A major dinosaur discovery in China — the "nearly complete and exquisitely preserved" skeleton of what's being described as the "grandmother" of all giant, four-footed sauropods — has been announced by an international team of scientists, including a paleontologist from the Canadian Museum of Nature.

The researchers say the 200-million-year-old specimen is particularly important because of its intact skull and its key position in the evolutionary timeline of a family of dinosaurs that grew larger than any others and came to dominate Jurassic-era Earth.

Yizhousaurus sunae, the fossilized creature unearthed near the southern China city of Lufeng, was the 10-metre-long forerunner of many long-necked, sauropod dinosaurs, such the 40-metre, 120-tonne Amphicoelias.

The research team describes it as "the first complete skeleton of a pivotal ancestor of Earth's largest land animals."

Led by paleontologist Sankar Chatterjee, of Texas Tech University, the team is scheduled to describe the discovery in detail on Sunday at a Geological Society of America conference in Denver.

Xiao-chun Wu, chief of earth-science research at the Ottawa-based Museum of Nature, was involved in identifying the layer of rock from which the specimen was excavated and contributed to the photographic analysis of the bones, he told Postmedia News on Thursday.

The fragile skulls of early sauropods are almost always found in a fragmented state, the researchers said, making the discovery of Yizhousaurus a "very rare and crucial" contribution to understanding the rise of a key group of dinosaurs.

"Sauropods have these big bones but their skulls are very lightly constructed and also very small," Chatterjee said in a summary of the team's findings.

He also noted that scientists have long sought to trace physiological connections between older dinosaurs found in the same part of China and fossils of younger ones that came long after.

"This new one may bridge this gap," Chatterjee said.

The animal's skull is described as having "numerous serrated and spoon-shaped teeth" that would "shear and slide past each other for cutting plant material during feeding."

Like modern-day giraffes, the early sauropod — a plant-eating dinosaur — would stretch its long neck up to tear the leafy branches of trees, its prime food source.

"Once the plant food was ingested, a gastric mill in the stomach probably provided further mechanical breakdown of the plant," Chatterjee stated.

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