The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very few Konservat-Lagerstätten known so far in the world to have yielded numerous remains of Late Ordovician softbodied fossils associated with... more
The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very few Konservat-Lagerstätten known so far in the world to have yielded numerous remains of Late Ordovician softbodied fossils associated with an abundant and diverse marine benthic fauna. This locality has also yielded several levels (starfish beds) extremely rich in exquisitely preserved echinoderms. Their remarkable preservation possibly results from the rapid, in situ burial of large, particularly dense, living communities (echinoderm meadows) by storm deposits. The Bou Nemrou starfish beds are dominated by eocrinoids and stylophorans, associated with crinoids, cyclocystoids, edrioasteroids, and ophiuroids. This composition is typical of the cool assemblages of the Mediterranean Province. The Bou Nemrou starfish beds may result from the opportunistic colonisation of the sea-floor by dense populations of echinoderms, during short phases of environmental disturbance.
The Lower Devonian Voorstehoek Formation is a lithostratigraphic unit within the Ceres Subgroup of the Bokkeveld Group (Cape Supergroup) in South Africa comprised of essentially mudstones and siltstones. This fossiliferous unit contains... more
The Lower Devonian Voorstehoek Formation is a lithostratigraphic unit within the Ceres Subgroup of the Bokkeveld Group (Cape Supergroup) in South Africa comprised of essentially mudstones and siltstones. This fossiliferous unit contains typical cool to cold water benthic biota (e.g., brachiopods, trilobites, crinoids) from the Malvinokaffric Realm of SW Gondwana, however, to date, not only the taphonomy of Voorstehoek invertebrates is understudied, but in general those of the Early Devonian marine communities of this Realm. The palaeontological and sedimentological features of the Emsian Voorstehoek Formation suggest that deposition took place in a shallow marine environment within the storm-influenced, proximal part of an offshore transition zone. 3D microCT scanning of this obrution bed allows us to report, for the first time from South Africa, on the co-occurrence of fully-articulated remains of both ophiuroids and stylophorans within the same sedimentary layer. Taphonomic analyses of this ophiuroid–stylophoran assemblage suggest a marine obrution deposit, which formed due to the rapid burial of the benthic community during high-energy storms, smothered both autochthonous and allochthonous taxa. This uniquely preserved, mixed ophiuroid–stylophoran assemblage provides a taphonomic window into the marine ecosystems of the Early Devonian, including the structure of a benthic community within the Malvinokaffric Realm of SW Gondwana.
