Shu! What acute hearing you have, little Frankenstein creature
Digitally reconstructed prehistoric bird skull answers questions for Wits scientists
Hunting for prey under the dark cloak of night is no mean feat, which is why only a handful of the tens of thousands of bird species on Earth hack it.
Now, thanks to an extraordinary discovery by scientists at the Evolutionary Studies Institute at Johannesburg’s Wits university, we know that a more than 65-million-year-old dinosaur, from which birds descended, was able to do just that.
Called Shuvuuia, the tiny being lived in the Mongolian desert and was somewhat of a Frankenstein creature.
Wits described it as “among the most bizarre of all dinosaurs”, with its small birdlike skull, “weightlifter arms, with a single claw on each hand”, and long roadrunner style legs.
“This odd combination of features has baffled scientists since its discovery in the 1990s,” said the university.
But the part of this anatomical pastiche that grabbed the attention of Dr James Neenan was the lagena.
This is the organ that processes incoming sound information (called the cochlea in mammals) and there is a relationship between its length and the ability to hear well, as referenced by the fact that the barn owl, which can hunt in complete darkness using hearing alone, has the proportionally longest lagena of any bird.
The genesis of this huge discovery was when Neenan was doing a digital reconstruction. “As I was digitally reconstructing the Shuvuuia skull, I couldn’t believe the lagena size ... I called Prof Choiniere to have a look. We both thought it might be a mistake, so I processed the other ear. Only then did we realise what a cool discovery we had on our hands!”
Prof Jonah Choiniere, the joint first author of the study, had formerly been Neenan’s postdoctoral supervisor.
Now the two men stood together in amazement at what they saw.
“I couldn’t believe what I was seeing when I got there — dinosaur ears weren’t supposed to look like that,” said Choiniere.
The study that details this was initiated to “investigate how vision and hearing abilities of dinosaurs and birds compared”, said Wits.
The international team of researchers used CT scanning and detailed measurements to collect information on the relative size of the eyes and inner ears of nearly 100 living bird and extinct dinosaur species.
From their research they hypothesised that, like many desert animals, Shuvuuia foraged at night using superb hearing and vision to find prey in the dark, prey that consisted mainly of insects and small mammals.
Its long legs were then likely an adaptation that enabled it to “run their prey down”, while the strong forelimbs could pry the prey “out of burrows and shrubby vegetation”.
To assess vision, the team looked at the scleral ring, a series of bones surrounding the pupil, of each species. From this they were able to determine how large the creatures’ pupils could open and thus, how much light could come in.
“The team found many carnivorous theropods, such as Tyrannosaurus and Dromaeosaurus, had vision optimised for the daytime, and better-than-average hearing presumably to help them hunt,” the university said.
But the real outlier was Shuvuuia, which had extraordinary hearing and night vision.
Its eyes had “some of the proportionally largest pupils yet measured in birds or dinosaurs”, said the scientists of this chickensized anomaly.
“Nocturnal activity, digging ability and long hind limbs are all features of animals that live in deserts today,” said Choiniere, “but it’s surprising to see them all combined in a single dinosaur species that lived more than 65 million years ago.”- Sunday Times Daily