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Rangeomorph classification schemes and intra-specific variation: are all characters created equal?

Published version
Peer-reviewed

Type

Article

Change log

Authors

Kenchington, CG 
Wilby, PR 

Abstract

Rangeomorphs from the Ediacaran of Avalonia are among the oldest known complex macrofossils and our understanding of their ecology, ontogeny and phylogenetic relationships relies on accurate and consistent classification. There are a number of disparate classification schemes for this group, which dominantly rely on a combination of their branching characters and shape metrics. Using multivariate statistical analyses and the diverse stemmed, multifoliate rangeomorphs in Charnwood Forest (UK), we assess the taxonomic usefulness of the suite of characters currently in use. These techniques allow us to successfully discriminate taxonomic groupings without a priori assumptions or weighting of characters and to document a hitherto unrecognized level of variation within single taxonomic groups. Variation within the currently defined genus Primocandelabrum is too great to be realistically assigned to different species and may instead reflect primary character diversity, ontogenetic changes in character state or ecophenotypic variability. Its recognition cautions against generic-level diagnoses based on single differences in character state and will be crucial in understanding the mode of growth of these enigmatic organisms.

Description

Keywords

37 Earth Sciences, 3705 Geology

Journal Title

Geological Society, London, Special Publications

Conference Name

Journal ISSN

0305-8719
2041-4927

Volume Title

448

Publisher

The Geological Society of London
Sponsorship
Natural Environment Research Council (NE/I005951/1)
CGK and PRW were funded by National Environment Research Council grant NE/1005927/1. CGK also acknowledges a Research Studentship funded by the Cambridge Philosophical Society.