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Article: A novel respiratory architecture in the Silurian mollusc Acaenoplax

Palaeontology - Vol. 58 Part 5 - Cover Image
Publication: Palaeontology
Volume: 58
Part: 5
Publication Date: September 2015
Page(s): 839 847
Author(s): Christopher D. Dean, Mark D. Sutton, Derek J. Siveter, and David J. Siveter
Addition Information

How to Cite

DEAN, C.D., SUTTON, M.D., SIVETER, D.J., SIVETER, D.J. 2015. A novel respiratory architecture in the Silurian mollusc Acaenoplax. Palaeontology, 58, 5, 839-847. DOI: 10.1111/pala.12181

Author Information

  • Christopher D. Dean - Imperial College London Department of Earth Sciences and Engineering London UK (Email:
  • Mark D. Sutton - Imperial College London Department of Earth Sciences and Engineering London UK (Email:
  • Derek J. Siveter - University Museum of Natural History Earth Collections Oxford UK (Email:;
  • Derek J. Siveter - University of Oxford Department of Earth Sciences Oxford UK
  • David J. Siveter - University of Leicester Department of Geology Leicester UK (Email:

Publication History

  • Issue published online: 28 August 2015
  • Article first published online: 01 January 1970
  • Manuscript Accepted: 29 May 2015
  • Manuscript Received: 19 January 2015

Funded By

NERC. Grant Number: NE/F018037
Leverhulme Emeritus Fellowship. Grant Number: EM‐2014‐068
Imperial College and Royal School of Mines Association UROP

Online Version Hosted By

Wiley Online Library
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Extant aplacophorans, a group of shell‐less vermiform molluscs, respire through appendages within or projecting from a posterior cavity. Respiratory structures differ between the subclasses Caudofoveata (ctenidia within the cavity) and Solenogastres (folds of the mantle itself). Acaenoplax hayae, a Silurian vermiform mollusc from the Herefordshire Lagerstätte, England, exhibits characteristics of both these groups. While recent work places it within the crown group Aplacophora, near the caudofoveates, initial observations suggested that its respiratory structures were closer to those of the solenogastres. Here, we present new reconstructions of the posterior of Acaenoplax prepared with the aim of resolving features obscured when prior studies were undertaken. These reconstructions detail a novel posterior architecture, not closely comparable to that of either extant aplacophoran group, in which respiratory projections arise from a membrane that partly encloses a central posterior cavity. The posterior membrane is flanked by small spherical projections; both membrane and spherical projections are apparently unique within the Aplacophora. The existence of this previously undocumented respiratory system underlines the diversity of the aplacophoran clade during the Palaeozoic.

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