The palaeontology of Ediacaran Avalonia: new insights using morphometrics and multivariate statistical analyses

Hawco, Jessica Bernadette (2020) The palaeontology of Ediacaran Avalonia: new insights using morphometrics and multivariate statistical analyses. Masters thesis, Memorial University of Newfoundland.

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Abstract

The Avalonian Ediacaran fossil assemblage of Newfoundland, Canada contains abundant fossils with a wide range of morphologies and preservational styles. Quantitative morphological and statistical analysis in Ediacaran fossil assemblages has recently been used to recognize natural morphological groupings, providing evidence for variability within and between taxa. This approach is first used herein to test the grouping of the serially arranged, millimeterscale chambered organism known as Palaeopascichnus. The combined morphometric and statistical analytical approach was applied to collected specimens from Ferryland, and demonstrates constrained, discrete growth patterns. The same technique was used to compare fossil palaeopascichnids with extant Protista, which has supported the protistan affinity for the hitherto enigmatic palaeopascichnids. This thesis also statistically investigates an Ediacaran taxonomic dispute known as the Beothukis/Culmofrons problem. The two taxa (Beothukis mistakensis and Culmofrons plumosa) were established separately, but were later synonymized. To determine the validity of this taxonomic reassignment, this thesis investigates the clustering of specimens based on their morphology and morphometrics and assesses the validity of certain taxonomic characters within the specimen dataset. These findings validate the original genus-level differentiation of Beothukis and Culmofrons, while also showing evidence for previously unrecognized variation within the genus Beothukis. Overall, this technique has led to the finding that more morphotypes may exist within the Ediacaran biota than originally thought, and proves the utility of detailed statistical and morphological analysis in determining morphological diversity and disparity.

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