Dinosaurs were much fluffier than thought: study

Dinosaurs were much fluffier than previously thought, according to researchers who have created the most accurate depiction of any dinosaur species to date.
Birds are the direct descendants of a group of feathered, carnivorous dinosaurs that, along with true birds, are referred to as paravians - examples of which include the infamous Velociraptor.
Researchers from the University of Bristol in the UK examined, at high resolution, an exceptionally-preserved fossil of the crow-sized paravian dinosaur Anchiornis - comparing its fossilised feathers to those of other dinosaurs and extinct birds.
The feathers around the body of Anchiornis, known as contour feathers, revealed a newly-described, extinct, primitive feather form consisting of a short quill with long, independent, flexible barbs erupting from the quill at low angles to form two vanes and a forked feather shape.

The observations were made possible by decay processes that separated some of these feathers from the body prior to burial and fossilisation, making their structure easier to interpret, researchers said.
Such feathers would have given Anchiornis a fluffy appearance relative to the streamlined bodies of modern flying birds, whose feathers have tightly-zipped vanes forming continuous surfaces, they said.

Anchiornis's unzipped feathers might have affected the animal's ability to control its temperature and repel water, possibly being less effective than the vanes of most modern feathers. This shaggy plumage would also have increased drag when Anchiornis glided.
The feathers on the wing of Anchiornis lack the aerodynamic, asymmetrical vanes of modern flight feathers, and the new research shows that these vanes were also not tightly-zipped compared to modern flight feathers.

This would have hindered the feather's ability to form a lift surface. To compensate, paravians like Anchiornis packed multiple rows of long feathers into the wing, unlike modern birds, where most of the wing surface is formed by just one row of feathers.
Anchiornis and other paravians had four wings, with long feathers on the legs in addition to the arms, as well as elongated feathers forming a fringe around the tail.
This increase in surface-area likely allowed for gliding before the evolution of powered flight.
The new piece represents a radical shift in dinosaur depictions and incorporates previous research.

"The novel aspects of the wing and contour feathers, as well as fully-feathered hands and feet, are added to the depiction," said Evan Saitta, from the University of Bristol's School of Earth Sciences.
"Most provocatively, Anchiornis is presented in this artwork climbing in the manner of hoatzin chicks, the only living bird whose juveniles retain a relic of their dinosaurian past, a functional claw," said Saitta.
"This contrasts much previous art that places paravians perched on top of branches like modern birds.
"However, such perching is unlikely given the lack of a reversed toe as in modern perching birds and climbing is consistent with the well-developed arms and claws in paravians," Saitta said.