Scientists Discover A Pregnant T. Rex, Bone Test Confirms

Posted: Mar 16 2016, 12:36am CDT | by , Updated: Mar 16 2016, 9:37pm CDT, in News | Latest Science News


Scientists Discover a Pregnant T. Rex, Bone Test Confirms
Credit: Mark Hallett

The bone fossil of a pregnant T. Rex may help identify the sexes of dinosaurs.

Researchers have discovered the fossil remains of a Tyrannosaurus rex dinosaur that lived in ancient Montanan 68 million years ago. 

Researchers believe that the creature was a mother-to-be and may hold the key to identifying the sexes of theropods or meat-eating dinosaurs. That would make it a major breakthrough in the field of paleontology since researchers find it difficult to determine the sex of a dinosaur most of the time.

Researchers from North Carolina State University examined the fossil remains of an extinct T. rex and found a gender specific reproductive tissue called medullary bone in the femur. 

The medullary bone is a special tissue that is found only in female birds and also only during the period when they are laying eggs. The fossil was discovered back in 2005, but only recently researchers were able to confirm that the tissue is medullary bone.

“All the evidence we had at the time pointed to this tissue being medullary bone. But there are some bone diseases that occur in birds, like osteopetrosis, that can mimic the appearance of medullary bone under the microscope. So to be sure we needed to do chemical analysis of the tissue.” Mary Schweitzer, a paleontologist from NC State and lead author of the study, said.

Ostepertosis can make a bone dense and may look identical to medullary bone. However, medullary bone is chemically distant from a bone with osteopetrosis. It contains a substance called keratan sulfate which is not found in any other bone. 

When researchers conducted a number of tests on the fossil sample and compared the results with the medullary tissue from ostrich and chinken bone, they found similarities and confirmed that the tissue was a medullary bone indeed that remained intact with the fossil tens of thousands of years since the death of the predator.

Since theropod dinosaurs like T. rex evolved into modern birds, the finding will not only help find out gender differences but could also shed light on the evolution of egg laying in modern-day birds.

“We know next to nothing about sex-linked traits in extinct dinosaurs. Dinosaurs weren’t shy about sexual signaling, all those bells and whistles, horns, crests and frills and yet we just haven’t had a reliable way to tell males from females,” said co-author Lindsay Zanno. “Just being able to identify a dinosaur definitely as a female opens up a whole new world of possibilities. Now that we can show pregnant dinosaurs have a chemical fingerprint, we need a concerted effort to find more.”

The details of the study were published in journal Scientific Reports.

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Hira Bashir covers daily affairs around the world.




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