Category Archives: theropods

The National Fossil Hall Rejects

In April 2014, the paleontology exhibits at the National Museum of Natural History closed for a wall-to-wall renovation. The re-imagined National Fossil Hall will reopen in 2019. We are now approaching the halfway point of this journey, which seems like a fine time to say farewell to some of the more charismatic specimens that are being rotated off display.

In comparison to the old exhibit, the new version will be influenced by a less-is-more design philosophy. While there will not be quite as many individual specimens on display, those that are included will be more visible and will be explored in more detail. This combined with the significant number of new specimens being added means that many old mainstays had to be cut from the roster. Cuts occur for a variety of reasons, including eliminating redundancy, preserving specimens that were not faring well in the open-air exhibit space, and making specimens that have been behind glass for decades available to a new generation of researchers. Retired specimens are of course not going far – they have been relocated to the collections where students and scientists can study them as needed.

Stegomastodon (USNM 10707)

Stegomastodon in 2014. Photo by the author.

The Stegomastodon in 2014. Photo by the author.

The young male Stegomastodon is the largest single specimen that is being retired from the NMNH fossil halls. James Gidley and Kirk Bryan collected this skeleton in the San Pedro Valley of Arizona, during the same 1921 collecting trip that produced the museum’s Glyptotherium (which will be returning). While the genus Stegomastodon was erected in 1912, Gidley referred his specimen to a new species, S. arizonae, due to its more “progressive” physiology and slightly younger age. By 1925, the skeleton was mounted and on display in the Hall of Extinct Monsters. While the original mount used the real fossil tusks, these were eventually replaced with facsimiles.

There are at least two reasons the Stegomastodon will not be returning in 2019. First, there are already two big elephants on display: the mammoth and the mastodon. Elephants take up a lot of space, and a third proboscidean offers diminishing returns when compared to the amount of floor space it requires. More importantly, the Stegomastodon is a holotype specimen, and the exhibit team elected to remove most of these important specimens from the public halls. This is both to keep them safe from the damaging effects of vibration, humidity, and fluctuating temperature, as well as to make them more accessible to researchers.

Paramylodon (USNM V 15164)

Collections staff

Collections staff wheel Paramylodon out of the exhibit hall. Source

During the 1960s, Assistant Curator Clayton Ray oversaw the construction of the short-lived Quaternary Hall, which was reworked into the Hall of Ice Age Mammals. This meant creating a number of brand-new mounts, including several animals from the Rancho La Brea Formation in Los Angeles County. La Brea fossils are not found articulated, but as a jumble of individual elements preserved in asphalt. The Los Angeles Natural History Museum provided NMNH with an assortment of these bones, which preparator Leroy Glenn assembled into two dire wolves, a saber-toothed cat, and the sheep cow-sized sloth Paramylodon.

Paramylodon is another cut for the sake of eliminating redundancy: the two colossal Eremotherium completely overshadow this more-modestly sized sloth. This mount also needed some TLC. For aesthetic reasons, the Paramylodon was given an internal armature, which involves drilling holes through each of the bones. Last year, preparator Alan Zdinak took on the task of disassembling and conserving these damaged fossils with assistance from Michelle Pinsdorf.

Zygorhiza (USNM PAL 537887)

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Zygorhiza cast in the Life in the Ancient Seas gallery. Source

When the Life in the Ancient Seas gallery opened in 1990, it featured a historic Basilosaurus skeleton that had been on display since the 1890s. This ancestral whale was relocated to the Ocean Hall in 2008, and a cast of the smaller whale Zygorhiza took its place in Life in the Ancient Seas. Since there is now an extensive whale evolution exhibit in Ocean Hall, this subject will not be a major part of the new paleontology exhibit. Both Zygorhiza and the dolphin Eurhinodelphis will have to go.

After the old fossil halls closed, Smithsonian affiliate Mark Uhen managed to acquire the retired Zygorhiza mount for George Mason University, where he is a professor. The whale is now on display in the Exploratory Hall atrium, suspended 30 feet in the air.

Tapirs, Horses, and Oreodonts

Photo by the author.

The tapir Hyrachyus and the mini-horse Orohippus. Photo by the author.

The last two major renovations of the NMNH fossil exhibits occurred when mammal specialists were in charge of the Paleobiology Department, and as a result the halls ended up with a lot of Cenozoic mammal mounts (at least 50, by my count). Virtually every major group was covered, often several times over. This menagerie has been culled for the new hall, which will focus on specimens that best tell the story of Earth’s changing climate during the past 66 million years. Casualties include the trio of Hagerman’s horses, the smaller horse Orohippus, the tapirs Hyrachyus and Helaletes, the ruminant Hypertragulus, and the oreodont Merycoidodon. Interestingly, the classic hall’s three large rhinos are sticking around, and will in fact be joined by at least one more.

Brachyceratops (USNM 7953)

Brachyceratops/Rubeosaurus

Brachyceratops/Rubeosaurus. Photo by NMNH Department of Paleobiology.

The pocket-sized ceratopsian historically called Brachyceratops has been on display at NMNH since 1922. Discovered in 1913 by Curator of Fossil Reptiles Charles Gilmore, this animal is one of only a few dinosaur species excavated, prepared, described, and exhibited entirely in-house at NMNH. Assembled by Norman Boss, the mount is actually a composite of five individuals Gilmore found together in northeast Montana.

Gilmore described Brachyceratops as an unusually small but full-grown ceratopsian, but in 1997 Scott Sampson and colleagues confirmed that all five specimens were juveniles. Unfortunately, the fossils lack many diagnostic features that could link them to an adult form. According to Andrew McDonald, the most likely candidate is Rubeosaurus. Nevertheless, without the ability to recognize other growth stages of the same species, the name Brachyceratops is unusable and is generally regarded as a nomen dubium.

It is not difficult to surmise why the Brachyceratops would end up near the bottom of the list of specimens for the new exhibit. It is not especially large or impressive, it doesn’t have a recognizable name (or any proper name at all, really) and it doesn’t tell a critical story about evolution or deep time. With limited space available and new specimens being prepped for display, little Brachyceratops will have to go.

Corythosaurus (USNM V 15493)

Corythosaurus as seen in 1960s

Corythosaurus as seen in the 1960s. Photo courtesy of the Smithsonian Institution Archives.

In 1910, Barnum Brown of the American Museum of Natural History launched the first of several expeditions to the Red Deer River region of Alberta. Seeing Brown’s success and under pressure to prevent the Americans from hauling away so much of their natural heritage, the Canadian Geological Survey assembled their own team of fossil collectors in 1912. This group was headed by independent fossil hunter Charles Sternberg, who was accompanied by his sons George, Levi, and Charles Jr. Having secured several articulated and nearly complete dinosaur skeletons, Brown’s team moved on five years later. The Sternbergs, however, remained at the Red Deer River, and continued to collect specimens for the Royal Ontario Museum.

In 1933, Levi discovered a well-preserved back end of a Corythosaurus, complete with impressions of its pebbly skin. The Smithsonian purchased this specimen in 1937 for use at the Texas Centennial Exposition. It eventually found its way into the permanent paleontology exhibit at NMNH. Unfortunately, the half-Corythosaurus ended up crowded behind more eye-catching displays and was often overlooked by visitors. In the new exhibit, it will have to move aside to make room for new Cretaceous dinosaurs.

Assorted Dinosaur Skulls

Triceratops skull

Original skull of Hatcher the Triceratops, one of many dinosaur skulls coming off exhibit. Photo by the author.

In addition to complete dinosaur mounts, the old NMNH fossil halls included several dinosaur skulls, ranging from the giant cast of the AMNH Tyrannosaurus to the miniscule Bagaceratops. Most of these standalone skulls have been cut, although a few (Diplodocus, Camarasaurus, and Centrosaurus) are sticking around, to say nothing of new specimens being added. Other retirees in this category include the original skulls of Nedoceratops (labeled Diceratops), TriceratopsEdmontosaurus, and Corythosaurus, as well as casts of Protoceratops, Pachycephalosaurus, Stegoceras, Psittacosaurus, and Prenocephalae.

As usual, the reasons these specimens are coming off exhibit are varied. The Nedoceratops skull is a one-of-a-kind holotype that has been the subject of a great deal of conflicting research over its identity and relevance to Maastrichtian ceratopsian diversity. Putting this specimen back in the hands of scientists should help clarify what this bizarre creature actually is. Meanwhile, many of the other skulls (e.g. Protoceratops, Psittacosaurus, and Prenocephalae) come from Asian taxa. In the new fossil hall, the Mesozoic displays will primarily focus on a few well-known ecosystems in North America.

Dolichorynchops (USNM PAL 419645)

Dolichorhynchops from Montana, mounted by Arnie Lewis. Photo by Chip Clark.

Dolichorhynchops in the Life in the Ancient Seas exhibit. Photo by NMNH Department of Paleobiology.

The NMNH Dolichorhynchops is a relatively new mount. It was collected in Montana in 1977 and acquired in a trade with the Denver Museum of Nature and Science. Arnie Lewis prepared it for display in 1987. 24 years later, “Dolly” is being retired to the collections. This is not due to anything wrong with the specimen, but to make way for a bigger, cooler short-necked plesiosaur. NMNH purchased a cast of Rhomaleosaurus from the Henry Ward Natural Science Establishment in the 1890s, but it has not been on exhibit since at least 1910. This cast, which is based on an original at the National Museum of Ireland (and which is identical to the cast at the London Natural History Museum) will make its first public appearance in over a century in the new National Fossil Hall. Sorry, Dolichorhynchops.

This has hardly been a comprehensive list – just a few examples that illustrate the decisions that are made when planning a large-scale exhibit. If you are curious about other favorites from the old halls, you can check on their fate by searching the Department of Paleobiology’s online database. Just go to Search by Field and enter “Deep Time” under Collection Name to see most of the specimens earmarked for the new exhibit.

References

Gidley, J.W. 1925. Fossil Proboscidea and Edentata of the San Pedro Valley, Arizona. Shorter Contributions to General Geology (USGS). Professional Paper 140-B, pp. 83-95.

Gilmore, C.W. 1922. The Smallest Known Horned Dinosaur, BrachyceratopsProceedings of the US National Museum 63:2424.

Gilmore, C.W.  1941. A History of the Division of Vertebrate Paleontology in the United States National Museum. Proceedings of the United States National Museum Vol. 90.

Gilmore, C.W. 1946. Notes on Recently Mounted Reptile Fossil Skeletons in the United States National Museum. Proceedings of the United States National Museum Vol. 96 No. 3196.

McDonald, A.T. 2011. A Subadult Specimen of Rubeosaurus ovatus(Dinosauria: Ceratopsidae), with Observations on other Ceratopsids from the Two Medicine Formation. PLoS ONE 6:8.

Sampson, S.D., Ryan, M.J. and Tanke, D.H. 1997. Craniofacial Ontogeny in Centrosaurine Dinosaurs: Taxonomic and Behavioral Implications. Zoological Journal of the Linnean Society 12:1:293-337.

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Filed under collections, dinosaurs, exhibits, Extinct Monsters, fossil mounts, history of science, mammals, marginocephalians, museums, NMNH, ornithopods, reptiles, theropods

AMNH 5027 at 100

In December 1915, the American Museum of Natural History unveiled the very first mounted Tyrannosaurus rex skeleton, irrevocably cementing the image of the towering reptilian carnivore in the popular psyche. For a generation, AMNH was the only place in the world where one could see T. rex in person. Despite the tyrant king’s fame, old books emphasize the rarity of its fossils. The situation is very different today. In the last 30 years, the number of known Tyrannosaurus specimens has exploded. Once elusive, T. rex is now one of the best known meat-eating dinosaurs, and real and replica skeletons can be seen in museums around the world. The AMNH mount is no longer the only T. rex around, nor is it the biggest or most complete. It was, however, the first, and in a few weeks it will mark the 100th anniversary of its second life. Below is a partially recycled recap of this mount’s extraordinary journey.

Photo by the author.

AMNH 5027 in November 2015. Photo by the author.

The mount known as AMNH 5027 is actually a composite of material from two individuals. The first is the Tyrannosaurus rex holotype (originally AMNH 973, now CM 9380), which was discovered by Barnum Brown and Richard Lull during an AMNH expedition to Montana in 1902. The find consisted of little more than the pelvis, a single femur, one arm and shoulder, and fragmentary portions of the jaw and skull. Nevertheless, this was enough for AMNH director Henry Osborn to publish a brief description in 1905, as well as coin the species’ brilliantly evocative name. That same year, Adam Hermann prepared a plaster replica of the animal’s legs and pelvis, using Allosaurus fossils as reference when sculpting the missing lower legs and feet. This partial mount was initially displayed alongside the skeleton of a large ground bird, in order to accentuate the anatomical similarities.

Brown located a better Tyrannosaurus specimen in 1908. Apparently fearing poaching or scooping, Osborn wrote to Brown that he wished to “keep very quiet about this discovery, because I do not want to see a rush into the country where you are working.” After vanquishing many tons of horrific sandstone overburden, Brown returned to New York with what was at the time the most complete theropod specimen ever found. In addition to an “absolutely perfect” skull, the new find included most of the rib cage and spinal column, including the first half of the tail (Osborn 1916). Lowell Dingus would later describe this second specimen (the true AMNH 5027) as “a nasty old codger”, suffering from severe arthritis and possibly bone cancer. These pathologies were undoubtedly painful and probably debilitating.

Model of unrealized T. rex showdown mount from Osborn 1913.

Model of the unrealized T. rex showdown mount from Osborn 1913.

Osborn initially wanted to mount both Tyrannosaurus specimens facing off over a dead hadrosaur. He even commissioned E.S. Christman to sculpt wooden models which which to plan the scene (shown above). However, the structural limitations inherent to securing heavy fossils to a steel armature, as well as the inadequate amount of Tyrannosaurus fossils available, made such a sensational display impossible to achieve. Instead, the available fossils complemented one another remarkably well in the construction of a single mounted skeleton. Osborn noted this good fortune in 1916, but his statement that the two specimens were “exactly the same size” wasn’t quite accurate. The holotype is actually slightly larger and more robust than the 1908 specimen, and to this day the AMNH Tyrannosaurus mount has oversized legs.

The original Tyrannosaurus rex mount at the American Museum of Natural History. Photo from Dingus 1996.

The original Tyrannosaurus rex mount at AMNH. Note the original 1905 replica legs in the background. Photo from Dingus 1996.

Instead, Hermann’s team prepared a single Tyrannosaurus mount, combining the 1908 specimen with the reconstructed pelvis and legs based on the 1905 holotype. When the completed mount was unveiled in 1915, the media briefly lost their minds. In contemporary newspapers, the skeleton was called “the head of animal creation”, “the prize fighter of antiquity”, and “the absolute warlord of the earth”, among similarly hyperbolic proclamations. Even Osborn got in on the game, calling Tyrannosaurus “the most superb carnivorous mechanism among the terrestrial Vertebrata, in which raptorial destructive power and speed are combined.” With its tooth-laden jaws agape and a long, dragging lizard tail extending its length to over 40 feet, the Tyrannosaurus was akin to a mythical dragon, an impossible monster from a primordial world. This dragon, however, was real, albeit safely dead for 66 million years.

Image courtesy of the AMNH Archives.

T. rex in the Cretaceous Hall, 1960. Image courtesy of the AMNH Research Library.

The AMNH’s claim to the world’s only mounted Tyrannosaurus skeleton ended in 1941, when the holotype was sold to the Carnegie Museum of Natural History. The Pittsburgh museum’s hunch-backed reconstruction of the tyrant king was on display within a year. Although no longer the only T. rex on display, the AMNH mount certainly remained the most viewed as the 20th century progressed. It became an immutable symbol for the institution, visited again and again by generations of museum goers. Its likeness was even used as the iconic cover art of Michael Crichton’s Jurassic Park.

By the 1980s, however, a new wave of dinosaur research had conclusively demonstrated that these animals had been active and socially sophisticated. The AMNH fossil galleries had not been updated since the 1960s, and the upright, tail-dragging T. rex in particular was painfully outdated. AMNH had once been the center of American paleontology, but now its displays were lagging far behind newer museums.

finished mount, room under construction

Restoration of AMNH 5027 was completed nearly three years before the hall reopened. Photo from Dingus 1996.

Between 1987 and 1995, Lowell Dingus coordinated a comprehensive, $44 million renovation of the AMNH fossil exhibits. As part of the project, chief preparator Jeanne Kelly led the restoration and remounting of the most iconic specimens, Apatosaurus and Tyrannosaurus. Of the two mounts, the Tyrannosaurus presented the bigger challenge. The fossils were especially fragile, and some elements, specifically the cervical vertebrae, had never been completely freed from the sandstone matrix. It took six people working for two months just to strip away the layers of shellac applied by the original preparators. All told, the team spent a year and a half dismantling, conserving, and rebuilding the T. rex.

Phil Fraley’s exhibit company constructed the new armature, which gave the tyrant king a more accurate horizontal posture. While the original mount was supported by obtrusive rods extending from the floor, the new version is actually suspended from the ceiling by a pair of barely-visible steel cables. Playing with Christman’s original wooden models, curators Gene Gaffney and Mark Norrell settled on a fairly conservative stalking pose, imbuing the mount with a level of dignity befitting this historic specimen. The restored AMNH 5027 was completed in 1992, but would not be unveiled to the public until the rest of the gallery was finished in 1995. Since that time, tens of millions of visitors have flocked to see this new interpretation of Tyrannosaurus. This is the skeleton that showed the world that dragons are real, and it is still holding court today.

References

Dingus, L. 1996. Next of Kin: Great Fossils at the American Museum of Natural History. New York, NY: Rizzoli International Publications, Inc.

Glut, D.F. 2008. Tyrannosaurus rex: A Century of Celebrity. Tyrannosaurus rex, The Tyrant King. Larson, Peter and Carpenter, Kenneth, eds. Bloomington, IN: Indiana University Press.

McGinnis, H.J. 1982. Carnegie’s Dinosaurs: A Comprehensive Guide to Dinosaur Hall at Carnegie Museum of Natural History, Carnegie Institute. Pittsburgh, PA: The Board of Trustees, Carnegie Institute.

Norell, M, Gaffney, E, and Dingus, L. 1995. Discovering Dinosaurs in the American Museum of Natural History. New York, NY: Alfred A. Knopf, Inc.

Osborn, H.F. 1906. Tyrannosaurus, Upper Cretaceous Carnivorous Dinosaur: Second Communication. Bulletin of the American Museum of Natural History vol. 22, pp. 281-296.

Osborn, H.F. 1913. Tyrannosaurus, Restoration and Model of the Skeleton. Bulletin of the American Museum of Natural History vol 32, pp. 9-12.

Osborn, H.F. 1916. Skeletal Adaptations of Ornitholestes, Struthiomimus, and TyrannosaurusBulletin of the American Museum of Natural History vol 35, pp. 733-771.

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Filed under AMNH, dinosaurs, fossil mounts, history of science, museums, theropods

The Nation’s T. rex Revealed

The Nation's T. rex was temporarily assembled in the RCI workshop for inspection by Smithsonian staff. Source

The Nation’s T. rex was temporarily assembled in the RCI workshop for inspection by Smithsonian staff. Source

Yesterday, a press embargo lifted and the world got it’s first look at the pose the Nation’s T. rex will assume in the new fossil hall at the National Museum of Natural History. I don’t have much to add to the solid coverage at The Washington Post, NPR, and Smithsonian Magazine except holy crap, that’s awesome.

The photo above (by Nikki Kahn of The Washington Post) was taken when Smithsonian staff visited the Research Casting International workshop to inspect the mount’s progress. Located outside of Toronto, RCI is the industry leader in the art of creating mounted fossil skeletons, and their work is on display in museums all over the world. The Nation’s T. rex is one of 52 mounts the company will create for NMNH over the next three years.

Dr. Carrano gestures toward the awesomeness behind him.

Dr. Carrano gestures toward the awesomeness behind him. Source

The Nation’s T. rex (also known as Wankel Rex) is new to NMNH, but it is not a new specimen. It was discovered by Montana rancher Kathy Wankel in 1988 on land owned by the Army Corps of Engineers. The skeleton, which was for a time the most complete Tyrannosaurus known, was held in trust at the Museum of the Rockies until last April, when the Corps loaned the specimen to the Smithsonian for the next 50 years. This is the first time the original fossils have been displayed in a standing mount, but RCI has been producing casts of the specimen for years. Examples can be seen at the Great North Museum, the Royal Ontario Museum, the Perot Museum of Nature and Science, and even the Google Campus.

The Smithsonian team inspecting every inch of the 2,000 pound mount included Curator of Dinosauria Matt Carrano, Exhibit Project Manager Siobhan Starrs, and Preparator Steve Jabo. The violent scene, with the Tyrannosaurus preparing to decapitate its Triceratops prey, was first suggested by Carrano over two years ago. The inspiration came from research by Denver Fowler and colleagues, which proposed that Tyrannosaurus regularly dismembered Triceratops by pulling the head off by the frill. The dynamic pose sets the Nation’s T. rex apart from the more “regal” stances other museums have chosen for their Tyrannosaurus mounts, and also reminds visitors that this animal was a living, acting being within its environment.

A 3-D printed model of the skeleton was used to plan the pose. Source

The exhibit team used a 3-D printed model of the skeleton to plan the pose. Source

The tyrant king’s prey is none other than a cast of Hatcher, NMNH’s resident Triceratops. This composite skeleton was the first mounted Triceratops ever exhibited, and it has been on display in one form or another since 1905. An updated reproduction of Hatcher can be seen right now in The Last American Dinosaurs, but apparently this will be its last hurrah. As Carrano put it, “Hatcher’s done its duty.” Even relegated to the role of food, however, Hatcher is still an impressive beast. The skeleton is nearly as long as the Nation’s T. rex, and noticeably bigger than the Triceratops mounts at other major U.S. museums.

Hatcher Photo by the author.

Poor Hatcher knows nothing of his imminent demise at the claws of a 38-foot murderbird. Photo by the author.

The NMNH team had a few notes for RCI, both for the sake of accuracy and the sake of the exhibit. Carrano requested that the fibula be rotated slightly, while Starrs emphasized that the tail should be at least 10 feet off the ground, to prevent over-enthusiastic visitors from grabbing at it. The workshop visit was also an opportunity to explore how the mount would look among the other denizens of the National Fossil Hall. Hatcher and the Nation’s T. rex will be sharing space on the Creataceous platform with Edmontosaurus, Thescelosaurus, and the crocodile relative Champsosaurus, among others. Working out dynamic poses that also keep key lines of sight open is no easy task, and the gallery space needs to be planned down to the inch.

As is now industry standard, RCI’s armature is made up of intricate steel cradles that are custom fitted to hold each of the 150 real fossils in place. Unlike many historic mounts, no holes have been drilled in the bones and none of the delicate fossils are supporting the structure’s weight. Most bones can be removed individually, and with the right equipment, the entire mount can be assembled in just a few hours. As such, we can rest assured that this display will not only be incredibly cool, but the authentic 66 million-year-old fossils will be as safe as they could possibly be while on view for 7 million visitors per year.

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Filed under dinosaurs, exhibits, fossil mounts, marginocephalians, museums, NMNH, theropods

Denver’s Fighting Dinosaurs

Allosaurus and Stegosaurus mount

Allosaurus and Stegosaurus mounts at the Denver Museum of Nature and Science. Source

Just a quick post today to keep the blog moving. The Allosaurus and Stegosaurus skeletons at the Denver Museum of Nature and Science are among my all-time favorite fossil mounts. While there is no shortage of fighting dinosaur displays today, these mounts were something of a novelty when they were unveiled in 1995 as the centerpieces of the trendsetting “Prehistoric Journey” exhibition. A far cry from the stiff, macabre trophies that had dominated paleontology exhibits since the beginning of the 20th century, the Allosaurus and Stegosaurus plainly represent swift and active animals. Unlike many similar scenes, however, the action here is tempered with careful attention to anatomical detail: no limbs are hyperextended, and no bones are out of place.

The Stegosaurus

A postcard showing STegosaurus in the 50s

This postcard shows the original Stegosaurus mount around 1950.

High school teacher Frank Kessler discovered the Stegosaurus (DMNH 1483) in 1937 while leading a nature hike north of Cañon City. While the Garden Park region had been known for its Jurassic dinosaur fossils since the days of O.C. Marsh and E.D. Cope, Kessler’s find was in a previously unexplored area. Kessler contacted the Denver Museum of Natural History (now the DMNS), and Robert Landberg was dispatched to lead a thorough excavation. Landberg eventually recovered a 70% intact Stegosaurus, in addition to a multitude of turtles, crocodiles, and isolated dinosaur bones.

Back in Denver, Phillip Reinheimer assembled the Stegosaurus fossils into a standing mount. A former steelworker from Pittsburgh, Reinheimer was initially hired by the museum to maintain the furnaces, but eventually proved to be an uncommonly talented fossil preparator. Described by Johnson and Stucky as “a master craftsman,” Reinheimer remains something of a legend among preparators to this day. Reinheimer completed the Stegosaurus mount in 1938, and it remained a focal point of the museum’s fossil exhibits for decades afterward. In 1982, this specific specimen was named the state fossil of Colorado.

The Allosaurus

A close up of Allosaurus

Another look at Allosaurus and Stegosaurus. Source

In 1979, 13 year-old India Wood discovered and identified an Allosaurus skeleton on her family’s ranch in Moffat County, Colorado. She excavated the find herself over a period of three years, until her mother encouraged her to reach out to the DMNS. After seeing the fossils Wood had been collecting in a box under her bed, paleontology curator K. Don Lindsay agreed to excavate the rest of the skeleton.

The project took two more summers to complete, and Wood remained an active participant. Although many at the museum remember being impressed by her knowledge and talent, Wood ultimately did not pursue paleontology as a career – she instead went on to earn an MBA from MIT and founded a business consulting firm. Meanwhile, Wood’s Allosaurus (DMNH 2149) remained in storage for more than a decade – until it was selected to feature in an ambitious new exhibit.

Prehistoric Journey

From left to right

From left to right: Wood’s Allosaurus, Karen Alf, Bryan Small, Jon Christians, Jerry Harris, Jennifer Moerman, Ken Carpenter, and Kessler’s Stegosaurus. Image from Johnson and Stucky 2013.

The DMNS had been a powerhouse of paleontology research in the early and mid 20th century, but by the 1980s its reputation had slipped away. That changed in 1989 when Richard Stucky came on board as the new Curator of Vertebrate Paleontology. Stucky brought order to the museum’s historic collections, and laid out plans for a comprehensive new exhibit entitled “Prehistoric Journey.” He also hired a new pool of talent to make the project happen, including paleontologist and preparator Ken Carpenter. As Chief Preparator, Carpenter was tasked with moving, restoring, and in some cases remaking the classic Reinheimer mounts, including the Kessler Stegosaurus. The DMNS crew also ventured into the field to collect new material for Prehistoric Journey. Among the most impressive finds was a new Stegosaurus (DMNH 2818), discovered by Bryan Small at Garden Park only a few hundred yards from where the Kessler specimen was unearthed. This articulated specimen clarified for the first time the position of the animal’s plates and spikes, and also confirmed that Stegosaurus had throat armor made up of tiny hexagonal ossicles. All of this informed the remounting of the Kessler Stegosaurus.

Carpenter’s take on this classic specimen paired it with India Wood’s Allosaurus, right in the middle of the Prehistoric Journey dinosaur gallery. The Stegosaurus is shown defending two (largely reconstructed) juveniles from the attacking theropod, while five or six Othnielia (casts) flee the scene. Twenty years after its 1995 debut, this scene is still among the most impressive fossil mounts around because of the seemingly effortless way it captures action and behavior. Carpenter and his colleagues did not only restore the shape of these animals but breathed life into them. The viewer cannot help but imagine the events that preceded this encounter, as well as the eventual outcome. The suspended bones are like brush strokes in an impressionist painting, swooping through the space and imbuing it with energy and motion. The fact that these are mostly original fossils rather than lightweight casts makes the display all the more impressive. I’ve said it many times before, but it bears repeating that fossil mounts are fascinating, challenging objects in that they are both authentic specimens and interpretive creations. In many cases these conflicting identities are jarring. However, with the right amounts of artistry, aptitude, and solid science, a fossil mount can transcend this juxtaposition and serve each identity equally well. Not an easy feat, but the DMNS Stegosaurus and Allosaurus are a defining example of the craft.

References

Carpenter, K. (1998). Armor of Stegosaurus stenops and the Taphonomic History of a New Specimen from Garden Park, Colorado. Modern Geology Vol. 22: pp. 127-144.

Johnson, K.R. and Stucky, R.K. (1995). Prehistoric Journey: A History of Life on Earth. Golden, CO: Fulcrum Publishing.

Johnson, K.R. and Stucky, R.K. (2013). Paleontology: Discovering the Ancient History of the American West. Denver Museum of Nature and Science Annals No. 4: pp. 231-282..

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Filed under dinosaurs, DMNS, fossil mounts, museums, theropods, thyreophorans

A Trio of Tyrants

The frentic search for North American dinosaur fossils in the late 19th and early 20th centuries can be divided into three phases. First came O.C. Marsh and E.D Cope, whose infamous rivalry resulted in literal trainloads of fossil material and laid the groundwork for our present understanding of dinosaur diversity. Next, teams sponsored by the newly-formed American, Carnegie, and Field museums returned to the same hunting grounds in the western interior to secure display-worthy specimens for their great halls of exhibition. The final phase was smaller in scale but yielded dinosaur specimens so spectacularly complete that most have gone unmatched to this day.

This third fossil rush occurred not in the United States but in Canada, along the cliff-like banks of Alberta’s Red Deer River. Fossil hunting in this region was pioneered in the late 1800s by George Dawson, Joseph Tyrell, and Lawrence Lambe, all working for the Canadian Geological Survey. This success did not go unnoticed by the the American Museum of Natural History’s Department of Vertebrate Paleontology. In 1910, the museum mounted an expedition led by Barnum Brown to the Red Deer River. Rather ingeniously, Brown’s team acquired a pair of 30-foot floating barges, which were used as mobile platforms from which they could excavate the steep river banks. The barges also served as floating campsites and a handy means of transportation in a region without reliable roads.The adventurous Brown was already a media favorite, and the publicity surrounding his Alberta expeditions only increased when the team started bringing back fully articulated and nearly complete dinosaur skeletons (including several with skin impressions).

Under pressure from constituents concerned that the Americans were hauling away so much of their natural heritage, the Canadian government formed its own team of fossil collectors in 1912. The new Canadian Geological Survey team was headed by independent fossil hunter Charles H. Sternberg (a veteran collector who had once worked for Cope) and his sons George, Levi, and Charles Jr. The Canadian and American teams worked in the same region for the next five field seasons. Their rivalry was usually good-natured, but on more than one occasion Brown saw fit to grumble about the Sternbergs’ ethics (never mind that he was the one permanently removing fossils from their country of origin).

Gorgosaurus at AMNH

Three tyrannosaurs mounted in relief at AMNH. Image courtesy of the AMNH Research Library.

All of this is so much preamble for the actual topic of this post – three remarkable Gorgosaurus skeletons* collected near the Red Deer River during the Canadian fossil rush. All three were eventually mounted in relief by AMNH preparator Peter Kaisen, and for a time they were displayed together in the Hall of Fossil Reptiles. These specimens are on the short list of most complete large theropod dinosaurs ever discovered, and in their day they provided researchers an unprecedented look at the physiology of these amazing animals. Nearly a century later, the three mounts are virtually unchanged. Locked behind glass for decades and largely inaccessible to researchers, the mounts themselves are now relics of a fascinating transitional period in the history of dinosaur studies.

*AMNH also recovered a fourth tyrannosaur during this period – Gorgeous George the Daspletosaurus.

As usual, a brief explanation of nomenclature is required. William Matthew and Barnum Brown originally described these specimens as Gorgosaurus, a genus that Dale Russell sank into Albertosaurus in 1970. Most specialists no longer support this synonymization, but the specimens at AMNH are still labeled as Albertosaurus.

Gorgosaurus libratus – USNM 12814

gorgo

A recent photo of USNM 12812 from the ongoing renovation of the national fossil hall. Source

USNM 12814 (originally designated AMNH 5248) was excavated by Brown’s company in 1913 and prepared for display in 1918. Kaisen elected to recreate the death pose in which the Gorgosaurus was found, with its head swept backward over its body. All told, the finished mount included a skull, a complete set of cervical and dorsal vertebrae, complete forelimbs, and a single femur – the pelvis and the rest of the hindlimbs were filled in with casts from other specimens. Since the skeleton was mounted in relief, Kaisen simply painted the tail onto the backdrop.

After at least a dozen years on display at AMNH, the Gorgosaurus was traded to the National Museum of Natural History as part of a complicated deal between the two museums. While surveying fossil collections throughout the United States, Brown realized that a single Barosaurus skeleton from Dinosaur National Monument had been divided among three different institutions. NMNH had the neck and part of one forelimb, the Carnegie Museum had the tail, and the University of Utah had the rest. Between 1929 and 1933, Brown arranged a series of trades in order to unify the Barosaurus at AMNH. The Smithsonian in particular drove a hard bargain – the museum had already invested $3400 in preparing their Barosaurus section, and paleontology staff wanted a good return for their investment. Brown’s initial offer was the fully prepared and mounted Gorgosaurus. Although AMNH valued the field and prep time spent on the fossils at $4573, it was at that point a duplicate specimen taking up valuable space in their increasingly crowded exhibit hall.

NMNH dinosaur specialist Charles Gilmore confided in Brown that he was okay with this trade, but fellow Smithsonian paleontologist Alexander Wetmore wasn’t sold. For years, NMNH staff had been trying to acquire one of the many Moropus specimens AMNH had collected at the Agate Fossil Beds in Nebraska. NMNH had offered a variety of specimens to trade, even sending AMNH a set of brontothere skulls at one point, but AMNH was adamant the Moropus fossils could only be exchanged for cash. Brown really wanted that Barosaurus neck, so in January of 1933, he finally relented and offered the Smithsonian a largely complete Moropus in addition to the Gorgosaurus. Not long after, the Gorgosaurus relief mount found its way into the Hall of Extinct Monsters at NMNH.

Gorgosaurus sp. – AMNH 5458

albertosaurus

A technician (probably Kaisen) adjusts the steel strap holding the femur in place. Source

Brown’s team found their second Gorgosaurus near Steveville, Alberta in 1914. Complete save for the left leg, right arm, and parts of the rib cage and tail, the mount was ready for display in May of 1921. At 24 feet long and 14 feet high, this was by far the largest relief mount at the museum. In fact, it was too big to fit through the workshop doorway in one piece, so Kaisen constructed it in eight sections that were sealed together in the exhibit hall. Each section had its own wooden frame for support, and the bones themselves were held in place with steel straps. The skull, jaw, and left forearm could be removed for individual study. This was unusual for the period (most contemporary fossil mounts were designed to be permanent) and speaks volumes about this specimen’s unique scientific value.

This mount is particularly notable for its awkward running pose. Directly contradicting many narratives of early 20th century paleontology, Matthew and Brown envisioned Gorgosaurus as an animal that “walked and ran much like a gigantic bird.” The AMNH team posed this mount after studying photos of bipedally running lizards, particularly the western tiger lizard*. However, Matthew and Brown noted that the dinosaur’s  limb proportions and range of motion more closely resemble a bird than a lizard, and adjusted the pose accordingly. They also advised a more conservative stride length to compensate for the animal’s considerable weight.

*Matthew and Brown do not provide a scientific name, and the common name “western tiger lizard” doesn’t seem to be used any more. Anyone know what it’s called today?

The final pose was a compromise between the elevated torso of a running lizard and the comparatively tight gait of a bird. It looks more than a little strange, but AMNH 5458 is certainly closer to our present understanding of theropod posture than most mounts of the era. Matthew and Brown’s interpretation of Gorgosaurus turned out to be ahead of its time. Some contemporary researchers, including Lawrence Lambe, declared the running pose to be highly improbable, and virtually all theropod mounts constructed over the next 60 years returned to the tail-dragging posture of the 1915 AMNH Tyrannosaurus.

Gorgosaurus sternbergi” – AMNH 5664

gorgo sternbergi

Gorgosaurus “sternbergi” as it was discovered and originally mounted. Source

The most complete tyrannosaur from the Red Deer River was not collected by the AMNH party, but by the Sternbergs. The elder Charles Sternberg discovered the specimen in 1917, entirely intact save for the left arm and the very end of the tail. In fact, this was the most complete large theropod ever found in North America until it was surpassed by yet another Gorgosaurus, TCM 2001.89.1. Sternberg first attempted to sell the specimen to the British Museum. They weren’t interested, but AMNH was. In 1918, the Department of Vertebrate Paleontology bought the skeleton for $2000, thus completing the tyrannosaur trio.

Matthew and Brown described AMNH 5664 as a new species – Gorgosaurus sternbergi. In their 1921 publication, they describe the skull as longer and shallower than other Gorgosaurus specimens, with rounder orbits. However, Brown and Matthew recognized that these could be juvenile characteristics, noting as well that the unfused pelvic bones were an indication of immaturity. As early as 1970, this specimen was suspected to be a juvenile Gorgosaurus (or Albertosaurus) libratus.

Kaisen prepared the relief mount in 1921, this time assisted by Carl Sorenson. The photo above shows the original version of this mount, with the tail projecting straight back from the body. This was how Sternberg discovered the skeleton, and Kaisen wanted to keep the death pose intact. In the 1950s, the tail was “corrected” to make it drag on the ground. Although the display has not been altered since, the revised tail posture is now considered inaccurate. Indeed, the vertebrae apparently had to be angled unnaturally to make the dragging tail work at all.

AMNH 5027 was restored and remounted in 1995.

The Gorgosaurus plaque mounts hide behind Tyrannosaurus rex at AMNH. Photo by the author.

All three Gorgosaurus specimens were first displayed in the cramped quarters of the Hall of Fossil Reptiles (now the Hall of Primitive Mammals) with the rest of the growing AMNH dinosaur collection (USNM 12814 and the tail of AMNH 5664 are barely visible in this photo). 5458 and 5664 moved to the newly opened Great Hall of Dinosaurs in 1922. They flanked the gallery’s rear doorway for 70 years before being moved to the Hall of Saurischian Dinosaurs in 1994. Meanwhile, the Gorgosaurus transferred to the Smithsonian first appeared in the Hall of Extinct Monsters in the 1940s, displayed behind glass on the north wall. It switched to the south side in 1962, and moved about 30 feet up the wall in 1981, where it could only be properly seen from the mezzanine ramp.

Aside from the aforementioned alternation to AMNH 5664’s tail, the Red Deer River Gorgosaurus trio has not been modified since they were first built. This may well change in the not-to-distant future. The NMNH crew is hard at work on a thorough renovation of the national fossil hall, dismantling and restoring all of the classic dinosaur mounts. Meanwhile, the current AMNH paleontology exhibits are now 20 years old, and will soon be due for a similar overhaul. Both institutions will need to decide whether or not to free the Gorgosaurus specimens from their plaster substrate. This would be an extremely difficult process, but not impossible – Phil Fraley Productions recently rebuilt the Carnegie Museum’s Corythosaurus, Dryosaurus, and Camptosaurus as free-standing mounts. Dismantling the relief mounts would give a new generation of scientists access to these important specimens, and it would allow for the skeletons to be given more accurate poses. In addition, a standing Gorgosaurus mount alongside either museum’s Tyrannosaurus rex would be both informative and awesome.

Nevertheless, remaking these mounts would also destroy significant historical context. The carefully restored death pose of USNM 12812 seems like something worth preserving, and the AMNH specimens represent an important transitional period in the history of dinosaur science. In the past, museums have often taken a “science marches on” approach when updating aging displays, but in these mounts might be unique enough in their current form to be left as-is. What do you think?

References

Carr, T.D. (1999). Craniofacial Ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology 19: 497-520.

Colbert, E.H. (1968). Men and Dinosaurs: The Search in Field and Laboratory. New York, NY: E.P. Dutton & Co., Inc.

Gilmore, C.W. (1946). Notes on Recently Mounted Reptile Fossil Skeletons in the United States National Museum. Proceedings of the United States National Museum Vol. 96 No. 3196.

The Long Road to a Fossil Swap. Digging the Fossil Record, March 19, 2015. http://nmnh.typepad.com/smithsonian_fossils/2015/03/gorgosaurus-and-moropus.html

Matthew, W.D. and Brown, B. (1923). Preliminary Notices of Skeletons and Skulls of Deinodontidae from the Cretaceous of Alberta. American Museum Noviates 89: 1-10.

Russell, D. (1970). Tyrannosaurs from the Late Cretaceous of western Canada. National Museum of Natural Science Publications in Palaeontology 1: 1–34.

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Filed under AMNH, dinosaurs, field work, fossil mounts, history of science, museums, NMNH, reptiles, theropods

Extinct Monsters: The Marsh Dinosaurs, Part III

allosaurus

A close-up of Allosaurus. Photo by the author.

Click here to start the NMNH series from the beginning.

Some time ago, I wrote about the O.C. Marsh dinosaurs at the National Museum of Natural History. These are the mounted skeletons made from the enormous collection of fossils Marsh accumulated while working for the United States Geological Survey – if you’d like, you can catch up with Part 1 (on Edmontosaurus and Triceratops) and Part 2 (on Camptosaurus, Ceratosaurus, and Stegosaurus). Looking back, I noticed that I never actually finished, so here are the two Marsh dinosaurs with as-yet untold stories.

The Thescelosaurus

The name Thescelosaurus neglectus means “neglected wonderful lizard”, because Smithsonian paleontologist Charles Gilmore found the original specimen at the bottom of a crate, more than 10 years after it arrived at NMNH. Still buried its its field jacket, this skeleton had been long overlooked by both Marsh and the museum staff. Nevertheless, Gilmore found that it was remarkably complete and that it represented a taxon new to science.

Gilmore's illustration

An illustration of the Thescelosaurus holotype prior to reconstruction. Source

Thescelosaurus at USNM.

Thescelosaurus as displayed after 1981. Photo by Chip Clark.

The specimen that would become the Thescelosaurus holotype (USNM 7757) was excavated by John Bell Hatcher and William Utterback in July of 1891, while they were collecting for Marsh in Niobrara County, Wyoming. 20 years later, Gilmore discovered that the skeleton was articulated and intact, save for the head, neck, and parts of the shoulder. He even found small patches of preserved skin on the tail and legs. According to Gilmore, the animal had been buried rapidly after death, since it showed no signs of dismemberment by scavengers.

After describing the fossils, Gilmore mounted the Thesclosaurus in relief on its left side. Other than the reconstructed skull (modeled after Hypsilophodon), the specimen was displayed almost exactly as it was found. This was important to Gilmore, because as he wrote in his published description, “I am…of the opinion that specimens so exhibited hold the attention of the average museum visitor far longer and arouse a keener interest in the genuineness of the specimen than does a skeleton that has been freed from the rock and mounted in an upright, lifelike posture.” Today at least, I suspect that the opposite is true –  visitors are generally more impressed by dynamic standing mounts than by reliefs that preserve death poses. Still, it’s fascinating to gain a small amount of insight into the motivations of a pioneering mount-maker.

Although it was first displayed in the Hall of Extinct Monsters, the Thescelosaurus was most prominently exhibited in the 1963 version of the NMNH fossil halls. Here, it joined the Edmontosaurus, Gorgosaurus, and partial Corythosaurus relief mounts along the south wall. In life, these animals were vastly removed from one another in time and space, but displayed together they almost appeared to be parts of a single quarry face. The Thescelosaurus moved to the north wall in 1981, unfortunately placed rather high and out of most visitors’ line of sight.

thescrci

Thescelosaurus cast in the RCI workshop. Source

thescrci2

Close-up of the new Thescelosaurus skull. Source

When the new National Fossil Hall opens in 2019, USNM 7757 will be replaced with a duplicate cast. The original bones will be moved to the collections, where they can be properly studied for the first time in a century. Already, technicians at Research Casting International have freed the skeleton’s left side, which had never been fully prepared. The exhibit replica assembled by RCI is beautiful, retaining the ossified tendons and cartilage impressions of the original. Mounted in a running pose, the new cast also features an updated head, based on Clint Boyd’s recent description of Thescelosaurus cranial anatomy.

The Allosaurus

Built in 1981, the Allosaurus fragilis (USNM 4734) was the last Marsh Collection dinosaur to be mounted, although bits and pieces have been on display at NMNH since 1920. There has been considerable interest in this individual recently, in part because Kenneth Carpenter and Gregory Paul proposed in 2010 that it become the neotype for Allosaurus – more on that in a moment. Others are interested in this specimen because of its unique pathologies. In addition to several broken and healed bones, the Allosaurus has a massive puncture wound on its left scapula, which nicely matches the diameter of a Stegosaurus tail spike.

Benjamin Mudge collected this specimen in 1877 near Cañon City, Colorado. Known as the Garden Park quarry, this site also produced the Stegosaurus, Camptosaurus, and Ceratosaurus on display at NMNH. Although the Smithsonian obtained the Allosaurus with the rest of the Marsh Collection around 1900, Gilmore did not look at it (or any of the theropod material) until at least 1911. All told, USNM 4734 consists of a partial skull and jaw, a complete set of presacral and sacral vertebrae, a few ribs, a pelvis, and virtually complete arms and legs. It would have had a tail as well, but Mudge’s crew accidentally threw the articulated tail over a cliff while excavating the skeleton. Norman Boss assembled a reconstructed skull, which was displayed through the 1970s. The articulated legs and feet were exhibited in a free-standing case until the late 1950s.

Reconstructed skull

Allosaurus skull  as reconstructed by Norman Boss. Image from Gilmore 1920.

This specimen’s taxonomic history merits some discussion. The holotype Marsh selected when naming Allosaurus (YPM 1930) is notoriously poor, consisting of a single phalanx, two dorsal centra, and a tooth. Dozens of very complete skeletons attributed to Allosaurus are now known, and most specialists basically agree on what an Allosaurus is, but the lack of a usable type with which to define the taxon has been an ongoing problem.

The far more complete USNM 4734 was recovered from the same quarry as the Allosaurus holotype, during the same 1877 field season. Marsh himself actually used this specimen, rather than his designated type, to illustrate subsequent publications on Allosaurus. In 1920, Gilmore flirted with the idea of nominating USNM 4734 as a neotype for Allosaurus, but for reasons that I find difficult to follow, he decided to lump both specimens into the older name Antrodemus valens. Joseph Leidy coined Antrodemus in 1870 based on a single caudal vertebra with no geologic provenance, so this move did little to fix the underlying issue. Nevertheless, Antrodemus remained a popular synonym for Allosaurus in some circles for several decades.

allosaurusskullprep

Arnold Lewis rebuilds the Allosaurus skull in 1979. Image from Thomson 1985.

When the NMNH fossil halls were renovated in 1981, the designers noticed that the exhibit badly needed a large theropod mount. Arnold Lewis was tapped to design and construct a complete mounted version of USNM 4734, with some assistance from Ken Carpenter. The tail was cast from a Brigham Young University specimen, but Lewis sculpted the belly ribs and sternum using an alligator skeleton as reference. The completed Allosaurus measures 17 feet from its grinning jaws to the tip of its tail, and a form-hugging armature makes it look particularly dynamic. This mount has been a favorite among visitors for more than 30 years, although the 2001 addition of a Stan the Tyrannosaurus cast has somewhat overshadowed the smaller theropod.

Allosaurus

The complete Allosaurus skeleton was finally exhibited in 1981. Photo by the author.

Technicians from Research Casting International took down the Allosaurus in the summer of 2014 as part of the current round of renovations. You can watch a video of the de-installation here. The skeleton will be remounted in a few years (crouching beside a nest mound), but Smithsonian researchers want to get a good look at it before that happens. In particular, curator Matt Carrano has been wondering for some time whether a partial jaw Marsh named “Labrosaurus ferox” actually belongs to this specimen. The “Labrosaurus” jaw, which has an unusual pathology caused by a bite or twisting force, came from the same quarry as USNM 4734, and appears to be the same portion of jaw that the more complete skeleton is missing. Time will tell whether Carrano’s hunch is correct. Meanwhile, Carpenter and Paul’s petition to replace the Allosaurus type with this more complete specimen from the same locality is still pending. We should expect to hear more about that soon, as well.

References

Carpenter, K., Madsen, J.H., and Lewis, L. (1994). Mounting of Fossil Vertebrate Skeletons. Vertebrate Paleontological Techniques. 285-322.

Gilmore, C. M. (1915). Osteology of Thescelosaurus, an ornithopodus dinosaur from the Lance Formation of Wyoming. Proceedings of the U.S. National Museum 49:2127:591–616.

Gilmore, C.M. (1920). Osteology of the Carnivorous Dinosauria in the United States National Museum with Special Reference to the Genera Antrodemus (Allosaurus) and CeratosaurusUnited States National Museum Bulletin 110:1-154.

Lee, J.J. (2014). The Smithsonian Disassembles its Dinosaurs. National Geographic Online.  http://news.nationalgeographic.com/news/2014/07/140731-dinosaur-hall-smithsonian-renovation-culture-science/

Paul, G.S. and Carpenter, K. (2010). Allosaurus Marsh, 1877 (Dinosauria, Theropoda): proposed conservation of usage by designation of a neotype for its type species Allosaurus fragilis Marsh, 1877. Bulletin of Zoological Nomenclature 67:1:53-56.

Thomson, P. (1985). Auks, Rocks, and the Odd Dinosaur: Inside Stories from the Smithsonian’s Museum of Natural History. New York, NY: Thomas Y. Crowell.

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Filed under dinosaurs, exhibits, Extinct Monsters, fossil mounts, museums, NMNH, ornithopods, theropods

The Carnegie Quarry Diaspora

About 150 million years ago, a severe drought ravaged the western interior of North America. In eastern Utah, malnourished dinosaurs gathered near a dwindling river. Unwilling or unable to leave the water source, they eventually died of thirst or disease. When rain finally returned to the region, three or four successive flash floods washed dozens of animal carcasses into a relatively small depositional area to the southeast. Today, this site is known as the Carnegie Quarry at Dinosaur National Monument, and it is one of the most incredible fossil sites in the world.

Dinosaur National Monument interns collect data on the quarry wall.

Dinosaur National Monument interns collect data on the quarry wall. Source

Today, a structure encompassing a 180-foot section of the deposit (less than half its total length) allows visitors to view nearly 1400 dinosaur bones in situ. However, the fossils on display at Dinosaur National Monument represent only a portion of the material found at the Carnegie Quarry. Between the site’s discovery in 1908 and the establishment of the quarry wall exhibit, more than 20 reasonably complete dinosaur skeletons and dozens more incomplete specimens were excavated and distributed to museums in the US and Canada. No less than eleven mounted skeletons have been created from this material, and they are all still on display today. Although they are thousands of miles from their place of discovery and exhibited in four different cities, these mounts all represent individuals that lived and died in the same environment. They may have even encountered each other in life!

The Discovery

Earl Douglass was already an established fossil hunter when the Carnegie Museum of Natural History hired him in 1902. Late in the 1909 field season, Douglass was prospecting near the confluence of the Green and Yampa Rivers when he spotted a series of sauropod vertebrae eroding out of the rocks. Once Douglass and his crew began excavating the fossils, it became apparent that they had not just one remarkably complete dinosaur, but several. Douglass called it a “beautiful sight,” and CMNH director William Holland could barely contain his glee in his reports back to the Pittsburgh museum. Under Douglass’s management, CMNH crews worked at what became known as the Carnegie Quarry for 13 years. The dinosaur fossils were jumbled and often overlaid one another, so the excavators had to work on multiple skeletons simultaneously. The especially hard sandstone also slowed their work, and the team regularly resorted to huge horse-drawn plows and even dynamite to reach the fossils. Eventually railway tracks were installed to help transport blocks of sandstone out of the quarry.

In 1915, Holland successfully petitioned Woodrow Wilson to preserve the site as a national monument. CMNH crews continued to excavate until early 1923. At that point, their primary benefactor Andrew Carnegie had died, and funding for field work was dwindling. Other museums collected from the quarry periodically in the years that followed, but Douglass’s idea to contain the remaining fossils in an on-site museum was not realized until 1958.

The Mounts

CMNH

CMNH Apatosaurus. Historic photo from McGinnis 1982; modern photo source.

Apatosaurus louisae – CM 3018

The CMNH Apatosaurus was the first dinosaur discovered at the Carnegie Quarry. After Douglass first spotted the articulated caudal vertebrae in August of 1909, his crew spent several months extracting the rest of the skeleton from the rocks. The excavation continued into early 1910, and by the time they were finished they had the most complete Apatosaurus ever found – a title the specimen holds to this day. Holland mounted the 77-foot skeleton alongside the museum’s Diplodocus in just three years, at the time a record for a sauropod mount.

Holland famously left his Apatosaurus headless for decades due to a disagreement with Henry Osborn of the American Museum of Natural History. Douglass recovered a skull that almost certainly belonged to the Apatosaurus, but Holland opted not to use it because it contradicted the sculpted head already in place on the AMNH Apatosaurus mount. After Holland’s death in 1932, museum staff quietly added a casted Camarasaurus skull as a placeholder. This was finally replaced with a proper Apatosaurus skull in 1979. More recently, the team at Phil Fraley Productions disassembled and restored the Apatosaurus, along with the rest of the classic CMNH dinosaurs. Since 2007, this specimen has been back on display in a more graceful modern pose.

Fancy fisheye photo.

AMNH Barosaurus. Source

Barosaurus lentus – AMNH 6341

When the CMNH team discovered this skeleton in 1912, they assumed it was yet another specimen of the well-known Diplodocus. It was harvested for parts, with portions sent to CMNH, the United States National Museum, and the University of Utah to supplement their displays. When the specimen turned out to be the more obscure sauropod Barosaurus, it languished in pieces for many years. Barnum Brown of AMNH was making a circuit of the fossil collections at various natural history museums when he rediscovered this specimen. Through a series of purchases and trades, the Barosaurus was reunited at AMNH in 1929.

Nevertheless, AMNH quickly abandoned plans to mount the Barosaurus – the museum already had a sauropod on display, and there wasn’t enough floor space for another one. It wouldn’t go on display until 1991, when Lowell Dingus conceived of the idea to mount the Barosaurus in a spectacular rearing pose as part of the renovation of the Theodore Roosevelt Rotunda. Peter May took on the project – one of the first mounts produced by his company Research Casting International. The resulting display, actually a cast, is the tallest free-standing dinosaur mount in the world.

ROM Barosaurus.

ROM Barosaurus. Source

Barosaurus lentus – ROM 3670

Douglass recovered a second partial Barosaurus skeleton in 1912, which consisted of a mostly complete torso and parts of each leg. It stayed in the CMNH collections for many years, until they traded it to the Royal Ontario Museum in 1962. ROM staff intended to mount the skeleton, but once again this was cancelled due to a lack of space. David Evans was developing a new ROM paleontology exhibit in 2007 when he learned that the museum had most of a Barosaurus sitting in its collections. With only weeks remaining before the exhibit’s opening, Evans tapped Research Casting International to mount the sauropod, supplemented with a replica neck and tail from the AMNH version.

Allosaurus fragilis – CM 11844

Several Allosaurus specimens are known from the Carnegie Quarry, but the one on display at CMNH is one of the largest. Douglass and his team excavated this 35-foot skeleton between 1913 and 1915. The mount was built in 1938. Although the specimen included a partial skull, the exhibit team swapped it with a cast of a more complete skull (also found in the Carnegie Quarry) from the collections of the University of Utah. This mount also includes casts of the arms of USNM 4734, an Allosaurus collected for O.C. Marsh.

Stegosaurus ungulatus – CM 11341

The CMNH Stegosaurus is a composite of several individuals excavated from the Carnegie Quarry between 1920 and 1922. Museum staff completed the 21 foot-long mount in 1940, using a skull cast from USNM 8612. Casts of this skeleton were distributed to several other museums at some point, one of which is on display at the University of Nebraska State Museum. Phil Fraley’s company remounted the CMNH original in 2007.

Carnegie Camarasaurus.

Carnegie Camarasaurus. Source

Camarasaurus lentus – CM 11338

This juvenile Camarasaurus is the most complete sauropod ever found. It is displayed as a relief mount almost exactly as it was discovered, with two exceptions. The left leg was swapped with a more complete one from another individual, and the tail was re-positioned to create a more aesthetically pleasing mount. Casts of this skeleton are displayed at museums throughout the United States, including Dinosaur National Monument, but the original is at CMNH. This specimen is also notable because its left scapula is preserved in its life position, making it a helpful model for skeletal reconstructions and exhibit mounts.

NMNH Camarasaurus. Photo by the author.

NMNH Camarasaurus. Photo by the author.

Camarasaurus lentus – USNM 13786

The second best Camarasaurus also comes from Carnegie Quarry, but it is a considerably larger individual. Only the tail and a few odds and ends were missing. CMNH kept the specimen for several years before trading it to USNM in 1933 for a set of Pliocene horse skeletons. Norman Boss prepared the specimen in full view of the public during the 1936 Texas Centennial Exposition – one of the first known examples of such an exhibit. The completed mount appeared at USNM in the 1950s, sporting the tail of another Camarasaurus. At over 30 feet long, this skeleton is one of the largest dinosaurs on display at the Smithsonian. Unfortunately, the death pose somewhat limits the effect. The Camarasaurus was taken off exhibit in late 2014 for conservation and remounting. When it returns, it will be standing on its feet for the first time in 150 million years, taking its rightful place as one of the museum’s most impressive dinosaurs.

DMNH Diplodocus. Source

DMNH Diplodocus. Source

Diplodocus longus – DMNH 1494

Since this Dipldodocus was found somewhat disarticulated, Douglass suggested that the carcass may have been twisted apart while rolling downstream. AMNH held on to this skeleton for some time before trading it to the Denver Museum of Nature and Science in 1936 for two mammoth skeletons. Preparator Phillip Reinheimer mounted the skeleton with the help of 40 workers assigned to the museum through the Works Progress Administration. Additional Diplodocus fossils collected by William DeWeese (actually the first dinosaur specimens acquired by the museum) were also used to complete the mount. The Diplodocus remained on view until 1989, when Ken Carpenter and others restored and remounted the sauropod, elevating its tail and making its neck sweep gracefully to the left. The improved mount has been on display since 1995.

CMNH Camptosaurus.

CMNH Camptosaurus. Historic photo from McGinnis 1982; modern photo source.

Camptosaurus aphanoecetes – CM 11337

Douglass found this controversial small ornithopod in 1922, and correctly matched it with an isolated leg several feet away. It was first identified as Camptosaurus medius, but in 2008 Ken Carpenter reassigned it to the new species C. aphanoecetes. A 2011 phylogenic study by Andrew McDonald moved this specimen to a new genus, Uteodon. Carpenter, however, asserts that McDonald’s analysis was based on an incorrectly associated Dryosaurus braincase.

CMNH staff assembled the fossils into a relief mount in 1940. The skull, hindfeet, and tail were all sculpted. During the 2007 renovation, the Phil Fraley Productions team extracted the fossils from the plaster slab, even managing to preserve the delicate ossified dorsal tendons. They then created a new, three-dimensional mount, which features a revised replica skull.

Modern photo by the author.

CMNH Dryosaurus. Historic photo from McGinnis 1982; modern photo by the author.

Dryosaurus altus – CM 3392

This Dryosaurus skeleton is the most complete of several collected at Dinosaur National Monument. The tail is missing, and given the completeness of the rest of the skeleton it may well have been destroyed when Douglass’s crew was blasting through rock to get to the bone layer. The Dryosaurus entered the CMNH collections in 1922, and was assembled as a 9 foot-long relief mount in 1940. In 2007, Fraley’s team removed the fossils from the plaster matrix, and just as they did with the Camptosaurus, constructed a standing mount. To date, this is the only mounted Dryosaurus specimen in the world. It is displayed alongside a juvenile Ceratosaurus cast acquired from Western Paleontological Laboratories.

National Museum of Natural History in Washington, DC.

NMNH Diplodocus. Photo by the author.

Diplodocus sp. – USNM 10865

The National Museum of Natural History’s Diplodocus was one of the last articulated skeletons removed from the Carnegie Quarry. When the CMNH crew closed up shop, Charles Gilmore of the Smithsonian moved in to recover one of the sauropod skeletons Douglass left behind. In 1923, Gilmore’s team excavated a partial Diplodocus, and also cherry-picked a few extra bones from an adjacent specimen. The process of mounting the skeleton at USNM took six years of continuous work, and Gilmore would later describe it as the most ambitious undertaking his department hadever attempted. The 70-foot Diplodocus mount was completed in 1931, and remained unchanged for more than 80 years. It was finally taken down in December 2014, and will return in a new pose in 2019.

Addendum: Mike Taylor recently called attention to a gorgeous map of the entire deposit prepared by Ken Carpenter, which was what prompted this post. Check it out here.

References

Carpenter, K. (2013). History, Sedimentology, and Taphonomy of the Carnegie Quarry, Dinosaur National Monument, Utah. Annals of the Carnegie Museum 81:3:153-232.

Dingus, L. (1996). Next of Kin: Great Fossils at the American Museum of Natural History. New York, NY: Rizzoli International Publications, Inc.

Gilmore, C.W. (1941). “A History of the Division of Vertebrate Paleontology in the United States National Museum.” Proceedings of the United States National Museum 90.

McGinnis, H.J. (1982). Carnegie’s Dinosaurs: A Comprehensive Guide to Dinosaur Hall at Carnegie Museum of Natural History, Carnegie Institute. Pittsburgh, PA: The Board of Trustees, Carnegie Institute.

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Filed under AMNH, CMNH, collections, dinosaurs, DMNS, exhibits, field work, fossil mounts, history of science, museums, NMNH, ornithopods, sauropods, theropods, thyreophorans