Spatial analyses of Ediacaran communities at Mistaken Point

• Main Authors: Mitchell, EG, Butterfield, NJ
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2018
• Subjects: 31 Biological Sciences; 3103 Ecology; 3104 Evolutionary Biology; 37 Earth Sciences; 3705 Geology; Mistaken Point; Newfoundland
• Online Access: https://www.repository.cam.ac.uk/handle/1810/274450; https://doi.org/10.17863/CAM.21576

<jats:title>Abstract</jats:title><jats:p>Bedding-plane assemblages of Ediacaran fossils from Mistaken Point, Newfoundland, are among the oldest known records of complex multicellular life on Earth (dated to ~565 Ma). The in situ preservation of these sessile but otherwise deeply enigmatic organisms means that statistical analyses of specimen positions can be used to illuminate their underlying ecological dynamics, including the interactions between taxa.</jats:p><jats:p>Fossil assemblages on Mistaken Point D and E surfaces were mapped to millimeter accuracy using differentiated GPS. Spatial correlations between 10 well-defined taxa (<jats:italic>Bradgatia</jats:italic>, Charniid,<jats:italic>Charniodiscus</jats:italic>,<jats:italic>Fractofusus</jats:italic>, Ivesheadiomorphs, Lobate Discs,<jats:italic>Pectinifrons</jats:italic>,<jats:italic>Plumeropriscum</jats:italic>,<jats:italic>Hiemalora</jats:italic>, and<jats:italic>Thectardis</jats:italic>) were identified using Bayesian network inference (BNI), and then described and analyzed using spatial point-process analysis. BNI found that the E-surface community had a complex web of interactions and associations between taxa, with all but one taxon (<jats:italic>Thectardis</jats:italic>) interacting with at least one other. The unique spatial distribution of<jats:italic>Thectardis</jats:italic>supports previous, morphology-based arguments for its fundamentally distinct nature. BNI revealed that the D-surface community showed no interspecific interactions or associations, a pattern consistent with a homogeneous environment.</jats:p><jats:p>On the E surface, all six of the abundant taxonomic groups (<jats:italic>Fractofusus</jats:italic>,<jats:italic>Bradgatia</jats:italic>, Charniid,<jats:italic>Charniodiscus</jats:italic>,<jats:italic>Thectardis</jats:italic>, ...