Dr. Jennifer Hoyal Cuthill and Dr. Simon Conway Morris's paper was publised in Nature Ecology and Evolution (2017).
The title of paper is "Nutrient-dependent growth underpinned the Ediacaran transition to large body size".
Also, here is a link to a blog Dr. Jennifer Hoyal Cuthill wrote for Nature Ecology and Evolution's Behind the Paper series:
https://natureecoevocommunity.nature.com/channels/521-behind-the-paper/posts/18378-why-did-fossils-of-the-ediacaran-biota-appear-suddenly-at-large-size
Reference
For more details, please see the press release and attached documents (1) (2).
ELSI Researchers | Jennifer Hoyal Cuthill