Riches of the Roma valley: theropod and ornithischian tracks from the Early Jurassic southern Africa

Abstract

ABSTRACT The Upper Triassic – Lower Jurassic Stormberg Group, main Karoo Basin, is notably rich in diverse dinosaur trace fossils, particularly in the Roma Valley of western Lesotho. Here, we document in detail, for the first time, the Mokhosi ichnosite (Roma Valley), initially reported simply as preserving tridactyl tracks. Thirty-five pes tracks were identified, predominantly preserved as bipedal and quadrupedal trackways attributable to theropod and ornithischian trackmakers. Three distinct morphotypes consisting of pes or manus-pes pairs were assigned to Anomoepus, Eubrontes and tentatively to Kayentapus. Our Morphotype III, although comparable to Kayentapus, preserves quantitative and qualitative features distinct from other large southern African Kayentapus-like tracks, and possesses some characteristics that lean to an ornithischian affinity rather than theropod. Ultimately, the Mokhosi ichnosite contributes to the diverse ichnological record of the Roma Valley, which now includes 15 ichnosites that preserve Anomoepus, Eubrontes, Grallator, Kayentapus and Trisauropodiscus. Furthermore, this site provides essential data for refining our understanding of Early Jurassic ornithischians in Gondwana, which are minor components of the trace- and body-fossil records.