A flexible crinoid from the Llandovery (Silurian) of western Ireland

Abstract

“Complete” crinoids are rare fossils in the lower Paleozoic of Ireland. Cryptanisocrinus kilbridensis n. gen. and sp., from the Upper Llandovery (Telychian) Finny School Beds of the upper Kilbride Formation, County Mayo, is an anisocrinine homalocrinid and the first Irish lower Paleozoic flexible crinoid. The unique holotype is an external mold without counterpart that does not retain the anal series. Cryptanisocrinus kilbridensis has a kylixiform dorsal cup, a low but prominent, infrabasal circlet, low, triangular basals, arms that branch isotomously at least three times, and two interprimibrachial plates in each interray, the lower of which is the larger.