Scientists in China have discovered a new dinosaur species in Yunnan Province that lived about 200 million years ago. Wudingloong wui is the oldest-known sauropodomorph, ever found in East Asia. The find advances our knowledge of the early evolution of these dinosaurs in the region.
“Both the phylogenetic analysis and stratigraphic horizon indicate that Wudingloong represents the earliest-diverging and stratigraphically oldest sauropodomorph dinosaur discovered in East Asia so far.”, wrote the authors in their paper, published in Scientific Reports last month. “This new taxon provides further evidence that the southwestern China sauropodomorph assemblage is one of the most taxonomically diverse and morphologically disparate in the pre-Toarcian Early Jurassic worldwide”
A Well-Preserved, Fully Grown Fossil
The fossil includes parts of the skull, neck and back bones, ribs, shoulder bones, and the right forelimb. These remains show the animal was fully grown when it died. The fossil was found in rocks from the Early Jurassic period, a time when dinosaurs were rapidly diversifying.
“The fully co-ossified cranial elements and completely closed neurocentral sutures of the vertebrae demonstrates that the specimen was probably a mature individual.”
Wudingloong’s bones carry unique features. It had a triangular depression above the front jaw (antorbital fossa – a hole that helped lighten the skull) and a ridge along its middle neck bones (ventral keel). It also had a slimmer upper arm bone (humerus), a delicate fifth finger bone whose ends are equal in width, and an oversized claw on its first finger. These traits set it apart from other early sauropodomorphs.
Cranium of Wudingloong wui gen. et sp. nov. (LFGT-YW002). (A) Photograph of the cranium in left lateral view. (B) Interpretative drawing of the cranium in left lateral view. (C) Photograph of the cranium in right lateral view. (D) Interpretative drawing of the cranium in right lateral view. an, angular; aof, antorbital fossa; ar, articular; d, dentary; j, jugal; l, lacrimal; lf, left frontal; lpf, left prefrontal; m, maxilla; p, parietal; pf, prefrontal; pm, premaxilla; po, postorbital; pop, paraoccipital process; q, quadrate; qj, quadratojugal; rf, right frontal; rpf, right prefrontal; sq, squamosal; sa, surangular; stf, supratemporal fenestra; n, nasal. Scale bars equal 5 cm. Image credit: Wang et al., doi: 10.1038/s41598-025-12185-2.
Links Across Continents
Analysis shows Wudingloong wui is closely related to dinosaurs from South Africa and Germany. This suggests that early sauropodomorphs moved across continents when land masses were still connected.
“The close phylogenetic relationship between Wudingloong and Plateosauravus from the Late Triassic Lower Elliot Formation of South Africa and Ruehleia from the Late Triassic of Germany indicates that the dispersal of early sauropodomorphs in East Asia either occurred at least in Rhaetian of the Late Triassic or just happened around the Triassic-Jurassic boundary.”, the scientists said. “Further discoveries of more specimens and other analyses are necessary to test this hypothesis.”
The discovery shows that southwestern China was home to a diverse community of early long-necked dinosaurs, even before the Jurassic.
What are the Sauropodomorphs?
A sauropodomorph is a type of long-necked, plant-eating dinosaur. They’re part of the larger saurischian (“lizard-hipped”) dinosaur group. And are best known for eventually giving rise to the sauropods, the enormous giants like Brachiosaurus and Diplodocus.
Early sauropodomorphs (like Plateosaurus or Wudingloong) were usually smaller, often 2–10 meters long, and had relatively light builds. They walked on two legs or a mix of two and four.
Sauropods emerged from this group and became truly gigantic, some over 30 meters long, walking on all fours with pillar-like legs. Their key features include long necks for reaching high or distant plants, small heads, peg-like teeth for stripping leaves, and long tails for balance or defense.
Sauropodomorphs are the evolutionary line that started as medium-sized, flexible plant-eaters and ended as the largest land animals ever. In this group, Wudingloong wui is now the oldest-known sauropodomorph, ever found in East Asia.