Notes on Carboniferous crinoids from Co. Clare, Western Ireland

Abstract

The disarticulated debris of the Carboniferous crinoids of Ireland is plentiful and varied, but commonly defies description and classification within the Linnaean system. For their craft, crinoid systematists need well-preserved cups and crowns, but the commonest specimens are nondescript columnals and pluricolumnals. In our pursuit of the mid-Carboniferous crinoids of Co. Clare, we have used all available specimens—both complete and disarticulated—collected from three localities and horizons, namely Fisherstreet Bay (Clare Shale Formation), Liscannor (Kilkee Cyclothem) and north of Spanish Point (Doonlicky Cyclothem). We recognise the following taxa classified either in open nomenclature or within morphotaxa, including the morphospecies Heloambocolumnus (col.) harperi Donovan and Doyle, described elsewhere. The vase-shaped cup of Poteriocrinites? sp. is imperfectly preserved, but the column is long and probably homeomorphic throughout; and the arms are uniserial, pinnulate and slender, branching isotomously at least once (IBr1 or 2?). Cladid sp. nov. has a strongly heteromorphic proxistele, N1; a bowl-shaped cup; and robust, uniserial, pinnulate arms, branching isotomously at IBr3. Columnals of Cyclocyclicus (col.) sp. aff. C. triffletonensis Donovan have robust, triangular, unbranched culmina and a column homeomorphic (?) or weakly heteromorphic, N1(?). Circular columnal sp. A is heteromorphic 3231323 distally.