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A lower Silurian (Llandovery) diplobathrid crinoid (Camerata) from mid-Wales

Published online by Cambridge University Press:  16 March 2020

Fiona E. Fearnhead ,
Stephen K. Donovan Open the ORCID record for Stephen K. Donovan [Opens in a new window] ,
Joseph P. Botting  and
Lucy A. Muir
Fiona E. Fearnhead
Affiliation:
Angela Marmont Centre, Natural History Museum, Cromwell Rd, LondonSW7 5BD, UK Garden Flat, 61a, Highgate West Hill, Highgate Village, London, N6 6BU, UK
Stephen K. Donovan*
Affiliation:
Taxonomy and Systematics Group, Naturalis Biodiversity Center, Postbus 9517, 2300 RALeiden, the Netherlands
Joseph P. Botting
Affiliation:
Department of Natural Sciences, Amgueddfa Cymru – National Museum Wales, Cathays Park, CardiffCF10 3NP, UK Nanjing Institute of Geology and Palaeontology, 39 East Beijing Road, Nanjing, 210008, China
Lucy A. Muir
Affiliation:
Department of Natural Sciences, Amgueddfa Cymru – National Museum Wales, Cathays Park, CardiffCF10 3NP, UK
*
Author for correspondence: Stephen K. Donovan, Emails: [email protected] and [email protected]
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Abstract

Early Palaeozoic crinoids are known only patchily from the British Isles except for accumulations at starfish beds. A single, exquisitely preserved crinoid is reported from the Telychian (Llandovery, Silurian) of the Pysgotwr Grits Formation of the Llangurig area, Powys, mid-Wales. This sedimentary succession is turbiditic in origin and poorly fossiliferous. The crinoid is a diplobathrid camerate, Euptychocrinus longipinnulus sp. nov., preserved as an external mould without counterpart. It has a high, shuttlecock-like crown; a conical, unsculptured cup; low infrabasals; a pair of long, slender, feather-like arms on each ray, each bearing numerous long pinnules; and a heteromorphic column. Most previous reports of this genus have been from the Upper Ordovician – lower Silurian series of Laurentia; uncertainly, it is described from the Upper Ordovician deposits of Morocco (Gondwana). Euptychocrinus longipinnulus is the first Avalonian occurrence. The beautiful preservation of the arms, including cover plates of pinnules, contrasts with the proxistele, which is a series of ‘broken sticks’. This crinoid responded to an adverse environmental fluctuation, probably a turbidity current, by autotomizing the stem, but it was carried downslope and buried alive.

Keywords

systematicsDimerocrinitidaeEuptychocrinuspreservationTelychian
Type
Original Article
Information
Geological Magazine , Volume 157 , Issue 7 , July 2020 , pp. 1176 - 1180
Copyright
© Cambridge University Press 2020

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