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DUELING DINOSAURS
V ISITORS TO THE MUSEUM OF
Natural History in ExpositionPark find it difficult not to be
overwhelmed by the sheer size and vibrancy of the "dueling dinosaurs" thatnow grace the main toyer, thanks to agenerous gift from Museum Fellows Dr.S. Jerome and Mrs. Judith D. Tamkin andthe Tamkin Foundation. Towering aboveenthralled onlookers, Tyrannosaurus rexthe best known of all predacious dinosaurs-stoops to attack the rhino-likeTriceratops in the re-creation of a scenethat must have taken place frequently toward the end of the Cretaceous Period,some 65 million years ago. The installation of this new permanent display, whichwill be completed by the end of 1996, isthe last chapter in a story that began somethree decades ago.
Following the removal of the fine artcollections to the Los Angeles CountyMuseum of Art in 1964, Dr. HerbertFriedmann, then director of the NaturalHistory Museum, decreed that the most
pressing priority of his reconstituted institution was to create a new dinosaur halJ.Responding to Dr. Friedmann's challenge,Museum Trustee William T. Sesnon fundeda number of expeditions to Hell Creek inMontana for the purpose oflocating Cretaceous dinosaur material complete enoughto place on exhibition. Ace prospectorHarley Garbani was retained to head thecollecting team, which he staffed mainlywith student volunteers.
Five consecutive collecting seasons inMontana benveen 1964 and 1969 yieldeda wealth of dinosaurian material, includingthree duckbill skeletons (Edmontosa~~rus),
two Tt'iceratops skulls--one associatedwith a partial skeleton, and the skull andfoot of a Tyrannosaul'us. One of theTriceratops skulls was complete, thoughpartially crushed, and has been on permanent exhibit since 1970.
"Vhen discovered, the Tyrannosaurusskull had been disarticulated into manypieces, and it wasn't completely reassembled until 1973. By tllen it had become
obvious that it was the largest and mostcomplete Tyrannosaurus skull known to
science, and it carried this distinction untiljust recently, when an even bigger T rexskull was found by a parry from the BlackHills Institute of SOUtll Dakota.
The Tyrannosaurus skull and footwere associated with additional limb bonefragments and vertebrae, some of whichbelonged to a second, smaller individual.The skull and foot were duly placed ondisplay bur with long·standing regret thatwe had nothing to fill the interveningspace l Then, in the mid 1980s, we exchanged a cast of our skull for the cast ofa headless T rex skeleton that had beenfound by the Tyrrell Museum in Canada.In this way, both institutions acquired thematerial for a relatively complete (if partially fabricated) exhibit. The relocation ofthe Natural History Museum's Jurassicdinosaur skeletons from the main toyer tothe Governors' Gallery in 1992 finally released a large enough space in which to
display Tyra,mosaul'us to good effect.
2 TERRA vO 33 NO.5. SEPTEMBER IOCTOBER 199&
LEFT
Tyrannosaurus rex bones being excavated from an
ancient stream channel near Hell Creek,
Montana, in 1969; a jaw fragment is visible at the
left. Photograph by Walter Frisbee.
BoTTOM, PAGES 2 AND 3
At the end of the 1969 field season, plaster
jackets containing dinosaur bones were loaded
onto pallets for transportation back to los
Angeles. Photograph by Walter Frisbee.
COlfER
The Tamkin Dueling Dinosaurs, Tyrannosaurus rex
and Triceratops, now on display in the main foyer
of the Exposition Park museum. Photograph by
Dick Meier and Dan Watson.
T ERR A VOL. 3] NO • SEPTEMBER / OCTOBER 1996 3
The idea of having the Tyrannosaurus:tIld Triceratops posed in interaction wasthe inspiration of Natural History Museum Modelmaker Michael Stokes, whoprepared a model of his concept for consideration by Museum President and Director James L. Powell. Dr. Powell in turnshowed the model to Dr. and Mrs.Tamkin: excited by the opportunity toprovide the museum with a distinctive hallmark that would be particularly appreciated by our younger visitors, the Tamkinsoffered to underwrite its construction.
The armature or supporting framework for a skeletal mount can be eitherexternal or internal. A classic example ofexternal armature can be seen on themuseum's cast of the long-necked Chinesesauropod Mamenchisaurus(now on display in the Governors' Gallery). Here theneck, legs, and torso are held together byexternal metal bands, and the whole skeleton is supportcd upon three very visiblevertical steel rods.
The Natural History Museum helpedpioneer internal armature, where the skel-
eton is supported 011. a framework that liesinside the bones. This type of mount,which has been used on most of our otherdinosaur and fossil mammal skeletons,provides for a much more realist.ic poscbut has the disadvantage of necessitatingdrilling through and hence destroyingpart of the bone in the process. Evenwhen the mounting technique does notharm the skeletal components, paleon- .tologists are often unhappy at the prospect of putting real fossil bones inmounted skeletons because it is then difficult to study them. However, a compromise was reached when assembling theDueling Dinosaurs.
We decided not to use the real Tyrannosaurus and Triceratops skulls in themount-in part because we wanted themavailable for further scientific study anddidn't want t.hem drilled or otherwisedamaged, but mainly because they arevery heavy, each weighing almost a hundred kilograms (several hundred pounds).Clearly we did not want the skulls breaking off from the relatively slender and
fragile necks in the event of a moderate tosevere carthquake temblor l
Although they were replaced by castsin t.he completed mounts, the real skullswill be located in nearby display caseswhen the installation is complete so thatvisitors may study them close up. Tocomplete the mounts, we incorporated asmany real bones and bone fragments aspossible: about 60 percent of the Triceratops is real bone, and about 15 percentof the TyrannosauntS. (The finishing ofthe casts is so realistic that it is difficult totell from a distance which element is realbone and which is cast.)
The Dueling Dinosaurs were assembled to our design by Research Casting International of Toronto, under thedirection of Peter May, formerly of theRoyal Ontario Museum. May's skilledteam has mounted more than 300 fossilskeletons for museums throughout theworld. Although Research Casting's experts are no strangers to Tricu'atops orTyrannosaurus skeleton mounts, this wastheir first interactive mount of the twospecies. As far as they can tell, this is theonly such mount in the world, and it iscertainly one of which they are extremelyproud-they rank it among their finest efforts to date.
The skeletons were mounted in modules in Canada-the T rex divided intoseven units, the Triceratops into six-andthen shipped to Los Angeles for reassembly on site. The hip units of both animalswere so large that we had to remove thedoors at the museum's north ent.rance toget them into the building. We startedunloading the shipment at 8 a.m. onTuesday, April 2; in less than 24 hours,the two huge skeletons, each weighing680 kilograms (1,500 pounds) were upand in place.
The display was, however, far fromcomplete. Each skekton sits on a solidsteel base plate weighing 450 kilograms(1,000 pounds), and these needed to bewelded together after the fine tuning ofthe combatants' positions and covered bya platform so that the feet of the dino-
4 TERRA VOL )) NO 5 • SEPTEMBER I OCTOBER 1996
saul's will be resting on a flat surfacerather than being suspended above theground.
Finally, the inside walls of the foyerare being ringed with supporting exhibitsabout the people who made the conceptpossible, the different stages of theproject, and the context in which the dinosaurs lived. Several displays will be devoted to other kinds of Ii fe present onearth at the end of the Cretaceous Periodand on the narural history of the two animals. \Vas T rex a predator or a scavenger> Was the Triceratops frill for display,defense, or temperature regulation?These and other intriguing questions willbe addressed.
As the school year begins, we lookforward to seeing visitors of all ages gazing up at the dueling titans and learningmore about life on earth at the very endof the Age of Dinosaurs.
DR. JOHN M. HARRJS
Chief Curator, Paleontology
Of'POSll'e. TOP
During the 1969 excavations near Hell Creek,
Montana, a block of river channel sandstone
matrix containing Tyrannosaurus skull fragments
is encased in plaster to provide reinforcement for
the brittle bones while they are moved from the
field to the Natural History Museum. Photograph
by Walter Frisbee.
AlloY<
Museum Modelmaker Michael Stokes refines his
concept for the Dueling Dinosaurs. Photograph
by Dick Meier.
LEFT
William T. Sesnon (right), Mrs. Sesnon, and then
Curator Reid McDonald examine the plaster
jacket containing a Triceratops skull after it
arrived at the museum at the end of the 1965
Hell Creek field season. Photograph from the
Vertebrate Paleontology archive.
TERRA VOL 33 NO 5 • SEPTEMBER I OCTOBER 19~6 5
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