Earliest Armoured Dinosaur Discovered

We uncover the latest archaeological ancestor of some of the toughest dinosaurs that used plates like armour.
05 May 2022

Interview with 

Shundong Bi, Indiana University of Pennsylvania

Yuxisaurus kopchicki

Yuxisaurus kopchicki dinosaur


As a child, we remember standing transfixed in the London Natural History Museum in front a the remains of a massive armoured dinosaur; this was one of the group of animals that were covered in thick defensive plates, turning them into living tanks. Now a discovery in China brings us a bit closer to the root of how those animals originated and disseminated worldwide. Shundong Bi set out originally to look for ancient mammal remains but a chance meeting in a village sent him off in a very different direction, and led to the recovery of the new species Yuxisaurus kopchicki, as he explains to Chris Smith...

Shundong - You can imagine this is like an armadillo, but it's much, much bigger in size; about 3 metres long. It's a cover with the thermal plate over the body.

Chris - Basically it's a small car. Is that a reasonable comparison? That sounds long.

Shundong - It's like I say; a truck.

Chris - And when would this have been around?

Shundong - This group included stegosaurus and angolasaurus. It's a runner, from early Jurassic to late Cretaceous. It's roughly 100 million years to 70 million years ago.

Chris - Would it have weighed as much as a truck? If you'd put one of these things on the scales, what would its weight have been?

Shundong - Probably one tonne!

Chris - So it is sort of "car mass" as well. What did they eat? Do we know much about their diet?

Shundong - Based on the teeth, it probably is a herbivore. Leaves or plants, and some juicy fruit.

Chris - It's basically an elephant in terms of size for comparison. It's gonna eat like an elephant as well, and weigh as much as a car. I mean, it's a pretty big thing. How did you find this?

Shundong - I'm a mammal specialist. I was looking for the first mammal, because we believe the first mammal was found in Southwestern China, in the Yunnan province. I led the team to a site 100 kilometres west to the capital city of Yunnan Province. I went to the site and the local people showed me the dinosaur plate and I was impressed. We went out to the field, from site we would take out more than 100 bones, including skull, lower jaw, and the vertebrae.

Chris - Are you saying that the locals had already found this, or at least they'd found some specimens that were one of these, and so that gave you the clue that there were these specimens in the area?

Shundong - Yes. The area also is very rich in fossils. Before they also found a lot of species - sauropods, dinosaurs and also some theropods.

Chris - And did you get the dating from the stratigraphy, in other words, the rocks in which it's found? Or did you date it by finding out what you had got and then comparing it to other things to work out where it must sit in the timeline?

Shundong - The datings are mainly based on the rock sequence. We make a lateral comparison with the nearby locality. At that locality, they already did dating using geochemicals and also based on stratigraphy. We can say with confidence, say this early Jurassic.

Chris - Just so we can appreciate where does that sit then in the timeline of these sorts of dinosaurs, is that really early then in their evolution?

Shundong - I would say it's really early, like the beginning of the Jurassic; really early.

Chris - And so this is the sort of ancestor that would've become the big beasts, like stegosaurs and so on, that we are very familiar with playing with toys of them when we are little. Is that what you're saying? That this is probably the ancestor of some of those very big herbivorous dinosaurs that were plated and well defended.

Shundong - Yes. The other dinosaurs included most famous groups of stegosaurus, ankylosaurus. As you're familiar, stegosaurus have plates along their back. Ankylosaurus has plates all over the body. For this new species, it's a primitive member before the stegosaurus and the ankylosaurus split. It's an ancestor of stegosaurus and ankylosaurus.

Chris - Obviously, if they've got that level of defence, they must have it for a reason. There must have been, around at the same time, things capable of penetrating that sort of armor to want to attack them and eat them. Have we got some insights into what was eating these animals?

Shundong - We are uncertain at what species ate this group, because you look at these creatures, they are fully covered by their plates. I don't think as many creatures were larger than this.

Chris - And has anyone found anything like this anywhere else? You've got this from this particular part of Asia, but have you got anything like this anywhere else?

Shundong - Similar species have been found in Britain and in Germany. We are unsure which continent this group originated from, but what we can tell, based on the new discovery, we can tell that in early Jurassic, this group already spread very rapidly around the world.


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