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Sexual Identification of A Rex Fossil
Rollie Hawk writes "The Tyrannosaurus rex has long been the darling of science fiction dinosaurs and has one of the most well-known skeletal designs among extinct creatures. But while even the most casual dinosaur enthusiast can identify the T. rex, until recently the sex of individual specimens was not discernable. Though dinosaurs are most known for their traits shared with modern reptiles, it is their kinship with birds that has finally revealed the sex of a T. rex fossil. To prepare for egg production, female birds develop a thick layer of medullary bone in their long bones, which acts as an extra source of eggshell calcium. According to Dr. Mary H. Schweitzer of North Carolina State University, the 'tyrant lizard king' appears to do the same thing. She explains that 'dinosaurs produced and shelled their eggs much more like modern birds than like modern crocodiles.'"
This is a cool achievement, but it does have limitations: (from the article)
"This discovery will not enable paleontologists to determine the sex of all dinosaurs because medullary bone is present only during the egg-laying cycle. But when present, it at least enables scientists to say that a particular example is female.
Not every museum may want to check the sex of its specimens because it requires cutting a long bone in half, said Horner, a co-author of the paper with Schweitzer.
Even then, finding medullary bone is a long shot, Schweitzer said. First the dinosaur has to be an ovulating female. It also has to die before it has finished laying eggs and has to be fossilized. Finally, that fossil has to be found by humans."
Unfortunately, this only means that a few specimens of them can be identified. It says that it's a damaging procedure, can only be used to determine femaleness and also, only works in a few cases.
It also might be interesting to know that this particular dinosaur specimen was also the first specimen they were able to recover soft tissue from a dinosaur.
"Real programmers don't comment their code. If it was hard to write it should be hard to understand."
In Jurassic Park the dinosaurs obtained that ability via frog DNA that was spliced in to fill the missing segments. In real life, we have no idea if they could do that or not. There's some likelyhood given the gender issues with birds, but we don't have complete DNA *or* intact specimens to even begin to guess.
link is here: http://www.npr.org/templates/story/story.php?story Id=4677825
I heard about it this morning. It sounds better over coffee.