Paleontologists have discovered a 99-million-year-old feathered dinosaur tail preserved in amber. PHOTO: ROYAL SASKATCHEWAN MUSEUM (RSM/ R.C. MCKELLAR)
Paleontologists have discovered a 99-million-year-old feathered dinosaur tail preserved in amber they say could help them better understand how feathers have evolved since the time of the dinosaurs.
Over the past two decades, the idea that some dinosaurs had feathers has become widely accepted. Still, feather structure has been difficult to study since feather remains typically get crushed as fossils are formed in rock. Amber fossils, like the newly discovered one, preserve feathers much better, allowing scientists to study the plumes in greater detail.
The researchers stumbled onto the fossil at an amber market in Myanmar, where it was destined to be turned into jewelry, according to the researchers, who described their findings Thursday in the journal Current Biology.
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The team used microscopes and CT scans, similar to those used in medical settings, to study the fossilized plumes and preserved muscle, skin and ligament tissue beneath them. Based on these analyses, they say the tail likely belongs to a Coelurosaur, a group of dinosaurs that includes Tyrannosaurus rex and modern birds, and that it might have come from a juvenile.
Scientists think the feathered tail may have belonged to a Coelurosaur, a group of dinosaurs that includes Tyrannosaurus rex and modern birds. PHOTO: CHUNG-TAT CHEUNG
There is a big debate over how feathers evolved. For instance, it isn’t entirely understood how modern ones came to have a main shaft, barbs that branch off that shaft, and finer barbules, filaments that project from the barbs. Models based on modern birds are inconclusive about whether feathers developed a shaft and then branches, or if barbs and barbules existed first and fused into a shaft, said Ryan McKellar, a curator at the Royal Saskatchewan Museum, who worked on the new research.
“The feather shaft is one of the things that is necessary for forming flight feathers,” Dr. McKellar said. “If we know the path taken to get to a shafted feather, it might shed some light on the function of the first feathers with branching structure.”
The feathers described in the study lack a well-developed shaft.
“Studies of feather sections…in modern birds have pointed toward barbs and barbules existing first, [and] the new amber specimen adds some support for this idea from the fossil record too,” Dr. McKellar said.
However, it might be too early to draw final conclusions because researchers still need to uncover more fossils like this one to get a complete picture of dinosaur feather evolution, according to Mark Norell, a researcher at the American Museum of Natural History who wasn’t involved in the study.
“Feathers are really diverse,” he said. “For a single bird there might be 10 types.”
Scientists also have to be cautious about how much they conclude from CT scans, Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum in Los Angeles who wasn't involved in the research, said. It’s tricky to image amber fossils because of their opaqueness and density.
“It’s still a really interesting discovery,” Dr. Chiappe said. “We know that those kinds of dinosaurs were feathered and this is consistent with that.”
The researchers say they’re now working on a more detailed scan of the fossil.
