Jane is a Juvenile T. rex
Finally, the wait is over and it has been announced to the world that the theropod fossil at Rockford’s Burpee Museum is identified as an 11 year old Tyrannosaurus rex. She (of course we do not know the sex yet and the new medullary bone test (see below) may not show anything if Jane had not started laying eggs before she died) is now on display at the museum in all her glory. This is not a big surprise as Carr placed Nanotyrannus on the growth line of T. rex in a recent paper. Some had speculated that Jane was a Nanotyrannus. Compared to SUE she is 11 years old to SUE’s 28 years, she is 21 feet long compared to 42 feet, and she weighed an estimated 1,500 pounds compared to SUE’s 12,000 pounds (the paper reported 7 tons but we think SUE was closer to 6 tons). There are many differences in the T. rex as it grew. One of the most puzzling is the fact that the arm bones of both are about the same size even though there is a great difference in overall body size. Perhaps it did use them when younger, but did not need them when adult sized. The young T. rex also had more teeth than it would have as an adult. Jane had 17 in each dentary when an adult might have 10 or 12. In addition, they changed from curved and finely serrated for tearing flesh to become thicker for grinding as adults. Keep in mind that not all agree with Henderson’s findings. Phil Currie, Bob Bakker and John Horum still believe Nanotyrannus is a separate species. I’m sure there will be more to come.
T. rex Bone May Tell Sex
Additional bone histology work by Mary Schweitzer may show that the sex of a T. rex can be determined by the presence of medullary bone in the female. In birds there is a medullary bone layer inside the cortical layer or hard outer bone that is used by the
female as a source of calcium to make the eggshells. When the bird is done making eggs, this layer gets reabsorbed back into the outer bone. The bone of the T. rex was identical to that found in flightless birds like emus and ostriches. Mary earlier reported on soft tissue found within the broken femur of this same Montana T. rex. Jack Horner says he has 12 other T. rexes he hopes to have sexed and The Field is looking into sexing SUE as well. It may not work for all fossils because if it is female it has to have died in its ovulating years. This is exciting news indeed!!! And it adds another strong link of birds with theropods. (Schweitzer et al in Science Vol. 308/June 2)
A New T. rex from Utah
This first Utah T. rex is from the Upper Cretaceous North Horn Formation and was found in association with Alamosaurus sanjuanensis. This discovery in upland intermontane basin helps to show that T. rex was an ecological generalist that ranged a large geographic area. They have found about 17% of the animal with a few cranial elements, several vertebrae and partial elements from the pelvis and parts of the left leg. It appears to be about the same size as SUE. Some of the bones show pathologies. Although T. rex appears to have been the top predator all along the western side of the Western Interior Seaway, their prey varied with Alamosaurus and the ceratopsid Torosaurus in the more southern area and Triceratops and Edmontosaurus in the northern area. (Sampson & Loewen in JVP Vol. 25/2, June 2005)
Early Mammal with Poisonous Teeth – Bisonalveus
A 60 MY old mole sized mammal identified as Bisonalveus browni was being studied by a student for his PhD thesis at the University of Alberta in Edmonton. The mammal had been found in 1991 on an expedition by his professor Richard Fox near Blindman River near Red Deer and was stored without being studied. The species has been known since 1956 from partial skeletons. He noticed that the upper front canine teeth had long grooves on the whole length of the teeth. There is another larger mammal (without enough material for formal identification) from the same formation which shows this same characteristic. There are only 2 modern mammals with poisonous bites, certain shrews and a solenodon in the Caribbean. It is thought that large carnivores did not need poison to dispatch their prey while a smaller animal might benefit from the injection of poison to subdue and kill larger prey. (Scott et al in Nature)
Karen Chin Has New Book – “Dino Dung”
Karen Chin is the world expert on coprolites and is now working in Boulder Colorado and has published her first book geared to youngsters. As expected it is a good read and presents the material clearly and interestingly. The illustrations are by Karen Carr.
Molecular Preservation in Sauropod Eggshells in Patagonia
They have found the preserved remains of soft tissue within the eggshells found In Patagonia. They found fragments of biomolecules preserved when they were very rapidly mineralized so long ago. The organic compounds and antigenic structures are similar to those found in extant chicken eggshells. (M. Schweitzer, Chiappe et al in Proc. Roy. Soc. Biol B Vol. 272)
New Tool Makes Old Texts Readable
Many old papyrus documents have been dug up over the years but are in such poor condition that they can not be read easily. Experts feel that in 100 years they have deciphered only one percent of the total collection. Now with a new device from NASA they are ready to publish 2 pages of work by Sophocles and Archilochos of ancient Greece. And that only took a couple of weeks. The NASA device was used to map the surface of Mars and uses multispectral imaging. It can scan a page at several different wavelengths and then put them together to see the writing. It is news like this that keeps you hoping for the technology to answer more of our questions – especially in paleontology. (Hundley in Chicago Tribune, May 19)
Karen Nordquist, Paleontology Study Group
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