Demographic interpretation of colossal theropod footprints discoveries from Imilchil (Mid-Jurassic, Central High Atlas, Morocco)

Abstract

Among the footprints found in Imilchil (Central High Atlas, Morocco) are two large ichnites that we characterize as “colossal” to distinguish them from the “giant” theropod footprints in the usage of other authors. These discoveries add to the scarce record of very large footprints, and contribute to the knowledge of the spatial-temporal distribution of such colossal footprints. We classify the sites with dinosaur tracks by their geographic location and age in Temporal Geographical Circumscriptions (TGCs) that lead to the separation of nine TGCs containing colossal theropod tracks. We analyzed the total content of described theropod footprints of the nine TGCs to relate the colossal footprint populations by size. This analysis, which extends from the Middle Jurassic to the Upper Cretaceous, distributes the colossal footprints geographically in a limited (non-random) way. As a consequence of the above, we hypothesze that their distribution may be zonal possibly due to latitude, climate or geographical barriers. localized in different TGCs according to the geological period.