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.