Two little-known crinoids from the type area of the Devonian, south-west England

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Abstract

There were few publications on the British Devonian Crinoidea between the last parts of the Reverend G.F. Whidborne’s monograph in the 1890s and 1900s and the revival of interest in these faunas in the 21st Century. The paper records two Devonian cladid crinoids collected in the 19th Century; neither was described nor illustrated hitherto. Both are in the collection of the Sedgwick Museum, Cambridge. These specimens are from the Lower Devonian (Emsian) Meadfoot Group (=‘Staddon Grits’) of New Cut, Lincombe Drive (=‘Lincombe Slates’), Torquay, south Devon. Parisocrinus? has been published in name. The cup is deformed and preserved as an internal mould; comparison with the diagnosis of the genus shows that Bather’s determination was questionable. Further, the oldest, confidently determined Parisocrinus is Middle Devonian. However, a second cladid, Vasocrinus sp., not recorded hitherto, is a partial external mould and seems to be correctly determined. A further specimen, on the same specimen board as Vasocrinus, preserves three parallel, pinnulate arms as moulds of the adoral surface; they are unlikely to be conspecific.

Introduction

There were few publications on the British Devonian Crinoidea – that is, the crinoids of the type area of the Devonian and adjacent regions – between the publication of the last part of the Reverend G.F. Whidborne’s monograph (1907) and the revision of the Famennian taxa by Lane et al. (2001). These crinoids received little attention in print during the 20th Century. However, examination of museum collections shows that research went on, albeit at a low key.

The Sedgwick Museum, Cambridge, has a small collection of crinoids preserved as moulds from the Lower Devonian (Emsian) Meadfoot Group of Torquay, south Devon (Fig. 1) and Reed (1920) provided a faunal list for this site. The labels of the crinoids indicate that F.A. Bather (1863–1934) provided the original identifications, but only one of these taxa made Reed’s list (1920, p. 340). It is these few specimens that are considered below.

Terminology of the crinoid endoskeleton follows Ubaghs (1978) and Moore et al. (1978a). Our philosophy of open nomenclature follows Bengtson (1988). The specimens discussed herein are deposited in the Sedgwick Museum, University of Cambridge (SM).

Section snippets

Locality and horizon

Lower Devonian (Emsian) Meadfoot Group undivided (=‘Staddon Grits’) at New Cut, Lincombe Drive (=‘Lincombe Slates’), Torquay, south Devon (Fig. 1). In the Looe Basin, to the west (Scrutton, 1978a, Fig. 2; Leveridge and Shail, 2011, Fig. 3), the Meadfoot Group is divided into the Bovisand Formation (upper Pragian to middle Emsian) overlain by the Staddon Formation (upper Emsian) (Leveridge et al., 2003, Fig. 2). However, in the area of the Torquay High, the Meadfoot Group is undivided and

Systematic palaeontology

Class Crinoidea J.S. Miller, 1821

Subclass Cladida Moore and Laudon, 1943

Family Euspirocrinidae Bather, 1890

Genus Parisocrinus Wachsmuth and Springer, 1880

Type species: Poteriocrinites perplexus Meek and Worthen, 1869, p. 138, by original designation of Wachsmuth and Springer (1880, p. 109) (Moore et al., 1978b, p. T585).

Other nominal species: Webster and Webster (2014, p. 1653) recognised a further seven nominal species of Parisocrinus based on cups and/or crowns.

Diagnosis: See Moore et al.

Acknowledgements

F.E.F. thanks the departments of Earth Sciences and Life Sciences of the Natural History Museum, London, for supporting her attendance at the Ninth European Echinoderm Conference, Sopot, Poland, where this study was first presented as a poster. S.K.D. thanks Naturalis for supporting his research visit to the Sedgwick Museum, Cambridge, in 2012 and Matt Riley for providing enthusiastic access to different parts of the Devonian collections. The constructive comments of two anonymous reviewers are

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