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Mary Schweitzer

Found soft tissue inside a T. rex thighbone, upending assumptions about what fossils can preserve.

Known for

Discovered soft, flexible tissue and blood vessel structures inside a 68-million-year-old Tyrannosaurus rex thighbone (2005), challenging assumptions about how completely fossilization erases original biological material.

Mary Schweitzer, a native of Helena, Montana, took an unusual path into paleontology: she earned a B.S. in Communicative Disorders from Utah State University in 1977 and only returned to science years later, after marrying and raising three children, when she took a paleontology course "for fun" taught by Jack Horner. That course led to a doctorate -- a Ph.D. in Biology from Montana State University in 1995, supervised by Horner himself -- and a career studying dinosaur tissue at the molecular level.[2]

In 2005, Schweitzer and her co-authors reported something that shouldn't have been possible: flexible, transparent blood vessel structures and soft tissue recovered from inside a demineralized thighbone of a Tyrannosaurus rex (specimen MOR 1125) unearthed in Montana's Hell Creek Formation in 2000. The bone also let researchers determine, for the first time, the sex of an individual dinosaur -- medullary bone tissue identified the animal as a female that had been carrying eggs. The findings reopened a long-settled scientific question: what, if anything, of an organism's original biology can actually survive tens of millions of years of fossilization.[1][2]

Now at North Carolina State University, Schweitzer's work has pushed toward recovering fragments of actual dinosaur proteins, including collagen, from fossil bone -- a claim that drew, and continues to draw, significant skepticism from parts of the paleontology community, given how implausible long-term protein survival was long assumed to be. Her lab continues to investigate exactly how, and how often, this kind of preservation happens.[1]

Timeline

Key dates, each traceable to a specific source.

  1. 1977

    Earned a B.S. in Communicative Disorders from Utah State University.[source]

  2. 1995

    Earned a Ph.D. in Biology from Montana State University, under Jack Horner.[source]

  3. 2000

    T. rex specimen MOR 1125 was unearthed in Montana's Hell Creek Formation.[source]

  4. 2005

    Published findings of soft tissue and blood vessel structures recovered from inside the T. rex bone.[source]

Legacy

Her soft-tissue findings reopened scientific debate over what can survive fossilization, and contributed early techniques toward recovering ancient proteins from dinosaur bone.

Sources

  1. Smithsonian Magazine
  2. Montana State University