Petalocrinus (Echinodermata, Crinoidea) from the Llandovery (Lower Silurian; Rhudannian) of the Girvan district, SW Scotland

Abstract

Synopsis The discovery of distinctive arms of the cladid crinoid Petalocrinus sp. cf. P. visbycensis Bather at Rough Neuk Quarry, near Girvan, Ayrshire, extends the geographical range of this genus and also represents the earliest Petalocrinus in the British Isles; indeed, they are among the earliest specimens of this genus known. The only previous record of this genus from the British Isles was from the Woolhope Inlier, of Herefordshire, in the Petalocrinus Limestone (Telychian). The oldest articulated crinoids from the Silurian of Scotland are from the Mulloch Hill Sandstone Formation (upper Rhuddanian) of Rough Neuk Quarry. New Petalocrinus and other discoveries from this formation provide fresh insight into the Scottish Llandovery crinoids. Poor preservation affects the fossil record of Llandovery crinoids, influencing our views of fauna distribution and diversity.

New taxa and phyletic evolution of the Aeronian (Llandovery, Silurian) Petalocrinidae (Echinodermata, Crinoidea) in Guizhou, South China Block

“…This was accompanied by a rise in sea level with the waning of the Late Ordovician-early Silurian glaciations. As suggested by Fearnhead and Harper (2007), this rise in sea level reestablished epicontinental seas and promoted faunal migrations. A global distribution of Petalocrinus occurred earlier than the typical cosmopolitan Wenlockian faunas (Witzke et al, 1979).…”

“…A global distribution of Petalocrinus occurred earlier than the typical cosmopolitan Wenlockian faunas (Witzke et al, 1979). During the Llandovery, Petalocrinus first occurred on the Laurentia paleocontinent (Mulloch Hill Formation, Scotland, Rhuddanian; Fearnhead and Harper, 2007). By the Wenlock, Petalocirnus was present on the South China Block, Laurentia, Baltica, and Avalonia paleocontinents (Mao et al, 2015).…”

“…This family flourished during the Llandovery and Wenlock. Systematic study of early Silurian crinoids advanced considerably beginning in the 1980s with faunas reported from Iowa (Witzke and Strimple, 1981), Ohio (Ausich, 1984a, b, 1985, 1986a, b, c, d, 1987a, b; Ausich and Dravage, 1988; Boyarko and Ausich, 2009), Kentucky (Ausich et al, 2015), New York and Canada (e.g., Eckert, 1984, 1990; Eckert and Brett, 2001; Ausich and Copper, 2010), and Britain and Ireland (e.g., Donovan and Sevastopulo, 1989; Donovan, 1993; Donovan and Harper, 2003; Donovan and Lewis, 2005; Fearnhead and Donovan, 2007a, b; Fearnhead and Harper, 2007; Donovan et al, 2008, 2009, 2010, 2012). All Silurian Petalocrinidae in China are from the Upper Yangtze Epicontinental Sea, South China Block.…”

Chinese origin and radiation of the Palaeozoic crinoid family Petalocrinidae

“…Hopkinton Dolomite, Iowa), and Petalocrinus must have migrated globally during a Llandovery interglacial. As suggested by Fearnhead and Harper (2007), the geographic distribution of Petalocrinus may be indicative of geographic proximity of tectonic blocks within a sub-equatorial distribution.…”

“…cf. P. visbyensis from the Mulloch Hill Formation (Rhuddianian; Llandovery; Fearnhead and Harper, 2007) of Scotland (Laurentia) (Fig. 2).…”