A new species of stegosaur discovered in Asia, albeit a relatively small one, may be the oldest ever found - not only in the region, but possibly in the world, Science Daily has reported.
The new stegosaur, discovered in the village of Laojun in the Chinese municipality of Chongqing, has been measured to be about 2.8 metres from nose to tail. The scientists named it Bashanosaurus primitivus, referencing the ancient name of the Chinese area where it was found and the Latin word for "first" - primitivus.
Among the discovered remains were the bones from the back, shoulder, thigh, feet, and ribs, and even some distinctive armour plates. Yet, this stegosaur is a bit different from all other Middle Jurassic stegosaurs because it has a smaller and less developed shoulder blade, as well as narrower and thicker bases to its armour plates.
"All these features are clues to the stegosaurs' place on the dinosaur family tree", Dr Dai Hui from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development, who led the research, said.
Along with the Chongqing Lizard (Chungkingosaurus) and Huayangosaurus, Bashanosaurus primitivus is one of the earliest-diverging stegosaurs, all of whom were unearthed from the Middle to Late Jurassic Shaximiao Formation in China. This fact led scientists to suggest that all stegosaurs might have originated in Asia.
"China seems to have been a hotspot for stegosaur diversity, with numerous species now known from the Middle Jurassic right the way through until the end of the Early Cretaceous period", said Dr Susannah Maidment, a co-author of the study and a palaeontologist at London's Natural History Museum.
Stegosaurs are among the most recognisable dinosaurs, mainly due to their distinctive huge back plates and tail spikes. Fourteen species of stegosaurs have been identified so far, among them the Huayangosaurus (one of the most primitive stegosaurs), Gigantspinosaurus, who has enormous shoulder spines, and Miragaia, famous for its very long neck. Stegosaur remains have been found on every continent, except for Antarctica and Australia.