New type of stegosaur with spear-like bones is dug up in China

A new species of stegosaur that roamed the Earth some 168 million years ago is the oldest ever discovered in Asia after being unearthed in China.

Remains of the stegosaur, which included bones from the back, shoulder, thigh, feet, and ribs, as well as several armour plates, were found at a site in Chongqing, south west China.

They date to the Bajocian stage of the Middle Jurassic period — much earlier than most known stegosaurs — and are possibly the oldest stegosaur fossils ever discovered worldwide, according to researchers.

The paleontologists say they hope their discovery will shed light on how stegosaurs evolved. 

The new species has been named Bashanosaurus primitivus — ‘Bashan’ in reference to the ancient name for the area of Chongqing in China where the dinosaur was found, and primitivus because it is the Latin for ‘first’.

The relatively small, but fearsome-looking stegosaur measured about 9 feet (2.8 metres) from nose to tail — but scientists can’t tell whether the remains are those of an adult or juvenile. 

It has a smaller and less developed should blade, narrower and thicker bases to its armour plates and other features that are different from all other Middle Jurassic stegosaurs discovered so far. 

However, it does have similarities with some of the first armoured dinosaurs, which are over 20 million years older. 

‘All these features are clues to the stegosaurs’ place on the dinosaur family tree,’ said lead author Dr Dai Hui, from Chongqing Bureau of Geological and Mineral Resource Exploration and Development. 

‘Bashanosaurus can be distinguished from other Middle Jurassic stegosaurs, and clearly represents a new species.

‘What’s more, our analysis of the family tree indicates that it is one of the earliest-diverging stegosaurs along with the Chongqing Lizard (Chungkingosaurus) and Huayangosaurus. 

‘These were all unearthed from the Middle to Late Jurassic Shaximiao Formation in China, suggesting that stegosaurs might have originated in Asia.’

Dr Hui added: ‘Bashanosaurus is the oldest stegosaur discovered in Asia — and possibly the world.’ 

Instantly recognisable by the huge back plates, long tail spikes and tiny head, stegosaurs were four-legged, plant-eating dinosaurs that lived during the Jurassic and early Cretaceous periods. 

Stegosaur fossils have been found on all continents except for Antarctica and Australia, and 14 species of stegosaur have been identified so far. 

Well-known members of Stegosauria include Huayangosaurus (one of the most primitive stegosaurs), Gigantspinosaurus, notable for its enormous shoulder spines, and Miragaia for its extremely long neck. 

However, the fragmentary fossil material has hindered attempts to understand how the stegosaurs evolved and how they relate to one another. 

Bashanosaurus primitivus has several primitive features that are similar to the earliest stegosaurs — including longer tail vertebrae, a shoulder blade that is narrower and flares out, and features of the back vertebrae that are similar to the early armoured dinosaur Scelidosaurus, which lived during the Early Jurassic.   

The bizarre armour would have been used to fight off meat-eating predators like Allosaurus and Ceratosaurus.

Pictured, a complete stegosaurus fossil on display at the Natural History Museum

Allosaurus fossils have been found with large holes thought to be made by a stegosaur’s tail spike.

The natural weaponry also acted as a thermo-regulatory mechanism to keep the creature cool, and helped to attract mates. 

The fossilised remains of Bashanosaurus also reveal a host of features that make it unique from other known stegosaurs. 

For example, the bony point at the end of the shoulder blade is small and less well developed than in other stegosaurs; a bony projection of the thighbone (fourth trochanter) is positioned below the middle of the shaft; and the bases of the armour plates curve outwards and are thicker than the plates on the backs of its later relatives. 

Study co-author Dr Susannah Maidment, of London’s Natural History Museum, said: ‘The discovery of this stegosaur from the Middle Jurassic of China adds to an increasing body of evidence that the group evolved in the early Middle Jurassic, or perhaps even in the Early Jurassic, and as such represent some of the earliest known bird-hipped dinosaurs.

‘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.’

Bashanosaurus is described in the Journal of Vertebrate Paleontology.

KILLING OFF THE DINOSAURS: HOW A CITY-SIZED ASTEROID WIPED OUT 75 PER CENT OF ALL ANIMAL AND PLANT SPECIES

Around 66 million years ago non-avian dinosaurs were wiped out and more than half the world’s species were obliterated.

This mass extinction paved the way for the rise of mammals and the appearance of humans.

The Chicxulub asteroid is often cited as a potential cause of the Cretaceous-Paleogene extinction event.

The asteroid slammed into a shallow sea in what is now the Gulf of Mexico.

The collision released a huge dust and soot cloud that triggered global climate change, wiping out 75 per cent of all animal and plant species.

Researchers claim that the soot necessary for such a global catastrophe could only have come from a direct impact on rocks in shallow water around Mexico, which are especially rich in hydrocarbons.

Within 10 hours of the impact, a massive tsunami waved ripped through the Gulf coast, experts believe.

Around 66 million years ago non-avian dinosaurs were wiped out and more than half the world’s species were obliterated. The Chicxulub asteroid is often cited as a potential cause of the Cretaceous-Paleogene extinction event (stock image)

This caused earthquakes and landslides in areas as far as Argentina. 

While investigating the event researchers found small particles of rock and other debris that was shot into the air when the asteroid crashed.

Called spherules, these small particles covered the planet with a thick layer of soot.

Experts explain that losing the light from the sun caused a complete collapse in the aquatic system.

This is because the phytoplankton base of almost all aquatic food chains would have been eliminated.

It’s believed that the more than 180 million years of evolution that brought the world to the Cretaceous point was destroyed in less than the lifetime of a Tyrannosaurus rex, which is about 20 to 30 years.