Category Archives: ornithopods

The retiring dinosaur mounts at the Yale Peabody Museum

Another year, and another major renovation of a historic paleontology exhibition is underway. The dinosaur and fossil mammal halls at the Yale Peabody Museum of Natural History (YPM) closed to the public on January 1st. The rest of the museum will follow in July, with a planned reopening in 2023. This will be the first comprehensive renovation of the museum since the current building opened in 1931, and the upgrades are long overdue. For decades, most of the YPM exhibits have been a museum of a museum—a time capsule preserving the state of natural science and museum design in the mid-20th century. The dinosaur hall in particular looks almost exactly as it did when Rudolph Zallinger completed the spectacular Age of Reptiles mural on the east wall in 1947 (a handful of newer specimens, revised labels, and video terminals notwithstanding).

The Great Hall of Dinosaurs upon my last visit in 2014.

It’s exciting to see ground breaking on the new museum and exhibits, because this renovation has been a long time in coming. Serious discussions were underway in 2010, if not earlier, and a set of conceptual images was released as part of a fundraising effort launched in 2013. It appears that a lot has changed since then. The scope of the renovation has expanded to encompass the whole museum, not just the paleontology exhibits. And certain details from the 2013 concept—such as a mezzanine in the dinosaur hall opposite the Age of Reptiles mural—have been dropped. Last year, YPM launched a dedicated website showcasing the latest renovation plans. It’s wonderful that the institution is committed to keeping their community involved in and informed about the transformation of a public space that is near and dear to so many.

Naturally, this renovation is an opportunity to take a deep dive into the YPM fossil displays, and look at the specimens, artwork, and people that defined this institution in the past and which will carry it into the future. Expect upcoming posts exploring the future of these exhibits, but for now let’s start with a look back at the exhibit that once was.

Rendering of the new dinosaur hall, as of late 2019. Source

YPM was founded in 1866 with a gift from George Peabody. Peabody was the uncle of O.C. Marsh, who had been appointed Professor of Vertebrate Paleontology at Yale that same year. Having been awarded tenure and his own museum, Marsh began to lead and send crews into the American west to collect fossils. Many of Marsh’s expeditions were under auspices of the U.S. Geological Survey, and those fossils eventually made their way to the Smithsonian. The remainder, however, entered the YPM collections, where they remain to this day.

After Marsh’s death in 1899, his student Charles Beecher took over vertebrate paleontology at YPM. Beecher was, in turn, succeeded by Richard Lull. Lull never met Marsh (and the two were quite different in many ways), but he nevertheless spent much of his career carrying on his predecessor’s legacy. Like his Smithsonian counterpart Charles Gilmore, Lull expanded Marsh’s often laughably brief descriptions into proper monographs, which are still used by paleontologists today. And like Gilmore, Lull put the Marsh fossils on public display, guiding the assembly of the mounted skeletons that have held court at YPM ever since.

Lull became director of YPM in 1922, and it was in this role that he oversaw the museum’s move from it’s modest original building to the larger, French Gothic-inspired structure where it currently resides. Construction of the new museum was completed in 1925, and Lull spent the next several years developing the dinosaur hall we know today. Marsh, for his part, disliked the idea of display mounts, considering it a waste of time and effort. And limited space at the old facility meant that only two large dinosaur mounts—Edmontosaurus and Stegosaurus—were assembled between 1900 and 1925. The new building, however, had a great hall specifically built to house the Marsh dinosaurs, so Lull and his team got to work filling it.

Camarasaurus and Camptosaurus

Camarasaurus and Brontosaurus mounted skeletons.

Most of the new mounts were assembled from fossils collected around 1880 at Como Bluff, Wyoming. Working for Marsh, William Reed and his crew amassed a treasure trove of Jurassic dinosaurs there, most famously the Brontosaurus holotype. Naturally, Lull devised Brontosaurus (YPM 1980) as the centerpiece of the dinosaur hall. Because of its size and complexity, it was the first of the new mounts to begin construction and took the longest to complete. The Brontosaurus was literally built into the floor: photos from the 1920s show a latticework of steel beams designed to spread its weight. Once the floor was installed, the Brontosaurus could not be moved.

In the meantime, preparator Hugh Gibb assembled two other mounts from Como Bluff material: Camarasaurus and Camptosaurus. The Camarasaurus (YPM 1910) is 21-foot juvenile, consisting of a complete vertebral column from the 2nd or 3rd cervical to middle of the tail, and most of the larger limb bones. The feet and most of the ribs are reconstructed, as is the skull, which is a fairly crude sculpture. In his 1930 publication discussing the mount, Lull commends Gibb for how closely his reconstruction matched the nearly complete and articulated juvenile Camarasaurus collected by the Carnegie Museum at what is now Dinosaur National Monument, despite the fact that Gibb had never studied that specimen. Lull only notes that the YPM mount has one fewer cervical and one fewer caudal than the Carnegie specimen, and that the reconstructed cervical ribs are much too short.

Camptosaurus and Camarasaurus mounted skeletons.

Gibb also assembled the Camptosaurus mount (YPM 1880), which he completed in 1937. Yet another specimen from Reed’s excavations at Como Bluff, the Camptosaurus is notable for how closely it mirrors Marsh’s illustrated reconstruction from 40 years earlier. It seems reasonable to assume this was a deliberate homage, although Gibb did follow Gilmore’s example and removed Marsh’s erroneous lumbar vertebrae. The sculpted skull, modeled after Iguanodon, was typical of Camptosaurus reconstructions at the time but is now known to be inaccurate.

Neither Camarasaurus nor Camptosaurus are slated to return in the renovated exhibit. Marsh originally designated both of these specimens as holotypes for “Morosaurus” (=Camarasaurus) lentus and Camptosaurus medius. Opinions on the validity of those particular species have changed over time, but it’s important that a new generation of paleontologists has an opportunity to study the original fossils up close, which has been virtually impossible in their mounted form.

Claosaurus

Relief mount of Claosaurus.

High on the west wall is one of YPM’s most overlooked dinosaurs. This relief mount represents the only confirmed remains of Claosaurus agilis (YPM 1190), a hadrosaur found in the marine deposits of western Kansas. Claosaurus is a bit of a taxonomic mess: Marsh initially announced this fossil as a new species of Hadrosaurus, before upgrading it to its own genus. Then, he decided to sink all of the much younger Lance Formation hadrosaur material (what is now called Edmontosaurus annectens) into the Claosaurus genusIt’s a difficult web to untangle, but Claosaurus is a real taxon that lived alongside animals like Pteranodon and Tylosaurus.

Lull and Wright describe the mount as “recent” in their 1942 monograph on hadrosaurs, so it must have been assembled after the move the current building. Most of the vertebrae and limb bones are real, but the skull is (obviously) a model built around a few fragments of jaw. Although it’s hard to see from the ground, the preservation is apparently poor, and most of the bones are crushed to some degree. Lull and Wright attest to the significance of Claosaurus as the earliest known true hadrosaur, but were clearly frustrated by the quality of the specimen. Perhaps modern paleontologists will have better luck, once it’s taken off display and returned to the collections.

Centrosaurus

The Centrosaurus half-mount and its Cretaceous buddies.

Variably known as Monoclonius flexus, Centrosaurus flexus, and Centrosaurus apertus, this ceratopsian skeleton (YPM 2015) was collected by Barnum Brown on the American Museum of Natural History’s extremely productive expeditions to the Belly River region in Alberta. I’m not sure when YPM acquired the fossil (presumably in a trade), but it was mounted and on display by 1929. At some point during the development of the fossil mammal hall, Lull became enamored of half-mounts like this one, in which the animal appears bisected along its sagittal line. Half the skeleton is assembled on one side, while a fleshed-out model is visible on the other. Several mammal specimens at YPM are displayed this way, but the Centrosaurus is the only dinosaur.

Lull discusses the choices made in reconstructing Centrosaurus at length in his 1933 monograph on ceratopsians. He describes the relief-mounted Centrosaurus at AMNH as an imperfect representation of the animal’s life appearance because it preserves the death pose it was found in. In contrast, the YPM version is reconstructed in a three-dimensional standing posture. Lull specifically points to his Centrosaurus‘s nearly straight neck and sprawling forelimbs (with the humerus nearly horizontal) as superior to the AMNH presentation. The issue of ceratopsian forelimb posture is still not completely resolved, but there is probably some truth to Lull’s sprawling reconstruction.

The life-reconstruction side of Centrosaurus, as figured in Lull 1933.

For the fleshed-out portion of the mount, Lull directed the artist to match the musculature and skin texture of iguanas and alligators. A loggerhead turtle was referenced for the mouth and beak. Lull chose to give the small processes on the lower edges of the frill a horny sheath, rather than the fleshy look popularized by Charles Knight. Overall, the life restoration is on the lean side compared to our modern understanding of ceratopsians, but many details—including the digitigrade fingers and forelimb posture—have held up well.

Next time, we’ll look at how historic specimens like Brontosaurus, Stegosaurus, and Deinonychus might be modernized for the new version of the hall.

References

Lull, R.S. 1930. Skeleton of Camarasaurus lentus recently mounted at Yale. American Journal of Science 19:105:1-5.

Lull, R.S. 1910. Stegosaurus ungulatus Marsh, recently mounted at the Peabody Museum of Yale University. American Journal of Science 30:180:361-377.

Lull, R.S. 1933. A Revision of the Ceratopsia or Horned Dinosaurs. New Haven, CT: Tuttle, Morehouse, and Taylor Co.

Lull, R.S. and Wright, N.E. 1942. Hadrosaurian Dinosaurs of North America.  New York, NY: Geological Society of America.

Marsh, O.C. 1872. Notice on a new species of Hadrosaurus. American Journal of Science 3:16:301.

Marsh, O.C. 1890. Additional characters of the Ceratopsidae, with notice of new Cretaceous dinosaurs. American Journal of Science 39:233:418-426.

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Filed under dinosaurs, exhibits, museums, ornithopods, sauropods, YPM

One Year to Deep Time

When the fossil halls at the National Museum of Natural History closed for renovation in 2014, five years seemed like an interminable amount of time to wait for the reopening. But the NMNH crew has been hard at work, and suddenly the June 2019 debut of the new National Fossil Hall is almost in sight. I’ve mostly avoided reporting on each and every bit of information pertaining to the new exhibit, but as we approach the one-year-to-opening milestone the drip is likely to become a deluge. That means that this is probably a good time to do a round-up of everything that has been officially revealed about the new exhibit up to this point.

The East Wing Restored

The original architectural grandeur is back. Images from of the Smithsonian Institution Archives and the Washington Post.

The building that is now NMNH opened in 1910. Its granite-heavy, Beaux Arts construction was a departure from the Victorian style of the first United States National Museum, but it looked right at home with the other federal buildings around the National Mall. As originally designed, the building resembled a squat “T” from above, with three large wings (facing east, north, and west) extending from a central rotunda. The east wing — a vast space with bay windows, intricate plaster detailing, and a skylight three stories up — has always housed fossil displays. Over the course of the 20th century, however, the once spacious hall was repeatedly carved into smaller sections. Windows and architectural flourishes were covered up, and by the time the last round of renovations was completed in 1985 the east wing had become cramped and gloomy.

A major part of the current renovation has been returning the space to its original glory. Grunley Construction spent two years restoring and recreating the east wing’s 1910 architecture, as well as updating infrastructure and improving the space’s energy efficiency. Most of this process was visible via webcam. Last November, the Washington Post provided some stunning floor-level photos of the restored hall. Wide open and filled with natural light, the renovated hall is glorious to behold, even without the fossils.

A Story of Environmental Change

Many exhibits and books about paleontology portray the evolution of life as though it occurred in a vacuum. In fact, the evolution of animals and plants is primarily driven by environmental upheaval — changing climate, shifting geography, and so forth. Sometimes this relationship goes the other way, and keystone organisms (such as grass in the Neogene or humans in the present day) drastically change the world around them. Environmental change over time is at the heart of the National Fossil Hall’s story. It’s worth quoting the official theme statement in full:

Visitors to the Museum will be able to explore how life, environments, and ecosystems have interacted to form and change our planet over billions of years. By discovering and harnessing the tools and methods paleobiologists use to study fossils, visitors will gain a deeper understanding of how the world works.

The distant past affects all of us today and will continue to do so in the future. How will climate change impact the natural world and our daily lives? How can we make informed choices about our ecosystems as individuals and as a species? How can we all become informed citizens of a changing planet?

These themes are reflected by the physical layout of the exhibit, which is chronological but not strictly proportional. Specimens are clustered onto islands situated throughout the open floorplan, each representing North America at a particular point in time. While anchored by a few charismatic mounts, the islands also include all manner of small animals, invertebrates, and plants that were part of that environment. In this way, each island shows a complete ecosystem that existed at a particular time. Moving among these displays, visitors should get a sense of how phenomena like climate change and faunal interchange can completely transform an ecosystem over millions of years.

During the development process, curators and exhibit specialists agreed that the hall should not be an encyclopedia of past life. Instead, everything ties back to main story. Big, showy specimens like dinosaurs are contextualized as products of environmental change. Meanwhile, fossils that visitors might otherwise overlook but are critical to our understanding of ecological change over time, like pollen grains or leaves, are literally and figuratively pedestaled to emphasize their importance.

The Nation’s T. rex

The Nation’s T. rex, temporarily assembled in the Research Casting International workshop. Image by Great Big Story.

The centerpiece of the National Fossil Hall is a real Tyrannosaurus rex skeleton — the first real T. rex (as opposed to a cast) the Smithsonian has ever displayed. The specimen in question has been known as the “Wankel Rex” since it was discovered by avocational fossil hunter Kathy Wankel in 1988. It has been held in trust at Bozeman, Montana’s Museum of the Rockies, but since it came from Army Corps of Engineers land it is technically owned by the U.S. federal government. Although several casts of the Wankel Rex are on display around the world, the original fossils have never before been assembled into a standing mount. That’s changing now that the fossils have been transferred to the Smithsonian.

Curator Matt Carrano designed a deliriously cool pose, with the Tyrannosaurus poised as though prying the head off of a prone Triceratops. NMNH is visited by eight million people every year, so the Wankel Rex (now the Nation’s T. rex) will soon be the most viewed T. rex skeleton in the world. The Nation’s T. rex story has been covered by the Washington Post, NPR, National Geographic, and Smithsonian Magazine, among many others.

Poses that Show Behavior

The remounted mammoth demonstrates plausible behavior. Left image by the author, right image from Smithsonian Magazine.

Historically, mounted fossil skeletons were most often given anatomically neutral poses. This was a structural engineering necessity as much as it was a curatorial preference. However, modern technology has made it possible to safely display casts and even real skeletons in surprisingly dynamic poses. At many museums, this has usually manifested as mounted skeletons fighting or simply roaring at each other. In contrast, the NMNH team has endeavored to create dynamic mounts that show a greater variety of interesting behavior evidenced by the fossil record. For example, the remounted mammoth (shared during a talk by NMNH Director Kirk Johnson) is pushing its tusks along the ground, as if clearing snow off the grass. The Allosaurus (headless in the right image) is crouching next to a nest mound. Even the aforementioned T. rex and Triceratops scene is inspired by real research into T. rex feeding mechanics.

The Anthropocene

Most exhibits about the history of life close at some point in the past, but the National Fossil Hall continues the story into the present day. We are in the midst of an extinction event of our own making, and anthropogenic climate change, habitat destruction, and invasive species are as dangerous as any asteroid. During our very limited time on Earth, humans have altered the climate, the rate of erosion, and the acidity of oceans. Whether or not you think adopting “Anthropocene” as a formal geologic unit is reasonable, we have inarguably changed the planet in geologically measurable ways.

Curator Scott Wing discussed his approach to interpreting the age of humans in a Geological Society of America talk and in an Earth Matters blog post. The key is to make it clear that in spite of our destructive potential, humans have the power to mitigate and manage the consequences of altering the world around us. The exhibit will show visitors how they can take responsibility for humanity’s collective legacy.

Marsh Dinosaurs Re-imagined

An updated Stegosaurus replaces the 2004 cast, which replaced the original 1913 mount. Images from the Smithsonian Institution Archives and Kirk Johnson on twitter.

The new Edmontosaurus cast replaces the original mount, which had gone unmodified since 1904. Images by NMNH Paleobiology and Will S.

Most of the dinosaur skeletons exhibited at NMNH were assembled before 1920. Originally excavated by O.C. Marsh’s crews in the 19th century, these specimens have gone on to lead second lives on display, and have been seen by generations of visitors. Nevertheless, time has taken its toll. Some mounts have been rendered out-of-date by new discoveries, while others have gradually deteriorated due to fluctuating temperature and humidity, not to mention constant vibration from passing crowds. Before the fossil halls closed in 2014, NMNH preparators had already dismantled three historic dinosaurs (Triceratops, Stegosaurus, and Camptosaurus) and replaced them with updated casts. Returning these fossils to the collections ensures their continued safety, while also giving paleontologists a chance to study them for the first time in decades.

The renovation has been an opportunity to give other at-risk specimens the same treatment. It was especially important to get the real Ceratosaurus, Edmontosaurus, and Thescelosaurus skeletons off the exhibit floor because these are all holotypes — the original specimens that were used to define the species. Set in plaster on the exhibit walls, these important skeletons were virtually inaccessible. And as the preparators discovered when they removed them, they had not even been fully extracted from the rock they were found in. The real fossils are now available for research, while casts with lively poses and up-to-date anatomy will take their place on display (before anyone panics, the new exhibit will still feature several real dinosaur skeletons).

The Pocahontas Mine

As reported by the Bluefield Daily Telegraph, a Smithsonian crew of paleobotanists, geologists, and exhibits specialists visited the historic Pocahontas Exhibition Mine last November. This coal mine near Pocahontas, Virginia operated from 1882 to 1938, when ceased production and became a tourist attraction. The Smithsonian crew took photographs, video, and silicon molds of the mine’s walls, which are covered with Carboniferous-era plant impressions. A reconstruction of the fossiliferous mine will anchor the Carboniferous section of the exhibit.

Treasures from the Collection

A near-perfect Ophiacodon from Texas. Photo via the NMNH Department of Paleobiology.

A typical natural history museum has less than one percent of its collection on display at any time, and NMNH is no exception. In addition to introducing brand-new specimens and updating old ones, the renovation is an opportunity to bring a variety of never-before-displayed objects from the collections to the display floor. Of the hundreds of specimens earmarked for display, I can only highlight a few.  There’s the historic cast of the plesiosaur Rhomaleosaurus, which has been in the collection since 1895 but never displayed. There’s the skull of the tusked whale Odobenocetops, which preparator Michelle Pinsdorf profiled in a webcast last year. Carrano showed NPR’s Adam Cole a sauropod osteoderm, collected decades ago but only identified recently. And then there’s the near-perfect Ophiacodon pictured above, collected in 1988 by Arnie Lewis and Nicholas Hotton. I remember this guy from my intern days, when it was referred to as “sleeping beauty.”

Research Casting International will start installing the large skeletons this summer, and then the countdown to opening day begins in earnest. Here’s wishing the NMNH team all the best as their years of work finally comes to fruition!

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

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 colossal Eremotherium completely overshadows 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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AMNH dinosaurs in vintage cartoons

Today I happened upon a pair of wonderful vintage cartoons that simply must be shared. I found them in Edwin Colbert’s The Dinosaur Book: The Ruling Reptiles and Their Relatives, digitized here. The cartoons originally appeared in the New Yorker and the Saturday Evening Post, respectively.

original caption

Original caption: “And here is my first dinosaur – makes me feel like a kid again every time I look at it.”

The cartoons plainly depict the “Brontosaurus” and “Trachodon” (now labeled Apatosaurus and Anatotitan) skeletons at the American Museum of Natural History, and as representations of these mounts, they aren’t bad. At the time of the cartoons’ initial publications in 1939 and 1940, these and dozens of other fossil mounts had been on display at AMNH for over 30 years. They were iconic New York attractions, and the museum had rightly earned itself a reputation as the place to see dinosaurs.

original caption

Original caption: “I don’t mind you boosting your home state, Conroy, but stop telling the children that’s a California jack rabbit!”

Perhaps it’s unwise to interpret these images too literally, but I can’t help but wonder which version of the AMNH fossil halls the cartoonists intended to depict. Since 1922, the famous mounts had been housed in Henry Osborn’s Great Hall of Dinosaurs, but during the 1930s the dinosaur exhibits underwent a significant expansion. The dinosaurs were reshuffled into two halls, one representing the Jurassic and one the Cretaceous.

osborn era

The Great Hall of Dinosaurs as it appeared in the 1920s. Image courtesy of the AMNH Research Library.

brown's jurassic hall

The new Jurassic Hall opened around 1940. Photo from Dingus 1996.

The inclusion of a Stegosaurus with “Brontosaurus” and the ceratopsian skulls behind the “Trachodon” lead me to believe these are illustrations of the renovated halls, which would have been brand new at the time. But again, it’s just as likely that the cartoonists only intended to capture the general feel of these famous exhibits.

References

Colbert, E.H. 1945. The Dinosaur Book: The Ruling Reptiles and Their Relatives, 2nd Edition. New York, NY: The American Museum of Natural History/McGraw-Hill Book Company, Inc.

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

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Was the Hawkins Hadrosaurus real?

Photo from Weishampel and Young 1996.

Hadrosaurus at the Academy of Natural Sciences. Photo from Weishampel and Young 1996.

In the “Claosaurus” post earlier this week, I temporarily(?) lost my mind when I said that the Hadrosaurus Benjamin Waterhouse Hawkins assembled for the Academy of Natural Sciences was 100% plaster reconstruction. Thanks to John Sime, among others, for pointing out that this was incorrect. As usual, the truth is more complicated, and therefore much more interesting.

The Hadrosaurus project began when Hakwins was commissioned to create a series of life-sized prehistoric animals for display in New York City’s central park, under the direction of Joseph Leidy. The exhibition was cancelled when Hawkins’ on-site workshop was burned down by vandals, but he was able to salvage the Hadrosaurus skeleton for display at the Academy in Philadelphia. This reconstruction was based on little more than two limbs and a handful of vertebrae. It was a well-reasoned attempt – and it drew huge crowds – but it wasn’t long before new dinosaur finds rendered it obsolete. In 1901, Charles Beecher wrote that the Hadrosaurus mount had “long since ceased to have any value or interest except as a historical attempt.” No longer considered informative, the original Hadrosaurus was probably dismantled around the start of the 20th century. At least three plaster copies were distributed to other museums, but these were also discarded long ago.

There is no question that Hawkins’ reconstruction doesn’t reflect our present understanding of this animal, so in that sense it isn’t “real.” Still, it is of historic interest whether Hawkins used the handful of original Hadrosaurus fossils in the mount itself, or whether the entire display was fabricated. There is precedent for both posibilities: John Peale mounted an original mastodon skeleton in 1802, but the Smithsonian’s first attempts at Basilosaurus and Triceratops (1895 and 1900 respectively) included no real fossils. This question was actually up for discussion as early as 1926. Responding to an inquiry from Peabody Museum paleontologist Richard Lull, Academy of Natural Sciences curator Witmer Stone wrote that the Hadrosaurus mount was a complete reproduction. When Lull followed up with William Matthew of the American Museum of Natural History, however, Matthew recalled that “some or all of the original bones were used.”

The two letters reproduced below are in the collection of the Department of Vertebrate Paleontology Archives at the Peabody Museum of Natural History, and are shared with permission.

courtesy

Letter from Witmer Stone to Richard Lull, January 26, 1925. Courtesy of the Dept. of Vertebrate Paleontology Archives, Yale Peabody Museum of Natural History.

Courtesy

Letter from William Matthew to Richard Lull, January 30, 1925. Courtesy of the Dept. of Vertebrate Paleontology Archives, Yale Peabody Museum of Natural History.

A look at the original Hadrosaurus fossils, now cataloged as ANSP 10005, suggests that Matthew was correct. At least a couple of the bones appear to bear drill holes, a tell-tale sign that they were once fastened to an armature. Likewise, in a photograph of the mount in Hawkins workshop, the elements that were actually recovered – the left leg*, part of the pelvis, and a scattering of vertebrae – appear to be darker in color. This suggests that these are the real bones, and the rest of the skeleton is plaster…unless Hawkins painted plaster casts to demonstrate which elements had been found.

*Note that the image below has been flipped horizontally for some reason. In the original, the left side of the skeleton is facing the camera.

Hawkin's studio

Hadrosaurus in Hawkins’ studio. Image from Carpenter et al. 1994.

The answer to this little conundrum can be found in the official guidebook to the Academy of Natural Sciences, published in 1879. Apparently there were two versions of Hadrosaurus on display. The original 1868 mount did include the original fossils, but when the museum moved to a larger facility in 1876 (in part because of the spike in visitation caused by the Hadrosaurus exhibit) the mount was remade. The bones were not faring well in open air and were rapidly deteriorating, so they were retired to the collections and replaced with casts. Anyone who saw the Hadrosaurus before 1876 saw the fossils incorporated into the mount, and anyone who visited later saw a complete facsimile. Still, I’m pretty sure William Matthew was remembering incorrectly. He was born in 1871, so unless he was carefully observing the composition of the mount at age 5, he shouldn’t have seen the original version!

References

Beecher, C.E. 1901. The reconstruction of a Cretaceous dinosaur, Claosaurus annectens Marsh. Transactions of the Connecticut Academy of Arts and Sciences. Vol. 11, pp. 311-324.

Carpenter, K., Madsen, J.H. and Lewis, L. 1994. Mounting of Fossil Vertebrate Skeletons. Vertebrate Paleontological Techniques, Vol. 1. Cambridge, UK: Cambridge University Press.

Prieto-Márquez, A., Weishampel D.B., and Horner J.R. 2006. The dinosaur Hadrosaurus foulkii, from the Campanian of the East Coast of North America, with a re-evaluation of the genus. Acta Palaeontologica Polonica. Vol. 51, pp. 77-98.
Ruschenberger, W.S.W. and Tryon, G.W. 1879. Guide to the Museum of the Academy of Natural Sciences of Philadelphia. Philadelphia, PA: Academy of Natural Sciences.
Weishampel. D.B. and Young, L. 1996. Dinosaurs of the East Coast. Baltimore, MD: The Johns Hopkins University Press.

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Beecher’s “Claosaurus”

Readers are likely aware that the Hadrosaurus Benjamin Waterhouse Hawkins created for the Academy of Natural Sciences was the first mounted dinosaur skeleton. It is less widely known, however, that this Hadrosaurus was a plaster facsimile, which included none of the actual fossils that inspired it. (edit: not quite, see comments). The title of first dinosaur mount composed of original fossils belongs to the Belgian Iguanodon assembled by Louis Dollo in 1891 (I should probably write about this eventually, but Fernanda Castano has an excellent account at Letters From Gondwana). So what was the first real fossil dinosaur mount on this side of the Atlantic? Glad you asked – that would be none other than the 1901 Edmontosaurus at the Peabody Museum of Natural History.

Edmontosaurus is surprisingly modern

The PMNH Edmontosaurus with Deinonychus and Centrosaurus. Photo by the author.

There are plenty of Edmontosaurus skeletons on display today, but the Yale mount is noteworthy because of its remarkably modern appearance. While the Hawkins Hadrosaurus and Dollo Iguanodon were upright tail-draggers, the Edmontosaurus could be mistaken for a mount constructed in the last quarter century. Its raised tail, horizontal posture, and energetic gait all reflect current thinking about dinosaur posture and locomotion. And yet, it was built at the turn of the century, back when paleontologists supposedly all thought of dinosaurs as lethargic lizards.

The Hawkins Hadrosarus and Dollo Iguanodon. Photos from

The Hawkins Hadrosarus and Dollo Iguanodon. Images from Paper Dinosaurs.

The scientist behind this mount was Charles Beecher. Born in Pennsylvania, Beecher studied at the University of Michigan before taking an Assistant of Paleontology position at Yale in 1888. He completed his PhD under Marsh, who apparently thought highly of him (and Marsh didn’t think highly of many people). Although his preferred research subjects were Paleozoic invertebrates, Beecher could be counted on to help prepare his mentor’s vast collection of dinosaur fossils, when needed. When Marsh died in 1899, Beecher succeeded him as the head of the Peabody Museum, and set himself the task of mounting one of the institution’s best dinosaur specimens for display.

Beecher selected YPM VP 2182 as the Peabody Museum’s first fossil mount because it was nearly complete and mostly articulated. Known to Marsh and Beecher as “Claosaurus” annectens*, this Edmontosaurus skeleton was collected in Wyoming by John Bell Hatcher (because of course it was). Beecher and assisting preparator Hugh Gibb attempted to preserve the fossils within their original matrix as much as possible. Since the specimen was somewhat laterally compressed, Beecher kept the right side mostly in situ and built up the left in high relief. The head and neck were technically never removed from their matrix block, but since the head was found curved under the body it had to be rotated into its life position. All told, only the right ribs, the corocoids, the final two-thirds of the tail, and some of the vertebral processes were reconstructed. No attempt was made to restore the ossified dorsal tendons, which were poorly preserved on this specimen.

woo

Beecher’s Edmontosaurus, ca. 1917. Source

The complete mount is 13 feet tall and 29 feet long, its tail extending past the edge of the 27 foot slab. For a few years, it was the largest fossil mount ever built. The slab itself is made up of original matrix blocks sealed together with a manufactured surface created from plaster, resin, and ground Laramie Formation sandstone. It was assembled in four pieces secured to wooden frames. These were designed to be separated and moved with relative ease, although PMNH staff have yet to try.

According to Beecher, he imbued the Edmontosaurus with its lively pose in order to preserve the in situ orientation of the pelvis and left femur. It is worth quoting Beecher’s 1901 description of the mount in full:

“It is intended that this huge specimen should convey to the observer the impression of the rapid rush of a Mesozoic brute. The head is thrown up and turned outward. The jaws are slightly separated. The forearms are balancing the sway of the shoulders. The left hind leg is at the end of the forward stride and bears the entire weight of the animal. The right foot has completed a step and has just left the ground preparatory to the forward swing. The ponderous and powerful tail is lifted free and doubly curved so as to balance the weight and compensate for the swaying of the body and legs. The whole expression is one of action and the spectator with little effort may endow this creature with many of its living attributes.”

Much like the AMNH Gorgosaurus, the Yale Edmontosaurus demonstrates that early 20th century paleontologists’ supposed aversion to energetic and agile dinosaurs has been grossly overstated. Beecher saw Edmontosaurus as a powerful, active animal, and actually criticized the earlier reconstructions by Hawkins and Dollo. He correctly pointed out that the back-swept ischia of ornithopod dinosaurs would not allow room for the drooping tails they had reconstructed, and also noted that fossilized dinosaur trackways never show the mark of a dragging tail.

In the great hall of dinosaurs

Edmontosaurus as presently displayed in the Great Hall of Dinosaurs. Source

Beecher died suddenly in January of 1904, and the Edmontosaurus display ended up being one of his final professional accomplishments. Despite the relative dearth of dinosaur material available at the time, Beecher’s careful and impartial study of the available evidence allowed him to reconstruct this animal in a way that is still considered accurate 114 years later. Beecher’s work shows us that old research isn’t necessarily outmoded. Good science can come from any age and any source, if one only takes the time to look.

*Today, the genus Claosaurus is reserved for Claosaurus agilis from Kansas. The referred species annectens has since been placed in Thespesius, Trachodon, Anatosaurus, and now Edmontosaurus.

References

Beecher, C.E. 1901. The reconstruction of a Cretaceous dinosaur, Claosaurus annectens Marsh. Transactions of the Connecticut Academy of Arts and Sciences. Vol. 11, pp. 311-324.

Jackson, R.T. 1904. Charles Emerson Beecher. The American Naturalist. Vol 38, No. 450.

Marsh, Othniel C. 1892. Restorations of Claosaurus and Ceratosaurus. American Journal of Science. Vol. 44, pp. 343-349.

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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