STRATIGRAPHICAL AND GEOGRAPHICAL DISTRIBUTION OF MISSISSIPPIAN CRINOIDEA FROM IRELAND

Irish crinoids were first mentioned in the scientific literature more than 200 years ago, and they are amongst the most abundant fossil remains in Mississippian strata of Ireland. The stratigraphic and geographic occurrences and nomenclatural status of 82 named species assigned to 48 genera of Mississippian crinoids from Ireland are evaluated (two species are designated as nomena dubia). Irish crinoids are reported from 52 known localities plus 11 additional localities that cannot be localised. This compilation is garnered from the literature and from museum collections at Trinity College Dublin and Geological Survey Ireland. Crinoids occur in Hastarian to Brigantian strata. The most abundant and diverse crinoid faunas occur in the mixed carbonate-siliciclastic ramp habitat preserved at Hook Head, County Wexford (Ivorian), with 48 crinoid species assigned to 26 genera recorded. Following this, numerous late Tournaisian localities across Ireland associated with Waulsortian carbonate mudbanks include 16 genera. All major clades were represented but camerate crinoids dominated faunas, which could in part be a taphonomic artefact because of their tightly sutured calyx plates. The cover beds at Feltrim Hill Quarry, north County Dublin, provide the most representative upper Chadian (early Viséan) view of crinoid populations. This post-Waulsortian facies includes a mixture of taxa, including a few genera that were important in the underlying carbonate mudbanks but also several new and rare genera. Subsequently, during the Viséan (Arundian to Brigantian regional substages) faunas are represented by all major crinoid clades with a total generic richness of 21, with camerates and advanced eucladids co-dominant.