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Nanotyrannus lancensis

Name Means: "Tiny tyrant" Length: 17 feet (5 m)
Pronounced: NAN-oh-tie-RAN-us Weight: 1 ton (900 kilos)
When it lived: Late Cretaceous - 60-65 MYA    
Where found:      


    Nanotyrannus was a small, but extremely dangerous little tyrannosaur.  Its head was about the length of an adult man's arm, but it housed a pair of large, forward-looking eyes that provided excellent binocular vision and depth perception. It could easily spot distant prey, then lunge forward, taking long, fast strides with its powerful hind legs. It was very agile and could abruptly change direction.  It was also fast and it has been estimated that he could run up to 30 kilometers an in short spurts.  A victim would have found it very difficult to escape.
    Nanotyrannus could grab its prey with its powerful jaws, sinking his curved eyeteeth into the body of his surprised victim. Like all tyrannosaurs, it had two very small front legs; they were finished off by two fingers that had strong claws. He and may have his arms and fingers to position the food for eating. Then again, the carnivore versus scavenger debate lingers on so it is possible that he fed on carrion, dead animals.
    Nanotyrannus is known from a single skull and jaw. The skull was originally thought to be that of an Albertosaurus, but significant differences were noticed years after it had been prepared and stored on a museum shelf.  The skull was re-prepared, studied and re-described by Dr. Robert Baker. Nanotyrannus had the honor of being the first dinosaur to be CAT scanned.  The skull is now housed at the Cleveland Museum of Natural History.
    Some paleontologists believe that Nanotyrannus is a juvenile Tyrannosaurus rex, partly because some of the skull bones are not fused, indicating an immature animal. A few paleontologists have suggested it may be a type of huge dromaeosaur (raptor). Nanotyrannus are the most primitive tyrannosaur. Its wedge-shaped skull, narrow beak, large orbits, forward-pointing parasphenoid, and infratemporal fenestra without any large rostral process of the quadratojugal and squamosal make it the most troodont-like and most ornithomimid-like tyrannosaur so far discovered.
   Those that argue that Nanotyrannus is a different species point out that Nanotyrannus had slim and razor-like teeth that were great for slicing through flesh. Tyrannosaurus  rex, by contrast, has teeth like railroad spikes—larger and rounder for piercing and puncturing prey and biting through bones. 


    In the fall of 1997, the Leonard and Arlene Zerbst family discovered a dinosaur fossil on their ranch in Niobrara County, Wyoming. The ranch is part of the Lance Creek fossil bed, where the fossils of many dinosaurs from the Late Cretaceous Period have been found. The following April 1998, it was excavated by the Black Hills Institute staff.
It was named by the Zerbsts "Kelsey" after their three-year old granddaughter, Kelsey Ann.  Kelsey is one of the three most complete Triceratops horridus skeletons known to science.  Kelsey is on display at the Children's Museum of Indianapolis.
   What makes Kelsey particularly interesting is that among its bones there were more than twenty Nanotyrannus teeth. This raised interesting questions. Since so many shed, or broken, "Nano" teeth were discovered with one skeleton, it seems unlikely that all came from the same individual.  It seems more probable that Triceratops was attacked by a packs of Nanotyrannus.  Or did Kelsey die of natural causes and the Nanotyrannus just happen along to scavenge on the already dead Triceratops
   Kelsey's discovery and preparation may help resolve the debate as to the true identification of Nanotyrannus since some researchers have maintained that this small carnivore is, in fact, a juvenile Tyrannosaurus rex. Since no juvenile or infant T. rex teeth have been discovered, some scientists have suggested that the more primitive dentition of Nanotyrannus lancensis is in reality that of a baby or juvenile T. rex. However with Kelsey's remains, a very small, 3/8 inch long crown of a tooth was discovered that has characteristics consistent with a baby Tyrannosaurus rex tooth. If this preliminary identification holds true, it may help prove Nanotyrannus as a valid genus. The possibility that a "Nany-pack" used hunting strategies very different from those of the small family-group hunting strategy postulated for Tyrannosaurus rex may bolster the argument for assigning Nanotyrannus its own genus.


     In June 2001, Michael Henderson, Curator of Earth Sciences at the Burpee Museum, led a dinosaur fossil hunting expedition to Montana's Badlands.  Volunteer dinosaur hunters Bill Harrison and Carol Tuck discovered a six-inch-long toe jutting out of the base of a 20-foot cliff face. From there, they noticed a cross section of a lower limb, and lower down, a foot and pelvis, which implied that there was a significant portion of the skeleton within the cliff. Henderson removed the toe and foot bone, marked the site, and returned nearly one year later in May 2002 with permits, shovels, and volunteers. They eventually unearthed a dinosaur they named, "Jane," after a museum benefactor.
    Over the next three years, as fossil workers carefully extracted each of Jane’s 145-plus bones from their field jackets.  Henderson examined them and compared them to the bones of tyrannosaur specimens held in museums across North America. At first, it seemed that Jane’s skeleton had a number of features that looked different from those of an adult T. rex. But as Henderson surveyed juvenile tyrannosaurid dinosaurs at other museums, he discovered that they had many of these same features.
    One of the features that initially set Jane apart from T. rex is what scientists call “tooth count.” With a total of 72 teeth, Jane has 12 more than the typical adult T. rex. However, after examining dozens of dinosaur jaws and discussing his findings with his colleagues, Henderson became convinced that T. rex lost teeth as it reached adulthood.  And, of course, there was Jane’s diminutive size. Just half the size of an adult T. rex, Jane could either be a full-grown small dinosaur or a half-grown big dinosaur.
     Furthermore, the new specimen is definitely not a juvenile, said Henderson, "It has a couple of fused vertebrae and the three pelvic bones are fused into one bone, which would only occur in an adult."  Then, one day, Henderson received an unexpected visit from Dr. Greg Erickson, a paleobiologist from Florida State University. Erickson had discovered a way to count growth rings inside of dinosaur bones to tell how old they were when they died. Henderson supplied him with a piece of Jane’s shinbone and, within a few months, Erickson had determined that, at the time of death, Jane was 11 years old—and still growing.  He concluded that rather than being an adult Nanotyrannus, Jane is a juvenile Tyrannosaurus rex.
    In any event, the discovery is a major accomplishment for a small museum.  The discovery is the Burpee Museum's first major dinosaur find.  The museum was established in 1941 as a Works Progress Administration project. It operated on a meager budget for many years.  It received a generous donation in the late 1990’s, which it used to open a new paleontology wing in 1999.  Since that year the museum has held an annual paleontology festival, where the world’s leading scientists give lectures on fossils.


    The true type of Nanotyrannus lancensis was based on an isolated skull found by Charles Gilmore in Montana during 1942. The skull was low with a long and narrow snout and has similar features to that of T. rex. It also had a stereoscopic view.  It was not found in in association with any other tyrannosaurid material.
    In 1988, it was extensively examined by paleontologists M. Williams, R. Bakker, and P. J. Currie.  The examination was so extensive that it even included a CAT-scan. They concluded that Nanotyrannus was  not a juvenile Tyrannosaurus rex, but a different species.  Other paleontologists disagree.


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