Archaeocursor
From Greek 'archaios' meaning 'ancient' or 'old' and Latin 'cursor' meaning 'runner'; meaning 'old runner'
Archaeocursor is an extinct genus of basal ornithischian dinosaurs from the Early Jurassic Ziliujing Formation of China. The genus contains a single species, A. asiaticus, known from a single femur. Archaeocursor represents the oldest and most basal ornithischian described from Asia.
Under dispute
Archaeocursor is known only from a femur and was recovered as the sister taxon of Eocursor, immediately outside Genasauria, on a single synapomorphy (Yao and colleagues, 2025). The placement is weakly supported and provisional.
Diagnosis
- Femoral proximal surface marked by an anterolateral-posteromedially oriented ridge
- Greater trochanter expands anteroposteriorly to approximately the same width as the femoral head but remains shorter than the anterior trochanter
- Anterior surface of the medial condyle is sculpted, featuring an associated depression on its medial surface
- Lateral condyle occupying roughly 2/3 of the distal transverse width
Species
Archaeocursor asiaticus Yao et al., 2025
Type species
From Latin 'asiaticus' meaning 'from Asia', referring to the Asian provenance of the fossil.
- Holotype
- L01-HY999 , Chongqing Municipal Bureau of Planning and Natural Resources
- Material
- Isolated nearly complete left femur
- Horizon
- Dongyuemiao Member, Ziliujing Formation, Sinemurian–Pliensbachian, Early Jurassic , 199.5–184.2 million years ago
- Locality
- near Congyansi subway station, Chongqing, China
References
- Yao, X.; Zhao, Q.; Ren, T.; Wei, G.; Xu, X. (2025). New evidence for the earliest ornithischian dinosaurs from Asia. iScience 28(1). Elsevier BV. doi:10.1016/j.isci.2024.111641 yao2025a
-
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.
Source of the body length, mass, and hip height estimates.
jones2026a