A newly discovered dinosaur species made up for its diminutive size with the most flamboyant of styles we have so far seen from an ancient fossil. The researchers who identified its combination of fur, feathers and spine-like protuberances think it could teach us about the evolution of display in birds, including such famous examples as the peacock’s tail.
Feathers and even scales don’t fossilize nearly as well as bones or teeth, which is why we are still debating which dinosaur species had them and which didn’t. So, it is particularly astonishing that the only known fossil of the species newly named Ubirajara jubatus preserved normally perishable features like a thick mane running down its back.
The specimen also has fur-like bristles on its arms. However, the most remarkable feature of this long-lost beast are the long spikes that stick out from its shoulders. Professor David Martill of the University of Portsmouth, one of the authors of the paper describing U. jubatus in Cretaceous Research, refers to these as ribbons, but that may imply they were floppy. Instead the authors think they were probably stiff and used either to frighten off predators, intimidate rivals or woo mates, possibly all three. The closest resemblance the authors can think of is to the elongated display feathers of the birds-of-paradise, but the authors call the similarity “superficial”.
The “ribbons” are like nothing we have seen before, neither feathers, scales or fur, although they were probably made of keratin, like mammals’ hair and fingernails. Martill noted in a statement that keratin is much better than bone for display purposes, being “Less costly for a body to produce, it's also lightweight, flexible and can be regularly replaced if damaged.”
Combined with the likelihood that U. jabatus’ back muscles could cause the mane to stand up when required, this is one dinosaur that didn’t let being the size of a chicken prevent it from making quite an impression.
"We cannot prove that the specimen is a male, but given the disparity between male and female birds, it appears likely,” Martill said. In other words, all this fancy attire probably evolved in large part to impress potential sexual partners. "Given its flamboyance, we can imagine that the dinosaur may have indulged in elaborate dancing to show off its display structures," Martill added.
On the other hand, the U. jubatus specimen appears to come from an individual that was not yet mature. This is surprising, because in birds the showiest outfits are usually restricted to adults – the young benefit more from plumage less likely to attract predators' attention.
U. jubatus was extracted from 110 million-year-old rocks in Brazil’s Crato Formation and represents the first time a non-avian dinosaur from Gondwana has been found with preserved skin. Such a find is extraordinary enough, considering some of its features have never been seen before and others represent the oldest examples ever found. Adding to its remarkable nature, this is the first evidence of this family of dinosaurs in South America – its nearest known relatives appear to be from Europe in the form of the older genus Compsognathus.
The genus name means “Lord of the spear” in the language of the Tupi people of the region, while jubatus comes from the Latin for maned.