Possibly the Oldest Stegosaur With Tiny Head, Long Tail Spikes Discovered in China

A new stegosaur with overly-large backplates was discovered recently. The dinosaur, which had long tail spikes and a slim head, might have been among the oldest dinosaurs of its genealogy, a new research suggests.

Bashanosaurus primitivus in China

The armored giant, called Bashanosaurus primitivus, is considered a new species from the stegosaur group. The creature lived during the Middle Jurassic period, which occurred about 174 million to 164 million years ago.

The new stegosaur species was theorized to dominate the landmass of modern-day China. Experts are convinced that the Bashanosaurus primitivus is one of the first stegosaurs of the time. In addition, corresponding clues point out that the plant-eating dinosaur originated from the vast continent of Asia before spreading around many parts of the globe.

Chongqing Laboratory of Geoheritage Protection and Research expert Ning Li, who was also the co-lead of the study, said in a Live Science report that the evidence highly suggests that the Bashanosaurus primitivus belongs to the oldest records of Stegosauria in the prehistory of Earth.

Bashanosaurus primitivus was first discovered back in 2015. The first piece of the dinosaur's remains was recovered by Chongqing's shepherd Zheng Zhou. The bone-like stone was then relayed to Li's laboratory, and upon analysis, was confirmed that the material is indeed a dinosaur fossil.

Oldest Stegosaur Species?

Laojun Village served as a paleontological site for about two years. Throughout their research, Li's team uncovered a number of assorted dinosaur bones that total 5,000 pieces. Among the collection, the experts were able to assemble the new stegosaur species.

Bashanosaurus primitivus was the selected name for the latest armored dinosaur as it was derived from Chongqing's ancient name "Bashan," and the Latin's translation of "first." The 168-million-year herbivore measured about 2.8 meters in length from snout to tail. The physiology of this new dinosaur from China is much smaller compared to its predecessor.

Sediments along the site where the Bashanosaurus primitivus was unearthed showed that the particular stegosaur roamed in a delta nearby lake when the region was under a hot drought.

The prehistoric creature's discovery contributes to the limited list of known stegosaurs. Up until today, there are only 14 species of stegosaurs confirmed. Most of the known species were recovered in every continent of the planet, excluding Australia and Antarctica.

Bashanosaurus primitivus is quite unique from the previous findings. The base of the dinosaur's armor plate is positioned upwards and is much thicker compared to the stegosaurs of the Middle Jurassic period, Li explained.

The authors speculate that stegosaurs may have originated from Asia, as the oldest known species prior to Bashanosaurus primitivus, which are the Chungkingosaurus (Chongqing lizard) and the Huayangosaurus (Huayang lizard), were discovered in China's Shaximiao Formation.

Further studies are needed to confirm the possibility of stegosaur's Asian origins, as well as the comparison between the Bashanosaurus primitivus to other fossils of the same period.

The study was published in the journal Vertebrate Paleontology, titled "New Stegosaurs from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China."

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