Exceptionally preserved conulariids and an edrioasteroid from the Hunsrück Slate (Lower Devonian, SW Germany)

Abstract

Nineteen partial specimens of Conularia sp., together with an articulated agelacrinitid edrioasteroid and several discinid brachiopods, occur in close association with a probable biological substrate on a small slab of silty Hunsrück Slate (Lower Devonian, Emsian) from Bundenbach, Germany. Most of the conulariids occur in V-like pairs or in a single cluster of 12 specimens arranged in a fan-like radial pattern. Together with the edrioasteroid and (possibly) brachiopods, the conulariids probably were attached to the substrate in life and then were buried and possibly killed by a single influx of silty mud. The apertural end of many of the conulariids is partially covered by inwardly folded short lappets, which may have closed in response to rapid (but gentle) burial. Rock matrix in the apertural region of the peridermal cavity of nearly all of the conulariids exhibits irregular, variably dense concentrations of pyrite. The concentrations occur almost exclusively within the conulariids, where they probably formed as a result of the decay of retracted conulariid soft parts. Although the concentrations lack clearly defined anatomical features that can be unambiguously homologized with particular anatomical structures of any extant taxon, their form and distribution within the conulariids are consistent with the hypothesis that conulariids were polypoid scyphozoans. © The Palaeontological Association.