Early Cretaceous Feathered Dinosaur Had ‘Bandit Mask’ and Striped Tail

Sunday, October 29, 2017

University of Bristol paleontologists and natural history artist Robert Nicholls have revealed how Sinosauropteryx prima — a small theropod dinosaur that lived about 125 million years ago (Early Cretaceous epoch) in what is now China — used its color patterning, including a bandit mask-like stripe across its eyes and a banded tail, to avoid being detected by its predators and prey. The research is published in the journal Current Biology.

“Far from all being the lumbering prehistoric grey beasts of past children’s books, at least some dinosaurs showed sophisticated color patterns to hide from and confuse predators, just like today’s animals,” said co-author Dr. Fiann Smithwick, from the School of Earth Sciences at the University of Bristol.

“Vision was likely very important in dinosaurs, just like today’s birds, and so it is not surprising that they evolved elaborate color patterns.”

To explore the color pattern of Sinosauropteryx prima, Dr. Smithwick and colleagues examined the remnants of pigmented feathers from the best-preserved specimens available.

By making comparisons among three specimens, they were able to confidently reconstruct the unique way that this dinosaur looked.

“The bandit mask was really amazing to discover. It’s a pattern seen in numerous living animals today,” Dr. Smithwick said.

Sinosauropteryx prima was also countershaded, meaning that its body was darker on top and lighter underneath.

The particular way it was countershaded further suggests that the dinosaur lived in more open habitats, not in the dense forest.

Once the paleontologists reconstructed the color pattern, they created 3D models of the dinosaur and photographed them under different lighting conditions to see where their coloration would have hidden them best from potential predators.

Their images show that Sinosauropteryx prima must have spent lots of time out in direct sunlight, not in the shade.

Sinosauropteryx prima fossils and interpretive drawings. The plumage distribution is mapped out across each specimen, with feathers shown in brown, internal soft tissues and pigment from the eyes shaded gray, and vertebrate stomach contents in light blue. Scale bars – 50 mm. Image credit: Smithwick et al, doi: 10.1016/j.cub.2017.09.032.

The findings are especially interesting in light of an earlier reconstruction by the team of the color patterns of Psittacosaurus, an early relative of the famed horned dinosaur Triceratops.

Those studies showed that Psittacosaurus was also countershaded, but in a manner suggesting that it lived in the forest.

The distinction between species suggests that the environment around China’s prehistoric Jehol lakes, where these dinosaurs lived, was unexpectedly diverse, hosting dinosaurs adapted to life in different environments.

“We have shown how a greater understanding of ancient environments can come from better understanding of the paleoecology of extinct animals through paleocolor reconstructions,” said study senior author Dr. Jakob Vinther, from the Schools of Earth and Biological Sciences at the University of Bristol.

“Both meat- and plant-eating dinosaurs had excellent vision; both needed to stay camouflaged.”

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Fiann M. Smithwick et al. Countershading and Stripes in the Theropod Dinosaur Sinosauropteryx Reveal Heterogeneous Habitats in the Early Cretaceous Jehol Biota. Current Biology, published online October 26, 2017; doi: 10.1016/j.cub.2017.09.032

Source: sci-news.com

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