SAMSON: The Colossal T. rex Discovery

Now on exhibit through January 2, 2011 

A magnificent 40-foot fossil of one of Earth's most fearsome carnivores is now on display in the Earth Science Hall. The 66-million-year-old skeleton known as SAMSON* is one of the most complete Tyrannosaurus rex skeletons in existence. 56% of SAMSON's original bones, including the nearly complete skull, are on exhibit. SAMSON is smaller but close in length to the T. rex known as Sue, the largest T. rex yet discovered. SAMSON will be on display through December, 2010.

History

Mike Zimmershied discovered SAMSON in 1987 on his father's ranch south of Buffalo, South Dakota. The site was fully excavated in 1992. SAMSON, which was recently sold to a private buyer through Bonhams & Butterfields Natural History Department, is on loan to OMSI through a private donor and with the support of local supporting sponsors Comcast, the Science Channel, and Discovery Education. 

The Skeleton

SAMSON includes 170 original bones of the 300 in a full Tyrannosaurus rex skeleton. 56.7% complete by bone count, Samson is believed to be the third most complete T. rex skeleton ever discovered. SAMSON has arguably the best preserved T. rex skull. Too heavy to mount on the skeleton, Samson's real fossil skull is displayed in a case along with 22 teeth found scattered around the skull. 

In life, SAMSON measured approximately 40 feet in length and could have looked into a second story window. Its massive skull and powerful serrated teeth could bite through the leg bone of any other dinosaur of its time. The circumference of the femur tells us that SAMSON weighed about 6 tons, compared to the 7 ton Sue, the largest Tyrannosaurus rex discovered to date. Most likely a very skilled hunter with binocular color vision and an extremely sensitive sense of smell, this colossus, like other adults of its species, lived as an apex predator of the Late Cretaceous Period.

Pathologies: Evidence of Healed Injury and Disease

Although it is not possible to directly observe the behavior of extinct animals, the study of pathologies (evidence of healed injuries or disease) in their skeletons offers paleontologists glimpses of ancient behavior. SAMSON has retained a host of pathologies in its bones that can help us understand what it must have been like to be the reigning predator 66 million years ago.

Some of the most frequently encountered injuries to tyrannosaur skeletons are fractured ribs. Other traumas may include broken bones, calcified hematoma, pseudoarthrosis, osteomyelitis, and tumors.

SAMSON's skull has several healed puncture wounds, most notably a healed injury in front of the left eye. These most likely came from bite wounds from other Tyrannosaurus rex. Other injuries include fused tail vertebrae and extra bone growth on the dorsal spine which indicate an overload of weight upon the tail. The back of SAMSON's head also shows severe trauma with evidence of punctures and an active bacterial infection. 

An unknown species?

One of the most significant aspects of the skeleton known as SAMSON is that it may belong to a small subset of North American Tyrannosaurus specimens that may represent a new - as yet unnamed - species.

SAMSON is one of only four specimens whose skulls show substantial variation from the holotype of Tyrannosaurus rex. Differences in the tooth counts and the proportions of the skull have led some researchers to conclude that these specimens are likely something new. Unlike other skeletons, SAMSON has been prepared and conserved with modern methods and materials, and is the ideal specimen to test this hypothesis.

Samson and NASA

In 2005, SAMSON's skull was sent to NASA for examination using their high-tech x-ray equipment. The Marshall Space Flight Center used their X-ray Computed Tomography (CT) scanner to provide detailed cross-section images of the skull. Such detail helped experts better understand the anatomy and lifestyle of the Tyrannosaurus rex.

Resources:Samson - Tyrannosaurus X? and Evidence of Healed Injury and Disease in the Tyrannosaurus Called Samson by Peter Larson, Black Hills Institute of Geological Research.

* SAMSON is a trademark and service mark for TREX SAMSON, LLC. OMSI is an official licensee.