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

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.

KEYWORDS:

• Upper Triassic – Lower Jurassic
• southern Africa
• Anomoepus
• Eubrontes
• Kayentapus

Article highlights

• Mokhosi preserves three distinct morphotypes that are assigned Anomoepus and Eubrontes, and tentatively to Kayentapus.

• The ichnosite primarily preserves bipedal and quadrupedal trackways.

• More than a third of the tracks preserved at the Early Jurassic ichnosite are attributed to ornithischian trackmakers.

Acknowledgments

We acknowledge Dylan Valley for field assistance. We also thank Jens N. Lallensack, an anonymous reviewer and chief editor Gareth Dyke for meaningfully contributing with their insightful comments to the overall quality of this study. Opinions expressed and conclusions reached are those of the authors and are not necessarily to be attributed to the project funders or anybody else.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/08912963.2023.2221306.

Disclosure statement

The authors received no financial benefit from this research.

Additional information

Funding

The research component of this project was supported from the following research grants obtained by MA as principal investigator: DSI-NRF Centre of Excellence Genus [grant number 86073]; NRF Thuthuka [grant number 138151]; UCT Research Development Grants 2020 – 2021. AR is a recipient of postgraduate funding from the DST-NRF Centre of Excellence in Palaeoscience (Genus). LM is a recipient of postgraduate funding from the DST-NRF Centre of Excellence in Palaeoscience (Genus) and Palaeontological Scientific Trust (PAST), Johannesburg, South Africa; DSI-NRF Centre of Excellence in Palaeoscience.