A farmer in China stumbled upon some fossils more than a decade ago, which led to an excavation, which led to a realization: It’s time to rethink the evolutionary history of some of the biggest dinosaurs that ever walked the earth.

In a study published this week in the science journal Nature Communications, paleontologists said they had discovered the earliest diplodocoid yet, and the only one to be unearthed in East Asia.

Diplodocoids are part of the sauropod subgroup — the one known for those big plant-eaters with four legs and long necks. The fossils in China belonged to a previously undiscovered species, Lingwulong shenqi, and are about 174 million years old. That’s about 15 million years older than would be expected for a dinosaur of its type.