When Xing and colleagues later CT scanned the amber and analyzed its chemistry, even they were surprised by what they found: a dinosaur tail, residue of dinosaur blood and insects that likely scavenged on the deceased dino, which died about 99 million years ago. The discovery is reported in the journal Current Biology.
|Close-up of the 99-million-year-old dinosaur tail in amber. Scavenging insects can also be seen.|
Co-author Ryan McKellar of the Royal Saskatchewan Museum added, "This is the first time that skeletal material from a dinosaur has been found in amber. Previous finds in amber have included isolated feathers that may have belonged to dinosaurs, but without an identifiable part of the body included, their source has remained open to debate."
The researchers believe that a juvenile carnivorous dinosaur belonging to the Maniraptora clade (dinos closely related to birds) could have become trapped in tree resin and died, or passed on for other reasons before resin dripped on it and hardened.
|Recreation of a maniraptoran dinosaur that could resemble the individual whose tail became trapped in tree resin 99 million years ago.|
Persons added, "The little bit of tail comes from a dinosaur probably about the size of a robin. The shape of the tail vertebrae, which we can only see in X-ray images, indicates that the dinosaur was a two-legged carnivore. It may be a hatchling or possibly an extremely small species that's new to science. So little of the skeleton is preserved that we cannot tell."
The researchers could confirm that the tail comes from a dinosaur, and not a prehistoric bird, because of its structure. They explained that the tail is long and flexible, lacking a well-developed central shaft, known as a rachis. Keels of feathers run down each side. The structure of these feathers suggests that the two finest tiers of branching seen in modern feathers, called barbs and barbules, arose before a rachis formed.
"The development of the rachis allows feathers to form long, vaned shapes that are useful for more than just temperature, regulation, or visual signaling," McKellar said. "It provides feathers that are more useful in controlled flight."
Visible traces of pigmentation in the tail's plumage reveal that its upper surface was chestnut brown in color, while its underside was pale or white during the dinosaur's lifetime. The contrast must have been quite striking as the animal moved about.
|Illustration showing what the maniraptoran dinosaur might have looked like when alive and hunting for food.|
The researchers are now eager to see how more finds from Myanmar and surrounding regions might reshape our understanding of plumage and soft tissues in dinosaurs and other prehistoric animals.
Read more at Discovery News