Tyrannosaurus Specimen Profile II
Specimen: BMRP 2002.4.1
Size: ~6.5 meters, 680 kg
Details: Discovered by scientists and workers from the Burpee Museum, the young
tyrannosaur known as Jane has been a point of controversy ever since “her”
discovery. “She” is roughly half the overall length of a fully grown Tyrannosaurus
and much lighter weight, with long and slender legs. Studies indicate “she” was
roughly 11 years old at the time of death.
The identity of Jane (and other specimens like “her”) has been debated for some time
now. Some scientists believe Jane and others like “her” to be their own
species (Nanotyrannus lancensis), however most do not. Although, in 2013, Pete Larson saw
Jane as more identical to specimens CMNH 7541 and LACM 28471 than to adult Tyrannosaurus rex in
having a higher tooth count, large pneumatic foramen in the center of the
quadratojugal, T-shaped postorbital, and fused shoulder blade and pelvis. Yun
concurred in 2015 with the opinion of most workers that Nanotyrannus is a juvenile
T. rex, noting that a juvenile specimen of Tarbosaurus described by Tsuihiji et al.,
in 2011, also has a T-shaped postorbital. Thomas Carr has also made a number of
statements supporting the notion that Nanotyrannus is simply a juvenile
- Larson (2005). “A case for Nanotyrannus.” In “The origin, systematics, and
paleobiology of Tyrannosauridae”, a symposium hosted jointly by Burpee Museum of
Natural History and Northern Illinois University.
- Henderson (2005). “Nano No More: The death of the pygmy tyrant.” In “The origin,
systematics, and paleobiology of Tyrannosauridae”, a symposium hosted jointly by
Burpee Museum of Natural History and Northern Illinois University.
- Yun, C (2015). “Evidence points out that “Nanotyrannus” is a juvenile Tyrannosaurus
rex”. PeerJ. 3: e1052.
About the Author
Taylor McCoy is a paleontology enthusiast and volunteer at the Carnegie Museum of Natural History. He does fossil preperation at the Paleolab in the museum and field experience working in the Hell Creek Formation of Montana, where he worked alongside his wife. Taylor has written a few articles for I Know Dino and appeared in episode 316. You can follow him on Twitter @TM9380.