Tongnanlong zhimingi, a sauropod discovered in Chongqing in 1998, may rank among the largest mamenchisaurs, according to a study in Scientific Reports. The fossils include a scapula over 2 meters long and suggest an overall length of about 25–26 meters (≈82–85 ft). Found in the fossil-rich Sichuan Basin and dated to roughly 147 million years ago, the specimen dwarfs related species such as Astrodon johnstoni. Researchers say the animal’s pneumatic (air-filled) bones helped support its enormous size, but questions about its exact diet and biology remain.
Gigantic 25–26 m Sauropod Unearthed in China — Possibly the Largest Mamenchisaur
Construction workers uncovered a remarkable sauropod skeleton in Chongqing’s Tongnan District in 1998; a recent study in Scientific Reports suggests the specimen, named Tongnanlong zhimingi, may be among the largest mamenchisaur sauropods yet identified.
Where and When
The fossils were recovered from the central Sichuan Basin, a region famed for dinosaur remains. Geological dating places the animal in the Late Jurassic, roughly 147 million years ago.
What Was Found
Excavations revealed parts of the shoulder girdle, hind limbs, tail and multiple vertebrae. The scapula (shoulder blade) alone measures more than 2 meters (about 6.5 ft), a single bone taller than most people. The scapula and associated coracoid are exceptionally large, leading authors to estimate a total body length approaching 25–26 meters.
“The huge-sized scapula and coracoid also indicate that the specimen belongs to an extremely gigantic individual with a body length approaching about 25–26 m,” the study notes.
Size Clarifications
The research authors estimate the animal at roughly 25–26 m (about 82–85 ft) long. Some media reports have rounded the figure to ~92 ft (≈28 m); the study’s anatomical measurements support the 25–26 m range as the primary scientific estimate.
Biology and Comparisons
Tongnanlong zhimingi belongs to the Mamenchisaur lineage of sauropods, known for extremely long necks and bones with internal air cavities (pneumaticity). Those air-filled spaces likely reduced weight and helped support the enormous body. As an herbivore, it would have fed on vegetation reachable with its long neck, though the exact diet and feeding strategy that enabled such large size remain under investigation.
The specimen would far exceed the size of Astrodon johnstoni, a sauropod discovered in Maryland in 1858 and estimated at about 50–60 ft (15–18 m). Astrodon was designated Maryland’s state dinosaur in 1998 — coincidentally the same year the Chongqing specimen was found.
Why It Matters
This discovery adds a significant data point to our understanding of sauropod diversity and gigantism in the Late Jurassic of Asia. Large shoulder elements like the >2 m scapula provide important clues to body proportions and locomotion in the biggest dinosaurs.
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