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Article: New trace fossil evidence for eurypterid swimming behaviour

Palaeontology Cover Image - Volume 61 Part 2
Publication: Palaeontology
Volume: 61
Part: 2
Publication Date: March 2018
Page(s): 235 252
Author(s): Matthew B. Vrazo, and Samuel J. Ciurca
Addition Information

How to Cite

VRAZO, M.B., CIURCA, S.J. 2018. New trace fossil evidence for eurypterid swimming behaviour. Palaeontology, 61, 2, 235-252. DOI: 10.1111/pala.12336

Author Information

  • Matthew B. Vrazo - Department of Paleobiology National Museum of Natural History, Smithsonian Institution Washington DC 20560 USA
  • Samuel J. Ciurca - 2457 Culver Road Rochester NY 14609 USA

Publication History

  • Issue published online: 08 February 2018
  • Manuscript Accepted: 07 October 2017
  • Manuscript Received: 30 April 2017

Funded By

Sigma Xi–University of Cincinnati

Online Version Hosted By

Wiley Online Library
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We describe a recently discovered trace fossil from a eurypterid Konservat‐Lagerstätte in the upper Silurian Tonoloway Formation of Pennsylvania, and formally describe contemporaneous traces from the Williamsville Formation Lagerstätte of Ontario. The traces from both localities are assigned here to Arcuites bertiensis igen. et isp. nov. Based on comparisons with previously described eurypterid trackways, neoichnological experiments, and the co‐occurrence with eurypterid remains, Arcuites is interpreted as having been made by the swimming leg (sixth prosomal appendage) of swimming juvenile to adult eurypteroid eurypterids, and represents the first unambiguous trace fossil evidence for eurypterid swimming behaviour. The morphology of Arcuites indicates that eurypteroid eurypterids swam using drag‐based rowing, whereby the animal propelled itself forward by moving its oar blade‐like swimming paddles in an in‐phase backstroke. Arcuites morphology also indicates that the eurypteroid swimming appendage had a greater degree of movement than was previously suggested, and a revised rowing model is proposed. Differences in the abundance of A. bertiensis in the Tonoloway and Williamsville formations suggest a bathymetric control on eurypterid swimming behaviour and trace production. The association of Arcuites with eurypterid body fossils in both units indicates that these Lagerstätten were autochthonous assemblages and provides additional evidence for eurypterid inhabitation of shallow subtidal marine environments in the late Silurian.

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