Londoners arriving at the Natural History Museum on Thursday, 26 June, were met by the institution’s first new dinosaur exhibit in years: a sleek, one-metre-long skeleton of Enigmacursor mollyborthwickae. Mounted on the Earth Hall balcony beside the museum’s Stegosaurus known as Sophie, the display lets visitors stand almost eye to eye with a creature that roamed what is now Colorado about 150 million years ago.
The specimen was unearthed in 2021 on private land within the Morrison Formation, swiftly offered for sale by a fossil dealer, and purchased for the museum with funds from philanthropists David and Molly Lowell Borthwick. “We were able to acquire it thanks to an amazingly generous private donation,” said Professor Paul Barrow of the Natural History Museum, according to the Sun. In gratitude, museum scientists named the animal Enigmacursor mollyborthwickae.
Measuring roughly one metre in length and half a metre in height, the skeleton is the most intact early small dinosaur of its kind yet found. Its unfused vertebrae showed it was a teenager that died before reaching full size. Palaeontologists Susannah Maidment and Barrow assembled the preserved neck, backbone, tail, pelvis, limbs, and feet, then reconstructed a missing skull by comparing it with similar dinosaurs such as Yandusaurus. “I think this animal was probably a teenager, but it may well have been sexually mature, so it might not have grown much larger,” said Maidment, according to New Scientist.
Long hind legs and oversized feet suggest a life built for speed on Jurassic floodplains threaded by rivers. “It walks on its hind legs only,” Barrow said, according to the Sun, adding that a rapid getaway likely served as its main defense against predators such as Allosaurus and large crocodiles. Maidment acknowledged that researchers still do not know how fast the dinosaur could run.
Early promotional material described the skeleton as a member of Nanosaurus, a poorly known genus named in the 1870s. Further study overturned that assumption, prompting the new genus name Enigmacursor—mysterious runner. Its balancing tail was probably longer than the rest of its body, BBC News reported, and it lived alongside giants such as Diplodocus and Stegosaurus. Separating Enigmacursor from the Nanosaurus catch-all should help researchers re-examine neglected bones and refine the picture of small herbivores from the period.
Smaller dinosaurs rarely attract the attention or price tags of their massive cousins. “Most of the focus has been on searching for the biggest and most impressive dinosaurs,” Maidment observed, according to the Independent. David Norman of the University of Cambridge told New Scientist that Enigmacursor represents “one of the rarities from further down the food chain of the dinosaur era.”
Maidment said the Morrison Formation was a floodplain fed by rivers spilling from highlands to the west. The youngster’s teeth indicate a diet of cycads and ferns, as flowering plants had yet to evolve. About the size of a Labrador but with disproportionately large feet, it likely darted between the legs of towering sauropods. “It was charging around in the shadows of behemoths like Diplodocus and Stegosaurus,” Maidment told New Scientist.
Although the skeleton is nearly complete, its top speed remains unknown. Mounted in a forward-leaning pose, the fossil suggests motion while leaving the actual velocity an open question.
Produced with the assistance of a news-analysis system.