When we talk about the evolution of dinosaurs, the first ones that come to mind (almost automatically) are the T-Rex, the Velociraptor, or the Ankylosauria. However, there are many more species that once inhabited our planet and deserve mention and analysis. This is the case of the dinosaur Spicomellus afer, which lived in the region that today corresponds to Morocco during the Middle Jurassic period. Its remains have been found in the Atlas Mountains, near Boulemane, and it has been classified as the oldest known member of the armored ankylosaurs. A complete curiosity for paleontology, as it is one of the dinosaurs that shows a bony armor never before seen in another species.
According to Richard Butler, vertebrate paleontologist at the University of Birmingham and co-leader of the research on Spicomellys afer, he came to define this armor as ‘horrifically strange.’ The researchers have linked this shell to a function more related to courtship or mating, as it would not be practical for anything else. Susannah Maidment from the Natural History Museum in London explained the impracticality of this armor and the rather ‘passive’ uses it could have.
Spicomellus afer
Spicomellus afer is the only species that has been known and belongs to the genus Spicomellus. It is an ankylosaur that lived between the Bathonian and Callovian, approximately 169 to 164 million years ago, during the Middle Jurassic in what is now the African continent. According to Richard Butler, the vertebrate paleontologist and co-leader of the research conducted from the University of Birmingham in England, “The armor of Spicomellus is eerily strange, unlike any other dinosaur – or any other living or dead animal – that we have discovered”.
Why is it so peculiar?
In addition to being one of the largest dinosaurs, measuring approximately 13 feet in length and weighing 2 tons, Spicomellus afer was described as a crouching, herbivorous dinosaur. But what really caught the attention of researchers and paleontology in general was its bony armor. As Butler defines it, “Not only did it have a series of sharp, long spikes on each of its ribs – unknown elsewhere among animals – but it also had spikes the size of golf clubs protruding in a collar around its neck.”
The supposed evolutionary assumptions that had been made so far were challenged when they analyzed the collar of this species. Its vertebrae form a ‘handle’ structure, which had only been seen in ankylosaurs with tail clubs, placing the emergence of tail weapons 30 million years ago.
What purpose did this armor serve?
The opinion of different paleontologists and researchers is rather unanimous when it comes to explaining the function of this spiky armor. According to Butler, “The armor undoubtedly had some defensive function, but it is hard to imagine how the one-meter-long spikes around the neck were used for defense. They seem like enormous excesses.” The use of the spikes has been attributed to functions such as displaying to females, as happens with peacocks or deer. These types of practices are more related to sexual signals, mating, and evolutionary purposes.
According to Susannah Maidment of the Natural History Museum in London, “they could have been used in courtship or territorial displays, or to fight against members of the same species during competitions for mates. The armor of Spicomellus is totally impractical and would have been a bit cumbersome in dense vegetation, for example. So we believe it is possible that the animal developed such elaborate armor for some type of display, perhaps for mating”.
