Feathers Theory Takes Flight

Friday, July 02, 2004  
By STAN FREEMAN                                                                         Back to Archive Page         
sfreeman@repub.com

 A slab of shale 200 million years old in the fossil collection of Amherst College may show impressions that are the earliest evidence yet of a feathered dinosaur, perhaps an ancestor of the first bird.

That conclusion by a researcher from the Czech Republic, Martin Kundrat, will be detailed in the Journal of Experimental Zoology, Part B: Molecular and Developmental Evolution, scheduled for publication this month.

The dates when birds and feathers first evolved are among the most controversial and hotly debated topics in paleontology, and researchers are already taking sides on this latest claim.

Kundrat, a paleozoologist who spent the past year in residence at Wesleyan University in Connecticut, said scientists believe feathers evolved before flight did, and the fossil impressions represent a "preflight" feathered dinosaur, perhaps about 6 feet long, called a theropod. Many believe birds evolved from such dinosaurs.

"We are speaking really about the very early stages of feather evolution. The impressions look like filamentous structures, very thin long structures," he said.

"These kinds of structures are very similar to down feathers in early hatchlings of ostriches or emus. In both cases, this kind of feathering serves to keep heat produced by metabolism in the body," Kundrat said.

The Connecticut River Valley has proved to be among the world's richest sources of fossilized dinosaur tracks. In the 19th century, Amherst College president Edward Hitchcock collected nearly 1,300 rock slabs bearing impressions made by dinosaurs in the early era of their development, from 200 million to 190 million years ago.

The animals left footprints in mud or sand, which hardened in the sun and was then covered by new layers of mud or sand following a rainstorm. Over time the layers hardened into rock, such as shale or sandstone.

Hitchcock's collection in the Pratt Museum on the Amherst College campus is studied by researchers from around the world. The Pratt Museum has been closed to the public, except for scheduled tours, while preparations are made to move to a new building on campus, with reopening planned for 2007.

Scientists believe that after feathers evolved as a tool to regulate body temperature, they then evolved to aid in gliding from trees to the ground or in cushioning the landing. Eventually, they evolved for flight.

The earliest undisputed date for the appearance of feathers is about 145 million years ago, based on several fossilized remains of Archaeopteryx, the oldest known bird. However, there has long been a quest for evidence of feathers in dinosaurs prior to Archaeopteryx, which Kundrat believes the Amherst College fossil represents.

He contends the slab, called AC 1/7, shows impressions made by a dinosaur walking on two legs with three toes on each foot. As it rested momentarily in mud, it squatted, shifting its weight so its body feathers were pressed into the mud, the filaments creating a series of parallel lines beside the impression of the right foot.

Kundrat is not the first to make the claim that impressions on the slab show evidence of feathers. In 1996, Polish researcher Gerard Gierlinski examined the slab and came to the conclusion the impressions were made by feathers, although he did not speculate what type of feathers they were. Because the paper appeared in a Polish journal, it got little worldwide attention.

Hearing that Kundrat planned to revive the issue, Gierlinski made a trip to Amherst earlier this year to re-examine the fossil slab, said the museum's education coordinator, Steven A. Sauter.

"I ran into him in the museum and he is totally convinced, more than ever, that they are feathers. The issue is creating sides, and people are lining up on either side. When the paper gets published, there will be more people who will want to see it and make up their own mind," Sauter said.

Researchers on the other side of the issue include Paul E. Olsen, a noted Columbia University paleontologist, who has also examined the fossil.

"In my view, the 'feathers' represent delicate drag marks," he said.

Olsen believes the dinosaur rested momentarily on mud, which had a thin lacy mat of algae on its surface. When the animal began to move forward again, the matted mud clung to its body and was dragged, creating the striated marks Kundrat believes are feather marks.

Emma Rainforth, a geologist at Ramapo College of New Jersey who specializes in dinosaur footprints, also believes the marks are ripples in the mud created when the animal moved.

"Feather drag marks would have had a very different appearance compared to the traces exhibited by this specimen."

Kundrat has responded by asking how drag marks or disturbed mud could create lines that diverge, converge and cross each other. He believes only feathers could make such marks.

If Kundrat's theory is accepted, the Hitchcock fossil would be the first evidence of feathered dinosaurs to precede Archaeopteryx, predating the ancient bird by about 55 million years.

However, Kundrat is realistic about chances scholars will readily accept it as indisputable evidence.

"I expect there will be critics and skeptics because it is evidence based on impressions in rock," rather than the fossilized remains of an early feathered dinosaur, he said.

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