Juvenile Tyrannosaurus rex Tooth

Taxonomy

T. rex

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Avetheropoda
Family: Tyrannosauridae
Genus: Tyrannosaurus
Species: Tyrannosaurus rex
Author Citation Osborn, 1905

Geological Time Scale

Eon: Phanerozoic
Era: Mesozoic
Period: Cretaceous
Sub Period: None
Epoch: Late
International Age: Maastrichtian

Stratigraphy

Hell Creek Formation

Provenance

Acquired by: Purchase/Trade

Dimensions

Width: 8 mm
Height: 12 mm
Thickness: 4.5 mm

Location

Harding County
South Dakota
United States

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• hell creek
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• juvenile t rex
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• tyrannosaur
• tyrannosauridae
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• tyrannosaurus rex

Comments

Identification

Though smaller than many imagine T. rex teeth to be, this is indisputably one. It is characteristically robust, and has chisel-shaped denticles with similar denticle densities on each carina.¹ Those qualities support its identification as a Tyrannosaurid, and with the locality information confirming it originated from the Hell Creek formation, this must be T. rex.

Comments

Like most isolated theropod teeth, this is a shed tooth, likely lost during feeding.² This specimen has exquisite preservation with the enamel texture sharply retained as in life. It however has minor weathering with possible feeding wear at the tip, light root etching, and the base of the tooth has been lightly smoothed possibly by tumbling in an ancient river (enamel is harder so it wouldn't have weathered as much as other portions of the tooth). 

References

1. Smith, Joshua B. “Heterodonty in Tyrannosaurus Rex: Implications for the Taxonomic and Systematic Utility of Theropod Dentitions.” Journal of Vertebrate Paleontology, vol. 25, no. 4, 2005, pp. 865–87. JSTOR, http://www.jstor.org/stable/4524513. 

2. Fiorillo, Anthony R., and Philip J. Currie. “Theropod Teeth from the Judith River Formation (Upper Cretaceous) of South-Central Montana.” Journal of Vertebrate Paleontology, vol. 14, no. 1, 1994, pp. 74–80. JSTOR, http://www.jstor.org/stable/4523546.