There is much that stands out with Spicomellus. What made the researchers react is a large number of spikes that sat like a collar around the neck and continued along the body's sides all the way to the rear hip.
Normally for armored animals – everything from crocodiles to stegosaurs and ankylosaurs – the armor lies on the outside of the skin. But here the spikes are actually attached to the ribs, says Susannah Maidment, archaeologist at the Natural History Museum in London.
Spicomellus is an ankylosaur, the low armored dinosaurs that often had tails with clubs to defend themselves. It was described for the first time in 2021 by Maidment and some colleagues, based on a single rib found in the Moroccan Atlas Mountains. The dinosaur lived during the Jurassic period, and is the oldest known ankylosaur. The find in the Atlas Mountains is the first to be made in Africa.
Not all research colleagues were convinced of the research team's description of the dinosaur.
I never thought we would find anything more of it, without it being a complete fluke, an odd thing that we would never know more about, says Maidment.
Farmer made discovery
But a flash flood that passed through the excavation site, which resembles a kind of ditch, suddenly exposed a large number of fossils that a local farmer found.
When we got there, he pulled out all this from his house and spread it out on the ground. And we thought "good lord, this is incredible", says Maidment, who describes it as the highlight of her career.
– I looked at them and thought, I have never seen anything like it before. I did not even recognize some of the bones, what part of the anatomy I was actually looking at.
Moreover, she put her critics in their place.
It was a bit of revenge – and a massive relief.
Exaggerated spikes
The more complete skeleton reveals much more about Spicomellus. It was about four meters long and probably weighed more than a ton.
The entire tail has not been found, but fused tail vertebrae suggest that it probably had a weapon at the end of the tail.
The largest spike found is 87 centimeters long. They were probably intimidating to enemies, but were probably used mainly to impress. The same spikes have not been found on younger ankylosaurs that lived during the Cretaceous period.
We think they simplified their armor over time. They are more like pyramid-shaped plates, which are probably better armor. Spicomellus' spikes seem so exaggerated, says Susannah Maidment.
The study is published in Nature.
Gustav Sjöholm/TT
Facts: Dinosaur that stands out
TT
Spicomellus afer was described in a study in Nature in 2021, based on a single rib.
Fresher finds in the form of a more complete skeleton (including six ribs with spikes attached to the top, a collarbone with plates and two pairs of spikes and a pelvic shield with spikes) reveal more details of the dinosaur, which is the oldest ankylosaur discovered, as well as the first from Africa, according to the study from Natural History of London, University of Birmingham and the Moroccan Université Sidi Mohamed Ben Abdellah.
Spicomellus lived during the Jurassic period 165 million years ago in present-day Morocco. The study is published in Nature.
