Haootia quadriformis n. gen., n. sp., interpreted as a muscular cnidarian impression from the Late Ediacaran period (approx. 560 Ma).

• Main Authors: Liu, Alexander G, Matthews, Jack J, Menon, Latha R, McIlroy, Duncan, Brasier, Martin D
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2014
• Subjects: Cnidaria; Ediacaran; Newfoundland; metazoan; muscle; Animals; Biological Evolution; Fossils; Geologic Sediments; Newfoundland and Labrador; Phylogeny; Species Specificity; Canada; Moot
• Online Access: https://www.repository.cam.ac.uk/handle/1810/245780

Muscle tissue is a fundamentally eumetazoan attribute. The oldest evidence for fossilized muscular tissue before the Early Cambrian has hitherto remained moot, being reliant upon indirect evidence in the form of Late Ediacaran ichnofossils. We here report a candidate muscle-bearing organism, Haootia quadriformis n. gen., n. sp., from approximately 560 Ma strata in Newfoundland, Canada. This taxon exhibits sediment moulds of twisted, superimposed fibrous bundles arranged quadrilaterally, extending into four prominent bifurcating corner branches. Haootia is distinct from all previously published contemporaneous Ediacaran macrofossils in its symmetrically fibrous, rather than frondose, architecture. Its bundled fibres, morphology, and taphonomy compare well with the muscle fibres of fossil and extant Cnidaria, particularly the benthic Staurozoa. Haootia quadriformis thus potentially provides the earliest body fossil evidence for both metazoan musculature, and for Eumetazoa, in the geological record. We gratefully acknowledge a NERC doctoral studentship to AGL while at the University of Oxford; a Burdett Coutts grant to JJM; and support from the Cambridge Philosophical Society and National Geographic Global Exploration Fund (GEFNE22-11) to AGL. This is the final published version. It was originally published here: http://rspb.royalsocietypublishing.org/content/281/1793/20141202.short?rss=1.