[P]aleontologists have found 70-million-year-old amber preserving 11 specimens showing a wide diversity of feather types at that time.
One specimen of so-called proto-feathers had a single bristlelike filament and some simple clusters. Others were complex structures with hooklike barbules that act like Velcro; in modern birds, this keeps feathers in place during dives. Still other specimens revealed feather patterns for flight and underwater diving.
Preserved pigment cells encased in the amber, along with other evidence, suggested that the feathered animals had an array of mottled patterns and diffuse colors like modern birds...
The study focused on a 78-million-year-old, 15.4-foot-long (4.7-meter-long) adult Polycotylus latippinus plesiosaur fossil found in 1987. The fossil's abdominal cavity contains tiny bones—parts of a plesiosaur that hadn't been born by the time its mother died...
"Scientists have long known that the bodies of plesiosaurs were not well suited to climbing onto land and laying eggs in a nest [like dinosaurs]. So the lack of evidence of live birth in plesiosaurs has been puzzling," O'Keefe, a plesiosaur expert at West Virginia's Marshall University, said in a statement.
Live birth has been documented in other groups of ancient marine reptiles—such as the dolphin-like ichthyosaurs—but the study suggests plesiosaurs were unique, in that they generally gave birth to a single, large offspring, according to the study.
"These animals were incredibly fast, incredibly intelligent and some of them wielded very significant claws and sharp teeth," Dr. Lindsay Zanno of the New University of Wisconsin tells NPR's Scott Simon. Zanno led the dig team that made the discovery.
Zanno named the species Talos Sampsoni after her friend and colleague, Dr. Scott Sampson, also known as "Dr. Scott" on the television series, Dinosaur Train. Talos Sampsoni was feathered and about 5-feet long and about 2-and-a-half feet at the hips, Zanno says. "Definitely an overgrown vicious Labrador retriever-sized animal," she says.
Perhaps most exciting about Talos is its injured second toe, which has added to an existing debate on what troodontids did with the giant, sickle-like claw on that toe, study leader Zanno said.
Paleontologists have offered opposing explanations for the claw, for example that it helped troodontids climb, acted as a weapon in killing prey or fighting foes, or even enabled the dinosaur to clean itself.
...Instead, Talos may have wielded its claw like a puncturing device when hunting, for example by getting a foothold as the raptor scrambled up a larger animal's back, Zanno said.
Click here or here for an illustration of what Talos Sampsoni might have looked like and more discussion of its claw.