Fig. 2: Map and section showing the position of the Onder Karoo locality.

a Geological map showing the Onder Karoo locality (white star) near the foot of Verlatekloof Pass, southwest of Sutherland. The diagonal hatching indicates exposure of probable lower Beaufort Group rocks that appear as Waterford Formation on the geological map of the region⁴⁰. b Map showing the study area in the southwest of the Main Karoo Basin of South Africa. c Representative lithostratigraphic column of the upper Ecca Group and lower Beaufort Group showing the position of the locality and geochronology, after (i)⁴², (ii)⁴³, (iii)¹⁰, and this study. Stratigraphy shows vertebrate assemblage zones within the Beaufort Group. Position of dated beds from different localities reconstructed using the correlations presented in ref. ¹⁰. All ages quoted are U-Pb ages and while the weighted means of U-Pb dates determined through LA-ICP-MS and SHRIMP techniques may appear discordant with CA-ID TIMS U-Pb ages, they are in fact consistent when accounting for their higher error margins.