ENIGMATIC MICROFOSSILS FROM THE MIDDLE DEVONIAN OF THE MADER BASIN IN MOROCCO

Intriguing microfossils have been found on the Middle Devonian brachiopod shell coming from the locality of Madene el Mrakib in the Mader Basin (eastern Anti-Atlas) of Morocco. The microfossils have a flat, frond-like appearance with the central axis and outgrowing thin, lateral, tubular projections. The orientation of particular fronds indicates, that they did not encrust the shell exterior but rather were adhered to the surface and partially covered by a thin sediment layer. The microfossils are preserved in the form of iron oxyhydroxides (likely goethite) which originated following pyrite weathering. The overall appearance of the microfossils indicates that the fronds likely grew vertically. At the moment it is challenging to decipher their biological affinity.

Taking the appearance and size of the fossils into account, they may represent some unknown, Protozoa-grade epibionts. However, it is also tempting to speculate, that the fronds might represent the vertical offshoots of enigmatic ascodictyids. These latter encrusters of still uncertain taxonomic affinity (incertae sedis) are not only abundant on the brachiopods from Morocco but are similarly preserved in the form of goethite and also co-occur with the fronds discussed here. The vertically-growing parts of ascodictyids have never been discovered and thus their appearance is not known. The microfossils have already been subjected to microcomputed tomography (micro-CT) scanning, which may help to identify the organisms.