Fossil hunters have unearthed remnants of the oldest – and probably weirdest – ankylosaur known so far from a site in the Middle Atlas mountains in Morocco.
The remains of the heavily armoured animal are extraordinary in being the first to have defensive spikes that are fused to the skeleton, a feature researchers say is unprecedented in the animal kingdom.
“It’s totally, totally weird,” said Dr Susannah Maidment, a palaeontologist at the Natural History Museum in London. “Normally when we see armour in stegosaurus and ankylosaurs, the dermal armour is embedded in the skin, not attached to the skeleton. In this case, it’s not only in contact with the skeleton, it’s fused to the ribs.”
Researchers at the museum obtained the fossil from a private collector for an undisclosed sum. They originally suspected the bones might belong to a new species of stegosaur they identified from the same region in 2019, but microscopic analysis of thin sections of the fossil revealed distinctive patterns of fibres unique to ankylosaurs.
The discovery was so unusual that scientists wondered whether the fossil might be a fake, but further inspection using a CT scanner found no signs that it had been constructed or tampered with.
The fossil dates to the middle Jurassic, about 168m years ago, suggesting the animal was one of the earlier ankylosaurs to roam the Earth. Beyond ranking as the oldest ankylosaur fossil known so far, it is also the first to be found in Africa.
Maidment said the animal could be an early ankylosaur from which others evolved, or an entirely new lineage. Details are published in Nature Ecology and Evolution.
Ankylosaurs – the name means “stiff lizard” – were large, herbivorous relatives of the stegosaurs. They sported heavily armoured skulls, spiked bodies and clubbed tails. The animals, which could grow to seven metre-long and weigh four tonnes, are mostly known from US and Canadian fossils dating from 74 to 67m years ago. The new fossil suggests that long before then, the creatures might have lived around the globe.
The fossil is now part of the collection at the Natural History Museum where researchers will continue to study the remains. Maidment said the hope was to work more closely with collectors in Morocco, and colleagues at the University of Fez, so more detailed information can be gathered on fossils from the Middle Atlas mountains, and to establish a specialised laboratory so that future finds can be studied in Morocco.