Llanvirn (Middle Ordovician) echinoderms from Llandegley rocks, Central Wales

Abstract

A diverse Llanvirn echinoderm fauna is described from nearshore volcanogenic sandstones of Llandegley Rocks, Builth-Llandrindod Inlier, Powys. The fauna comprises six crinoids (including Cefnocrinus samgilmouri gen. et sp. nov., Iocrinus llandegleyi sp. nov.), three asteroids and one cystoid; at least two indeterminate crinoids and one asteroid represent underscribed taxa, but yielded insufficient material for formal description. Two complex radical root structures are among the oldest recorded examples. Preservation occurs as external moulds, often fully articulated, with fine details preserved through early marginal silicification. The high diversity of this site suggests that the significance of echinoderm palaeocommunities from nearshore areas of low preservation potential is underestimated.