The Lower Cambrian ichnospecies Astropolichnus hispanicus: palaeoenvironmental and palaeogeographic significance

The study of a large number of specimens of the trace fossil Astropolichnus hispanicus (Crimes, Legg, Marcos & Arboleya, 1977) reinforces the opinion that the interaction between the trace maker and the palaeoenvironment; and the preservation of burrows as well, are strongly related to the dynamic conditions in a shallow water subtidal or tidal fiat with alternating shale-silt or sand and occasionally microconglomeratic inputs. The occurrence of A. hispanicus within early Lower Cambrian sequences from Spain, Sardinia (Italy) and Normandy (France) is also discussed with respect to its potential importance as a palaeoenvironmental and biostratigraphical indicator across the Tommotian-Atdabanian boundary and during Atdabanian in the western Gondwana margin. A new palaeogeographical reconstruction for the Northwestern Gondwana during Atdabanian time is given.