Irish Jurassic Brachiopods

Abstract

A survey of brachiopod specimens recovered from the Jurassic of Ireland, and now preserved in the collections of National Museums Northern Ireland (Belfast) and National Museum of Ireland (Dublin), reveals a total of 23 species comprising 12 rhynchonellides, 6 terebratulides, 3 spiriferinides and 2 lingulides. The identity of some taxa remains uncertain, even to generic level, due to difficulties associated with identification from external morphology alone. Most specimens are from the Lower Jurassic, Hettangian to Upper Pliensbachian, of the Lough Neagh-Larne and Foyle-Rathlin basins in Northern Ireland, but the ultimate source of six Upper Pliensbachian species is unclear as they occur only in glacial erratics that may have been transported to north Antrim from the Hebrides Basin of western Scotland. Three species, all rhynchonellides, are recorded from Lower Pliensbachian strata intercepted in a borehole just off the coast of south Dublin. The Irish fauna overall is comparable with that encountered in similar mudstone-dominated facies in Britain, but these records are of interest in providing an extension of their geographic range further west. Small perforations encountered in two examples of Squamirhynchia from the Raricostatum Zone (Upper Sinemurian) may represent the earliest known examples of gastropod predation on Mesozoic brachiopods.