An exceptional diverse trilobite ichnofauna from the uppermost Devonian of Anti-Atlas, Morocco

We present a highly diverse ichnoassemblage of latest Devonian (Famennian) age from the eastern Anti-Atlas of Morocco, dominated by trilobite and other arthropod trace fossils. It consists of invertebrate and vertebrate ichnotaxa, including Cruziana lobosa, Diplichnites gouldi, Rusophycus antiatlasensis isp. nov., Rusophycus cf. carleyi, associated with Arenicolites isp., Fustiglyphus isp., Lockeia isp., Mammillichnis isp., Planolites isp., Paracanthorhaphe isp., Treptichnus isp., and Undichna isp. These ichnoassemblages are ascribed to the archetypal Cruziana ichnofacies, indicating a shallow-marine environment within low hydrodynamic-energy settings, stable substrate conditions and regular organic matter sources. The results of this ichnological study are remarkable in the following aspects: (i) the report of the youngest occurrence of C. lobosa, (ii) introduction of R. antiatlasensis isp. nov., as a new ichnospecies and (iii) the evidence of collective behaviour and predation as well as protection strategies of trilobites. Judging from the diversity of the invertebrate and vertebrate trace fossils and previously described fish and cephalopod remains, a shallow marine ecosystem was present during the latest Devonian in the eastern Anti-Atlas.