of scratch marks and cross-cutting tunnels indicate it is not likely to be tubular body fossils; These 3 types of traces are likely to represent the activities of animals related to feeding under mats, epibenthic locomotion, and temporary dwelling, respectively. Chen et al., show that bilaterian animals constructed these 3 types of traces, which had interactions with microbial mats in order to exploit the nutrients and oxygen resources. Chen et al. say a new age of ecosystem engineering, animal-sediment interactions, and biogeochemical cycling was heralded by animals.

Sources & Further reading

1. Chen, Z., C. Zhou, M. Meyer, K. Xiang, J. D. Schiffbauer, X. Yuan and S. Xiao (2013). "Trace fossil evidence for Ediacaran bilaterian animals with complex behaviors." Precambrian Research 224(0): 690-701.