Big oyster, robust echinoid: an unusual association from the Maastrichtian type area (province of Limburg, southern Netherlands)

Large, denuded tests of holasteroid echinoids were robust benthic islands in the Late Cretaceous seas of northwest Europe. A test of Hemipneustes striatoradiatus (Leske) from the Nekum Member (Maastricht Formation; upper Maastrichtian) of southern Limburg, the Netherlands, is encrusted by a large oyster, Pycnodonte (Phygraea) vesiculare (Lamarck). This specimen is a palaeoecological conundrum, at least in part. No other members of the same...