Pleistocene Hamerkop Scopus umbretta (Scopidae) tracks and other new avian ichnosites on South Africa’s Cape south coast

Abstract

Eight Pleistocene avian ichnosites have been identified in aeolianites on South Africa’s Cape south coast, adding to the 41 sites previously identified. All the newly identified sites are thought to fall within the age range of marine isotope stages (MIS) 6 through 4. The Cape south coast sites form the overwhelming majority of known southern African avian fossil ichnosites. The data provided by this profusion of sites may have a role in future ichnofacies assignment. One of the new sites provides the first global record of a Hamerkop Scopus umbretta (family Scopidae) trackway, exhibiting a variation of the typical ‘heron-like track pattern’ as well as lessons in the interpretation of heron-like tracks. The second southern African records of probable stork, heron and crane tracks have also been identified. A site containing large flamingo tracks supports previous inferences of large Pleistocene avian chrono-subspecies. The bias created by larger, heavier birds registering larger, deeper tracks that are easier to recognise probably accounts for the preponderance of large trackmakers identified. The relatively coarse grain size of aeolianite deposits leads to a further bias against the confident identification of small avian tracks. Given the relative paucity of the body fossil record from this time period in southern Africa, the findings provide a necessary perspective on the regional Pleistocene avifauna. The ephemeral nature of these tracksites highlights the need for vigilance and repeated exploration of known high-yield areas.