Tank-like physique, bristling with body armour and a collar of spikes the length of golf clubs, Spicomellus afer looks more like a Pokémon creation than a living creature. This bizarre dinosaur roamed the flood plains of what is now north Africa 165m years ago, palaeontologists have revealed.
The fossil, the oldest known ankylosaur specimen, was unearthed near the central Moroccan town of Boulemane. Its extravagant armour has confounded existing theories of how the ankylosaurs, a major group of plant-eating dinosaurs, evolved.
“It’s absolutely bristling with spikes all over its body,” said Prof Richard Butler, of the University of Birmingham and the project co-lead. “It has these incredibly distinctive spikes around the neck – an armoured collar that is absolutely enormous and totally out of proportion to the rest of the body, smaller spikes projecting out of the ribs, and at the end of its tail it would have had some kind of weapon.”
The dinosaur’s anatomy was so outlandish that piecing together the body plan from the incomplete jumble of fossilised bones was not an easy task.
“We put all the armour out on a table and tried to figure out where, most logically, it would fit,” said Butler.
Ankylosaurs span the mid-Jurassic to the late Cretaceous epoch, when an asteroid crash-landing wiped out the majority of species, and are characterised by a squat, slow-moving and heavily armoured physique.
“They’re probably a bit dim-witted as they have relatively small brains, but they’re very successful,” said Butler. “They’re around for about 100m years.”
Spicomellus afer, now the earliest known example of the group, would have been around 4m in length and weighed around two tonnes. The fossil is missing the end of the tail, but fused vertebrae suggest that it would have culminated in a club-like structure, presumably used as a weapon to lash at rivals or predators. This suggests that adaptations for tail weaponry evolved around 30m years earlier than previously thought.
The more modest body armour of later ankylosaurs is typically interpreted as having evolved as a physical defence. The sheer extravagance of Spicomellus’s spikes, which would have protruded through tough skin, is more suggestive of dominance or mating displays, the researchers concluded.
“When you see the neck collar of this thing, it seems like total overkill,” said Butler. “It does seem like the kind of thing that would’ve complicated its life.”
A source of frustration is that the quarry where Spicomellus was excavated has been targeted by fossil hunters. The research relied on around half of the skeleton, which is held at the Dhar El Mahraz Faculty of Sciences in Fez, but fossilised bones believed to belong to the same specimen have been marketed online for up to £10,000, said Butler.
“There’s a huge problem with fossil poaching in Morocco,” he said. “Bits of this specimen have been for sale in the market in Europe and North America. There’s probably a significant amount [of the specimen] that has gone on to the market, often purchased by wealthy individuals. It’s quite a sad aspect of this story.”