Australia: The Land Where Time Began

A biography of the Australian continent 

Cambrian Explosion - Scyphozoan Olivooides from the Early Cambrian – Embryos, Polyps and Medusae

Embryonic and post-embryonic stages are known of the organism Olivooides from the Early Cambrian, it therefore has the potential to yield vital insights into developmental evolution at the time when establishment was taking place of animal body plans. Only if phylogenetic relationships of Olivooides can be constrained can this potential be realised. Controversy has surrounded the affinities of Olivooides that results from the lack of knowledge of their internal anatomy and the limited range of developmental stages that are known. In this paper the authors² describe rare embryonic specimens in which the internal anatomical features have been preserved, as well as presenting a fuller sequence of fossilised developmental stages of Olivooides which includes associated specimens that have been interpreted by the authors¹ as budding ephyrae (juvenile meducae), with all displaying a clear pentaradial symmetry. The new data, within the framework of cnidarian interpretation, pinpoint the phylogenetic position of Olivooides to the Scyphozoan stem group. The authors² suggest hypotheses of Olivooides affinities with scalidophoran and echinoderms can be rejected.

 Sources & Further reading

1. Dong, Xi-Ping, John A. Cunningham, Stefan Bengtson, Ceri-Wyn Thomas, Jianbo Liu, Marco Stampanoni, and Philip C. J. Donoghue. "Embryos, Polyps and Medusae of the Early Cambrian Scyphozoan Olivooides." Proceedings of the Royal Society B: Biological Sciences 280, no. 1757 (April 22, 2013 2013).