Overlooked fossil spread first feathers

A new look at a fossil that had been lying in a drawer in Moscow for nearly 30 years has uncovered the oldest known feathered animal, says a team of U.S. and Russian researchers.

Did feathers sprout from the 220-million-year-old reptile Longisquama insignis? Science

First honors go to the 10-inch-long, lizardlike Longisquama insignis, which is not a dinosaur itself but a related ancient reptile, say Terry D. Jones of Oregon State University in Corvallis and eight colleagues. It sported six to eight pairs of long, narrow feathers on its back, the researchers argue in the June 23 Science. The creature didn’t fly but may have been able to glide from tree to tree, they suggest.

Longisquama dates from some 220 million years ago, at least 75 million years before Archaeopteryx, the first known bird, the researchers note. They don’t claim that Longisquama gave rise to birds, explains coauthor Alan Feduccia of the University of North Carolina at Chapel Hill. However, he says, the fossil “points toward the right time to look for the ancestors of birds.”

That’s an inflammatory statement in the excitable world of bird-origin theorists (SN: 8/23/97, p. 120). What Jones calls “a vocal majority” traces birds to theropod dinosaurs, which include the celebrity velociraptors of Jurassic Park.

For example, Alan Brush of the University of Connecticut in Storrs says, many dinosaur traits fit neatly into a family tree branching into birds. “There’s so much morphological evidence,” he says.

The coauthors of the new paper read much like a Who’s Who of the opposing camp, which seeks bird ancestors more ancient than the dinosaurs. Feduccia points out that the most birdlike theropods date from 70 million years or so after Archaeopteryx. “You can’t be your own grandmother,” he teases.

The standard response to his objection, that the theropod lineage could have reached far back, seems “like a real stretch in this case,” Feduccia retorts.

A related debate flares over what gets called a feather. When Longisquama was unearthed in Kyrgyzstan in 1969, a Soviet paleontologist declared that the long structures on its back are featherlike scales.

In the 1990s, coauthor Larry D. Martin of the University of Kansas in Lawrence lobbied for the intriguing specimen to visit the United States in a traveling exhibit. Jones and coauthor John A. Ruben, also of Oregon, got their first look when the exhibit visited a mall in Kansas City. Wowed by the supposed scales, they set up an impromptu lab in an abandoned store and pored over the fossil almost all night.

After more study, the research team deemed the structures “nonavian feathers.” The scientists note that the central rib gives out offshoots, just as a modern feather’s shaft does, and the base looks like a feather’s end, or calamus.

The fossil’s featherlike fronds seemed to have developed in a sheath, as modern feathers do. In one place, the fossil sheath had chipped open, revealing what seem to be offshoots about to unfurl. Also, the whole structure arises from one insertion point, just as a bird’s feather grows from a follicle.

John H. Ostrom of Yale University, the father of the modern proposals that dinosaurs led to birds, calls the paper “very exciting” but wants to examine the fossil himself.

Brush sounds skeptical for the moment. “It looks like a feather, but so does a fern. So do echinoderms,” he notes.

He, Ostrom, Martin, and their colleagues examined feathery features on dinosaurs recently unearthed in China (SN: 5/3/97, p. 271). He cautiously pronounces the features “protofeathers,” simple structures that might—or might not—have led to modern feathers.

On these points, feathers will probably continue to fly, but there is some agreement. “There’s no question that birds and dinosaurs are related,” Jones says. “It’s just a question of where you put Grandma.”

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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