“It’s Pretty Unusual”: Oldest Known Member Of Ankylosaurs Is Also The Most Badass With “Wacky” 1-Meter Neck Spikes

The ankylosaurs were a very impressive group of dinosaurs covered in armored plates with clubs for tails (that may have sounded like birds), but we’ve just discovered that the oldest known member of the group may have also been the most badass. New fossils have revealed that an ankylosaur known as Spicomellus afer was covered in enormous spikes that were fused to its bones, some almost a meter (3.3 feet) long.

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“The armour of Spicomellus is unlike that of any other ankylosaur,” said study author and London Natural History Museum senior researcher Dr Susannah Maidment to IFLScience. “Other ankylosaurs have bony collars around their necks, but they are mostly flattish bands of bone or flattened pyramid-shaped osteoderms (bony plates embedded in the skin).”

These long spikes around its neck seem like massive overkill to deter a predator.

Dr Susannah Maidment

“Spicomellus has four spikes about 1 meter [3.3 feet] long each extending from a robust band of bone around its neck, which also bears a shorter, midline spike and two flattened, tear-drop shaped plates at each end. It’s totally wacky.”

Totally wacky is about right when you see the fossilized bones the team uncovered. In the photo below, you can see one of the 165-million-year-old fossils dating back to the Middle Jurassic that the team retrieved from an area we now know as the Moroccan town of Boulemane.

Spicomellus was first described back in 2021 from a rib bone. It marked an exciting discovery being the oldest known ankylosaur, and also the first one found on the African continent, but it only told part of the story.

Now, these new remains have revealed that these ankylosaurs had bony spikes fused onto all of their ribs, sticking out like pins from a cushion. This is totally unique not only to ankylosaurs, but to any other vertebrate species known to science, living or extinct. Some of these spikes measured just shy of a meter at 87 centimeters (34.3 inches) long.

We think that instead they may have been used for display purposes – maybe in courtship displays to attract a mate, or perhaps to deter a rival, a bit like a peacock’s tail or perhaps the antlers of deer.

Dr Susannah Maidment

So, what does one do with this extreme built-in body armor? It might have been more about love than war.

“We are in the very early stages of exploring the rocks in which Spicomellus was found, so we don’t yet know what meat-eating dinosaurs were living alongside it,” said Maidment. “We have found some big theropod (meat-eating dinosaur) teeth though, so there were definitely big predators.”

“These long spikes around its neck seem like massive overkill to deter a predator though, so we think that instead they may have been used for display purposes – maybe in courtship displays to attract a mate, or perhaps to deter a rival, a bit like a peacock’s tail or perhaps the antlers of deer.”

The other remarkable thing about this discovery is that it comes to us from the oldest member of its group. As study co-author Professor Richard Butler of the University of Birmingham told us, that’s not typically the way these things go.

Perhaps Spicomellus is a super weird one-off, or perhaps we’ve got much of what we thought we knew about the evolution of ankylosaurs wrong.

Professor Richard Butler

“Normally, early members of most groups of animals, including dinosaurs, aren’t particularly exceptional in appearance, and weird and wonderful features appear later in the group’s evolution,” Butler told IFLScience. “It’s pretty unusual that the oldest member known of a group – especially one such as ankylosaurs that survived for over 100 million years – has the most extreme adaptions that we’ve ever found in that group.”

“Perhaps Spicomellus is a super weird one-off, or perhaps we’ve got much of what we thought we knew about the evolution of ankylosaurs wrong.”

Fair play, Spicomellus. Gotta keep ‘em guessing.

The study is published in the journal Nature.