A New Dinosaur Species Discovered in Korea: Doolysaurus huhmini

演化之聲
6 days ago
3 min read

For a long time, dinosaur research in Korea has shown an intriguing pattern: trackways and egg fossils are exceptionally abundant, yet direct skeletal evidence has remained very scarce. This imbalance has left Korean paleontologists with relatively limited anatomical material for studying the morphology, taxonomy, and evolutionary relationships of the region's dinosaurs. Against that background, the discovery of a small dinosaur skeleton represents an important find. This fossil was named Doolysaurus huhmini, with the species name honoring the Korean paleontologist Min Huh. It is a small-bodied, early-diverging neornithischian dinosaur.

Life reconstruction of Doolysaurus huhmini（感謝 Jun Seong Yi 提供） — Life reconstruction of *Doolysaurus huhmini*（感謝 Jun Seong Yi 提供）

The fossil comes from Aphae Island in Shinan County, on the southwestern coast of Korea. It was recovered from the Ilseongsan Formation, a mid-Cretaceous unit dated to roughly the Albian to early Cenomanian, approximately 113 to 97 million years ago. The fossil-bearing strata are mainly composed of homogeneous, fine-grained sandy mudstones associated with calcareous nodules, indicating a relatively stable floodplain environment with steady and fairly rapid sedimentation. Intermittent gravelly sandstone layers and horizons containing bone fragments reflect depositional conditions produced by overflow or crevasse-splay events.

Such an environment is favorable for the preservation of dinosaur remains. Floodplain settings can rapidly bury carcasses, reducing decomposition and disturbance by scavengers, while repeated depositional events allow different types of fossils—including eggs, bones, and trackways—to be preserved within the same broader system. Aphae Island had already yielded a giant theropod egg nest and a variety of dinosaur egg fossils prior to this discovery.

The skeleton of Doolysaurus is preserved in two contiguous rock blocks. Although the cranial and axial elements are partly disarticulated, the hindlimb remains well articulated. Researchers were able to reconstruct its internal and external anatomy using micro-computed tomography (micro-CT), revealing details such as tooth arrangement, cranial structure, and the morphology of the limb bones. This represents the first detailed study of dinosaur cranial material from Korea and greatly improves the taxonomic resolution of the species.

Holotype specimen KDRC-SA-V001（圖片來源：Jung J et al. (2026)，採用 ODbL v1.0 授權）

Correspondence between the preserved skeleton and the reconstructed body; white indicates fossil-supported elements, whereas gray indicates inferred skeletal elements（圖片來源：Jung J et al. (2026)，採用 ODbL v1.0 授權）

Histological analysis indicates that this individual was not fully grown. Examination of the femoral tissue shows that it was still in an active stage of development, and the cranial elements and vertebrae had not yet fully fused. Together, these features suggest that the animal was probably between zero and two years old, indicating that it was a juvenile.

The abdominal region of the specimen also preserves several gastroliths, which were likely involved in food processing. Gastroliths are commonly interpreted as stones used for grinding food and are known in modern birds as well as in some dinosaurs. Based on the morphology and relative characteristics of the gastroliths in this specimen, Doolysaurus may have had a more omnivorous dietary tendency.

Doolysaurus was classified as a member of Thescelosauridae, a widespread group of generally small-bodied, bipedal ornithischian dinosaurs. Most related Asian taxa occupy relatively basal positions within the evolutionary tree of this clade, suggesting that Thescelosauridae may have originated in Asia before dispersing into other regions.

Phylogenetic position of Doolysaurus huhmini（圖片來源：Jung J et al. (2026)，採用 ODbL v1.0 授權） — Phylogenetic position of *Doolysaurus huhmini*（圖片來源：Jung J et al. (2026)，採用 ODbL v1.0 授權）

From an anatomical perspective, Doolysaurus can be distinguished by a combination of features, including a quadrate in which the lateral condyle is larger than the medial condyle, a fibular shaft with a D-shaped cross-section, and an exoccipital in which the exits associated with the hypoglossal nerve are combined into a single opening. This particular suite of features allows it to be differentiated from closely related taxa and also highlights the morphological diversity present within this group during its evolutionary history.

When compared with another known Korean neornithischian, Koreanosaurus boseongensis, clear differences can be seen in femoral morphology. In Koreanosaurus, the anterior margin of the distal femur is relatively flat and meets the medial side at a distinct angle, whereas the corresponding region in Doolysaurus is more rounded and smoothly contoured. This may indicate differences in locomotion or muscle attachment between the two animals.

The discovery of Doolysaurus allows researchers to reassess the diversity and evolutionary relationships of dinosaurs from Aphae Island and Korea more broadly. It also suggests that additional small dinosaur skeletons may still be preserved in similar depositional settings. On this Cretaceous floodplain, there were not only large predators and massive egg nests, but also agile small-bodied animals moving through the same environment, together forming a layered and dynamic ancient ecosystem.