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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: Steve.Donovan@naturalis.nl and SKennethDono@gmail.com
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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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References

Aldridge, RJ, Siveter, DJ, Siveter, DJ, Lane, PD, Palmer, D and Woodcock, NH (2000) British Silurian Stratigraphy. Geological Conservation Review Series. Peterborough: Joint Nature Conservation Committee, xviii+542 p.Google Scholar
Ausich, WI and Copper, P (2010) The Crinoidea of Anticosti Island, Québec (Late Ordovician to early Silurian). Palaeontographica Canadiana 29, 1–157.Google Scholar
Baumiller, TK and Ausich, WI (1992) The broken-stick model as a null hypothesis for crinoid stalk taphonomy and as a guide to the distribution of connective tissue in fossils. Paleobiology 18, 288–98.CrossRefGoogle Scholar
Blyth Cain, JB (1968) Aspects of the depositional environment and palaeoecology of crinoidal limestones. Scottish Journal of Geology 4, 191–208.CrossRefGoogle Scholar
Botting, JP (2018) Late Ordovician crinoids from the Anti-Atlas region of Morocco. In The Great Ordovician Biodiversification Event: Insights from the Tafilalt Biota, Morocco (eds Hunter, AW, Álvaro, JJ, Lefebvre, B, van Roy, P and Zamora, S). Geological Society of London, Special Publication no. 485, https://doi.org/10.1144/SP485.4.Google Scholar
Brower, JC (1973) Crinoids from the Girardeau Limestone (Ordovician). Palaeontographica Americana 7, 263–499.Google Scholar
Brower, JC (1975) Silurian crinoids from the Pentland Hills, Scotland. Palaeontology 18, 631–56.Google Scholar
Brower, JC (1994) Camerate crinoids from the Middle Ordovician (Galena Group, Dunleith Formation) of northern Iowa and southern Minnesota. Journal of Paleontology 68, 570–99.CrossRefGoogle Scholar
Davies, JR, Fletcher, CJN, Waters, RA and Wilson, D (1997) Geology of the country around Llanilar and Rhayader. Memoir of the British Geological Survey, sheets 178 and 179, 267 pp.Google Scholar
Davies, KA (1933) The geology of the area between Abergwesyn (Breconshire) and Pompsaint (Carmarthenshire). Quarterly Journal of the Geological Society, London 89, 172–200.CrossRefGoogle Scholar
Donovan, SK (1989) The significance of the British Ordovician crinoid fauna. Modern Geology 13, 243–55.Google Scholar
Donovan, SK (1993) A Rhuddanian (Silurian, Lower Llandovery) pelmatozoan fauna from south–west Wales. Geological Journal 28, 1–19.CrossRefGoogle Scholar
Donovan, SK (1994) The late Ordovician extinction of the crinoids in Britain. National Geographic Research and Exploration 10, 72–9.Google Scholar
Donovan, SK (2012) Was autotomy a pervasive adaptation of the crinoid stalk during the Palaeozoic? Geology 40, 867–70.CrossRefGoogle Scholar
Donovan, SK, Lewis, DN and Fearnhead, FE (2012a) Classic localities explained 10: crinoid localities of the Silurian of the British Isles. Geology Today 28, 230–7.CrossRefGoogle Scholar
Donovan, SK, Widdison, RE, Lewis, DN and Fearnhead, FE (2012b) The British Silurian Crinoidea. London: Monograph of the Palaeontographical Society.Google Scholar
Fearnhead, FE (2008) Towards a systematic standard approach to describing fossil crinoids, illustrated by the redescription of a Scottish Silurian Pisocrinus de Koninck. Scripta Geologica 136, 39–61.Google Scholar
Fearnhead, FE and Donovan, SK (2007) New crinoids (Echinodermata) from the Llandovery (Lower Silurian) of the British Isles. Palaeontology 50, 905–15.CrossRefGoogle Scholar
Feldmann, RM, Chapman, RE and Hannibal, JT (eds) (1989) Paleotechniques. Knoxville: Paleontological Society, Special Publication no. 4, 358 p.Google Scholar
Fortey, RA and Edgecombe, GD (2017) An Upper Ordovician (Katian) trilobite fauna from the Lower Ktaoua Formation, Morocco. Bulletin of Geosciences 92, 311–22.CrossRefGoogle Scholar
Miller, JS (1821) A Natural History of the Crinoidea or lily-shaped Animals, with Observations on the Genera Asteria, Eurayle, Comatula and Marsupites. Bristol: C. Frost, 150 p.Google Scholar
Moore, RC and Laudon, LR (1943) Evolution and classification of Paleozoic crinoids. Geological Society of America Special Paper 46, 153.Google Scholar
Moore, RC, Ubaghs, G, Rasmussen, HW, Breimer, A and Lane, NG (1978). Glossary of crinoid morphological terms. In Treatise on Invertebrate Paleontology, Part T, Echinodermata 2, volume 2 (eds Moore, RC and Teichert, C), pp. T229, T231, T233–T242. Boulder and Lawrence: Geological Society of America and University of Kansas.Google Scholar
Shumard, BF (1855) Dr. Shumard’s report. Missouri Geological Survey, Annual Report 2, 137–208 [Not seen].Google Scholar
Ubaghs, G (1978) Skeletal morphology of fossil crinoids. In Treatise on Invertebrate Paleontology, Part T, Echinodermata 2, volume 1 (eds Moore, RC and Teichert, C), pp. T58–T216. Boulder and Lawrence: Geological Society of America and University of Kansas.Google Scholar
von Zittel, KA (1876–1880) Handbuch der Palaeontologie, Band 1, Palaeozoologie. Abt. 1. München & Leipzig: R. Oldenbourg, vii+765 p.Google Scholar
Wachsmuth, C and Springer, F (1885) Revision of the Palaeocrinoidea, part III, section 1. Discussion of the classification and relations of the brachiate crinoids, and conclusion of the generic descriptions. Proceedings of the Academy of Natural Sciences of Philadelphia for 1885, 223-364, 1–162.Google Scholar
Webster, GD (1974) Crinoid pluricolumnal noditaxis patterns. Journal of Paleontology 48, 1283–8.Google Scholar
Webster, GD and Webster, DW (2014) Bibliography and Index of Palaeozoic Crinoids: Paleozoic Crinoids, Coronates, and Hemistreptocrinoids, 1758–2012. viii+2694 pp. http://crinoids.azurewebsites.net/.Google Scholar