In the flesh

Alive as dinosaurs may seem to children, knowledge of them as living creatures is limited almost entirely to what can be learned from bones ...

Alive as dinosaurs may seem to children, knowledge of them as living creatures is limited almost entirely to what can be learned from bones that have long since turned to stony fossils. Their soft tissues, when rarely recovered, have lost their original revealing form.

A 70-million-year-old Tyrannosaurus rex recently discovered in Montana, scientists reported on Thursday, has apparently yielded the improbable: soft tissues, including blood vessels and possibly cells, that 8216;8216;retain some of their original flexibility, elasticity and resilience.8217;8217;

In a paper being published on Friday in the journal Science, the discovery team said that the remarkable preservation of the tissue might open up 8216;8216;avenues for studying dinosaur physiology and perhaps some aspects of their biochemistry.8217;8217;

8216;8216;Tissue preservation to this extent has not been noted before in dinosaurs,8217;8217; the team leader, Dr. Mary H. Schweitzer of North Carolina State University, said in a teleconference on Tuesday.

The scientists said that an examination with a scanning electron microscope showed the dinosaur blood vessels to be 8216;8216;virtually indistinguishable8217;8217; from those recovered from ostrich bones. The ostrich is today8217;s largest bird, and many paleontologists think birds are living descendants of some dinosaurs.

Schweitzer and other scientists not connected with the research cautioned that further analysis of the specimens was required before they could be sure the tissues had indeed survived unaltered. They said the extraction of DNA for studies of dinosaur genetics and cloning experiments was only a long shot.

But in a separate article in Science, Dr. Lawrence Witmer, a paleontologist at Ohio University who had no part in the research, said: 8216;8216;If we have tissues that are not fossilized, then we can potentially extract DNA. It8217;s very exciting.8217;8217;

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If the tissues are as well preserved as they seem, the scientists held out some hope of recovering intact proteins, which are less fragile and more abundant in DNA. Proteins might provide clues to the evolutionary relationship of dinosaurs to other animals and possibly help solve the puzzle of dinosaur physiology: whether they were warm-blooded.

The T-rex with the soft tissue was found in 2003 by a team led by John R. Horner, a paleontologist with the Museum of the Rockies at Montana State University. Horner is a co-author of the journal report, along with Jennifer L. Wittmeyer of North Carolina State and Jan K. Toporski of the Carnegie Institution of Washington.

The soft tissue was discovered inside a thigh bone which had to be broken so that it could be taken out of its resting place in deep in a remote corner of the Charles M. Russell Refuge, in Montana, by helicopter.