Open Paleo

Chungkingosaurus

Dong et al., 1983 CHUNG-CHING-o-SAWR-us

Named after Chongqing (formerly romanized as Chungking), the city in Sichuan Province, China where fossils were found, + Greek sauros ('lizard'), meaning 'Chongqing lizard'.

170.9–154.8 million years ago Bajocian–Oxfordian, Middle Jurassic–Late Jurassic
Middle Jurassic and Late Jurassic stages

Chungkingosaurus is a genus of stegosaurian dinosaur from the Late Jurassic Upper Shaximiao Formation in what is now China. The type species is Chungkingosaurus jiangbeiensis.

Under dispute

Chungkingosaurus has been recovered as the sister taxon of Huayangosaurus in Huayangosauridae (Maidment and colleagues, 2008), in a basal clade with Huayangosaurus (Raven and Maidment, 2017), and as the earliest-diverging stegosaurid (Sánchez-Fenollosa and Cobos, 2025). With its family placement unresolved and Huayangosauridae not retained, it is placed at Stegosauria incertae sedis.

Diagnosis

  1. Dorsal and caudal vertebrae amphiplatyan; four sacral plus one robust dorsosacral vertebrae completely fused with fenestrated dorsal surface
  2. Armor thick and large, consisting of both spinous plates and pear-shaped dorsal plates with constricted acute apex and expanded transverse base
  3. Femoral shaft tubular, straight, and lacks a fourth trochanter; femur-tibia ratio approximately 1.26 (proportionally long tibia)
  4. Astragalus and calcaneum completely fused to distal tibia and fibula
  5. Dentition small and slender in tight alignment but not superimposed; crowns asymmetrical and crescentic with weak enamel and inconspicuous denticles

Species

Chungkingosaurus jiangbeiensis Dong et al., 1983

Type species

Named for the district of Jiangbei in Chongqing, China, where the fossils were found.

Holotype
CV00206 , Chongqing Museum of Natural History
Material
Incomplete skeleton: rostral skull region, 10 dorsal vertebrae, complete pelvic girdle and sacral region, 23 articulated caudal vertebrae, pair of femora and tibia, distal humerus, three metacarpals, five armor plates
Horizon
upper Shaximiao Formation, Bajocian–Oxfordian, Middle Jurassic–Late Jurassic , 170.9–154.8 million years ago
Locality
Maoershi, Chongqing, China

Notable specimens

  • CV 00208

    Chongqing Museum of Natural History complementary

    Only specimen preserving the articulated thagomizer: two pairs of stout obliquely vertical tail spikes plus a unique additional pair of long thin nearly horizontal spikes at the tail end, a pin-cushion array. The holotype lacks articulated thagomizer remains.

    Dong et al. (1983)

References

  1. Dong, Z.; Zhou, S.; Zhang, H. (1983). [Dinosaurs from the Jurassic of Sichuan]. Palaeontologica Sinica, New Series C, Whole Number 162(23): 1-136. dong1983a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the mass and hip height estimates, and the appearance features.

    jones2026a
  3. Maidment, S. C. R.; Norman, D. B.; Barrett, P. M.; Upchurch, P. (2008). Systematics and phylogeny of Stegosauria (Dinosauria: Ornithischia). Journal of Systematic Palaeontology 6(4): 367-407. Informa UK Limited. doi:10.1017/S1477201908002459

    Recovered Chungkingosaurus as the sister taxon of Huayangosaurus in Huayangosauridae in its Stegosauria phylogeny.

    maidment2008a
  4. Sánchez-Fenollosa, S.; Cobos, A. (2025). New insights into the phylogeny and skull evolution of stegosaurian dinosaurs: an extraordinary cranium from the European Late Jurassic (Dinosauria: Stegosauria). Vertebrate Zoology 75: 165-189. doi:10.3897/vz.75.e146618

    Recovered Chungkingosaurus as the earliest-diverging stegosaurid in its stegosaurian phylogeny.

    sánchez-fenollosa2025a
  5. Raven, T. J.; Maidment, S. C. R. (2017). A new phylogeny of Stegosauria (Dinosauria, Ornithischia). Palaeontology 60(3): 401-408. doi:10.1111/pala.12291

    Recovered Chungkingosaurus in a basal clade with Huayangosaurus in their stegosaur phylogeny.

    raven2017a