Preliminary report on new echinoderm Lagerstätten from the Upper Ordovician of the eastern Anti-Atlas, Morocco

Four distinct echinoderm Lagerstätten have recently been discovered in the Upper Ordovician of the eastern Anti-Atlas, Morocco. They have yielded hundreds of exquisitely preserved specimens. Their taphonomy and associated lithology both suggest rapid, in situ burial. Here we discuss the diverse range of assemblages represented and their significance to the diversity of echinoderms in the Lower Palaeozoic. The oldest assemblage (Izegguirene Formation, lowermost Caradoc) is dominated by eocrinoids, large ophiuroids, and mitrate stylophorans associated with rare crinoids. It shows strong similarities with slightly older faunas described from the underlying Ouine-Inirne Formation (Llandeilian) in the Central Anti-Atlas. The second assemblage (lower part of the Lower Ktaoua Formation, lower-middle Caradoc) is composed of eocrinoids (Cardiocystites) and small ophiuroids (encrinasterid indet.). The third assemblage was collected in the upper part of the Lower Ktaoua Formation (lowermost Ashgill). This ’starfish’ bed is dominated by ophiuroids and large solutes, associated with common diploporites and rhombiferans, and rare crinoids and mitrates. Finally, the youngest assemblage (lower part of Upper Tiouririne Formation, lower Ashgill) has yielded abundant remains of edrioasteroids and rhombiferans. © 2010 Taylor & Francis Group

Comments on the ophiuroid family Protasteridae and description of a new genus from the Lower Devonian of the Fox Bay Formation, Falkland Islands

© 2016 Australasian Palaeontologists.Asterozoan fossils are comparatively rare in Gondwana compared with Laurentia, especially in the Devonian. We examined the only fossil ophiuroid yet known from the Falkland Islands and assess its significance for the evolution of the clade. This ophiuroid, herein distinguished as a new genus and species, Darwinaster coleenbiggsae, belongs to the same suprageneric group as Protaster, which was established on a series of Middle–Upper Ordovician taxa and persisted into the late Palaeozoic remarkably little changed in morphology. This single example is part of a much wider fauna that includes fossils from the Bokkeveld Group, South Africa and the Precordillera of Argentina. Existing palaeobiogeographic reconstructions confirm that these faunas once existed on contiguous terranes and characterized a distinct suite of similar palaeoenvironments within the Malvinokaffric Realm. This study reviews the existing record of Devonian asterozoans and revises Protasteridae