Pterosaurs not only had feathers, they were also extravagantly colorful, scientists say.
That could mean that feathers, and vibrant displays of mate-seeking plumage, may have originated as early as the common ancestor of dinosaurs and pterosaurs, during the early Triassic period, about 250 million years ago.
Analyzes of the partial skull of a 113-million-year-old pterosaur fossil revealed that the flying reptile had two types of featherspaleontologist Aude Cincotta of University College Cork in Ireland and colleagues report April 20 in Nature. Above his head, the creature, believed to be tupandactyl imperatorit had simple whisker-like filaments and more complicated branching structures similar to those of modern bird feathers.
Because the soft tissues of the fossil were also well preserved, the team identified a variety of different forms of pigment-bearing melanosomes in both the feathers and the skin. Those shapes ranged from “very elongated cigar shapes to flattened plate-like discs,” says Maria McNamara, a palaeobiologist also at University College Cork.
Different forms of melanosome have been linked to different colors. Short, stubby spheroidal melanosomes are generally associated with yellow to reddish-brown colors, while longer forms are associated with darker colors, says McNamara.
The variety of melanosome geometries found in this tupandactyl the specimen suggests the creature may have been quite colorful, the team says. And that riot of color, in turn, suggests that the feathers weren’t just there to keep the creatures warm, but may have been used for visual cues, such as displays to attract a mate.
Scientists have argued over whether pterosaurs, The first true flying vertebrates on Earthwhether they had true feathers, or whether their bodies were covered with something more primitive and hair-like, called “pycnofibres” (Serial number: 7/22/21). If flying reptiles had feathers, they didn’t need them to fly; pterosaurs had fibrous membranes stretched between its long, sharp wings, much like those of modern bats (Serial number: 10/22/20).
In 2018, a team of researchers including McNamara reported that some of the fluff covering two fossilized pterosaur specimens was not just simple pycnofibers, but showed distinct, complex, branching patterns similar to those seen in modern pens (Serial number: 12/21/18). But some researchers have disputed this, saying that the branching seen in the fossils was a preservation artifactthe branching appearance created by overlapping fibers.
The new pterosaur specimen has “turned all that on its head,” says McNamara. In this fossil, “it’s very clear. We see feathers that are separate, isolated; it cannot be said that it is a superposition of structures”. Fossilized feathers show successive branches of constant length, extending along the axis of the feather.
And while previous pterosaur fossils described in 2018 had some preserved melanosomes, they were “intermediate forms, small short ovoids,” says McNamara. In tupandactyl, “for the first time we see melanosomes of different geometries” in the feathers. All of that adds up to a bright and colorful plumage.
“For me, these fossils close the case. Pterosaurs really did have feathers,” says Stephen Brusatte, a vertebrate paleontologist at the University of Edinburgh who was not involved in the study. “Not only were many famous dinosaurs actually big balls of fluff,” he says, but so were many pterosaurs.
many dinosaurs, particularly theropod dinosaursalso had colored feathers (Serial number: 7/24/14). What this study shows is that feathers aren’t just a bird thing, or even a dinosaur thing, but that feathers further evolved over time, Brusatte adds. And, since pterosaurs had wing membranes for flight, their feathers must have served other purposes, such as insulation and communication.
Dinosaurs and pterosaurs may have developed this colorful plumage independently, says McNamara. But the shared structural complexity of the pigments in both groups of reptiles makes it “much more likely that it was derived from a common ancestor in the early Triassic.”
“That’s a big new implication,” says Michael Benton, a paleontologist at the University of Bristol in England.
Benton, co-author of the 2018 paper, wrote a separate comment on the new study in the same number of Nature. If feathers arose in a common ancestor, Benton says, that would push the origin of feathers back about 100 million years, to about 250 million years ago.
And that could have other interesting implications, Benton writes. The early Triassic was a difficult time for life on Earth; were the aftermath of mass extinction at the end of the Permian that wiped out more than 90 percent of the planet’s species (Serial number: 6/12/18). If feathers evolved during that time, the insulating fluff, as well as warm blood, may have been part of an early arms race between reptilian mammalian ancestors called synapsids and the pterosaur-dinosaur ancestor.