The
Archaeocursor holotype specimen, L01-HY999, was discovered in 2022 in outcrops of the
Ziliujing Formation (Dongyuemiao Member) near
Chongqing Central Park in
Yubei District of
Chongqing Municipality, China. The collection of this bone was part of an operation by the Southeast Sichuan Geological Team to salvage paleontological materials during construction in a residential area, and it is now accessioned in the Chongqing Municipal Bureau of Planning and Natural Resources. The specimen consists of an isolated nearly complete left femur. The specimen was first mentioned in a paper describing the fossil assemblage of the
type locality (named the Yuzhou Biota), which represents a
lacustrine ecosystem. Well-preserved specimens of diverse plants, invertebrates, fish, and pliosaurids are also represented in the outcrops. This assemblage represents a faunal turnover shortly following the
end-Triassic extinction. The discovery of an ornithischian dinosaur in this context is notable; it likely happened to be washed into the lake after its death. After being announced in December 2024 as a non-finalized
preprint, Yao et al. (2025)
described Archaeocursor asiaticus as a new genus and species of early ornithischians based on this fossil specimen. The
generic name,
Archaeocursor, combines the
Latin words
archaeo, meaning "archaic" or "old" and
cursor, meaning "runner". The
specific name,
asiaticus, is a Latin word meaning "from Asia".
Archaeocursor is one of the only ornithischians known from the Early Jurassic of Asia, with the armored
thyreophoran Yuxisaurus being one of the few others. It is the oldest and earliest-diverging named ornithischian from Asia. == Description ==