September 22, 2016:
by Camouflage of the ‘parrot lizard' dinosaur is recreated using 120 million-year-old fossils
From fearsome spikes to clever colouration, plant eating dinosaurs had a variety of features to keep them safe from larger and more ferocious predators.
Now experts have reconstructed the colour patterns of Psittacosaurus, meaning ‘parrot lizard’, to reveal it had a light underside and darker colouring on top, to keep it camouflaged in forests, between 123 million and 100 million years ago.
Its colouring, known as countershading, is a common form of camouflage in animals today.
The beaked, feathered dinosaur had horns on either side of its head and long bristles on its tail.
An international team of scientists reconstructed the bizarre-looking, long-lost species’ patterns using a well-preserved fossil from China.
The fossil was found in the same rock strata where many feathered dinosaurs from the early Cretaceous had been discovered.
‘The fossil preserves clear countershading, which has been shown to function by counter-illuminating shadows on a body, thus making an animal appear optically flat to the eye of the beholder,’ said Jakob Vinther of the University of Bristol.
Innes Cuthill, also at the university, added: ‘By reconstructing a life-size 3D model, we were able to not only see how the patterns of shading changed over the body, but also that it matched the sort of camouflage which would work best in a forested environment.’
Countershading most likely served to protect Psittacosaurus against predators that used patterns of shadow on an object to determine its shape, just as humans do.
It was Vinther who realised that structures in the fossilised feathers previously thought to be dead bacteria were actually ‘melanosomes’ – small structures that carry melanin pigments found in the feathers and skin of many animals.
The experts were therefore able to make out the patterns of preserved melanin to reveal the animal’s colouring, which is described in the journal Current Biology.
They teamed up with palaeoartist Bob Nicholls to make what they claim is the most scientifically accurate, life-size model made of a dinosaur with its real colour patterns.
This enabled them to compare the extinct creature’s colouring to what they believe is optimal countershading, based on measured radiance patterns generated on an identical uniform grey model in direct and dappled light scenarios.
From this, they concluded the parrot lizard – so-called because of its bird-like beak – lived in a closed habitat such as a forest with a relatively dense canopy.
‘We were amazed to see how well these colour patterns actually worked to camouflage this little dinosaur,’ Vinther said.
The rock deposits in which the dinosaur fossil was found, include evidence for a forest environment based on plant and wood fossils.
However, Vinther said closely related species lived in Mongolia in an environment that would have resembled a savannah with much less vegetation, meaning they would probably have had different camouflage patterns too and so, the researchers predict, would have had different camouflage patterns to Psittacosaurus.
The researchers say that they would like to explore other types of camouflage in fossils and to use this evidence in understanding ‘how predators could perceive the environment and to understand their role in shaping evolution and biodiversity.’
http://www.dailymail.co.uk/sciencetech/article-3789265/Camouflage-parrot-lizard-dinosaur-recreated-using-120-million-year-old-fossils.html
|