Tsikoane suppl. material

The upper Stormberg Group of Lesotho has an
abundant and diverse ichnological record that dates to the Early Jurassic.
Herein, we re-evaluate a known ichnosite in the lowermost Clarens Formation
(Karoo Supergroup) at Tsikoane in northern Lesotho. The site was reported to
preserve tridactyl tracks as natural casts in the ceiling of overhangs and true
track impressions on a fallen sandstone block. At least three track-bearing
palaeosurfaces, associated with horizontally laminated sandstones and desiccated
green mudstones, can be traced over a distance of 250 m. Associated with one of
the track-bearing palaeosurfaces, discrete, U-shaped, cross-sectional structures
are interpreted as a series of natural casts, surface tracks, true tracks and
undertracks. Although the Tsikoane tracks were historically assigned to a
single ichnogenus, later synonymized with Grallator, our findings show a
higher diversity of tridactyl ichnites, with tracks that have Kayentapus-like
and Eubrontes-like features in addition to previously recognized Grallator-like
features. These new findings, within their high-resolution sedimentological
context, improve the understanding of theropod palaeodiversity and
palaeoecology in southern Africa during a crucial period in dinosaur history
marked by increases in both abundance and diversity.