Category Archives: marginocephalians

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

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

The Pan-American Expo Triceratops Lives On UPDATE: Or does it?

Triceratops at the Natural History Museum, London.

Triceratops at the Natural History Museum, London. Source

Don’t you hate it when you miss something glaringly obvious? I’ve never seen the Triceratops skeleton at London’s Natural History Museum in person, but I’ve seen enough pictures to know that it’s a little weird. Inaccuracies like the columnar feet, dragging tail, and vertical forelimbs can be attributed the display’s age, but the head doesn’t really look like any other Triceratops skull that’s ever been found. I had assumed that the funky frill and extremely long nasal horn were sculpted flourishes, but it turns out that no part of this Triceratops is real. It’s not a heavily-reconstructed original skeleton or even a cast – it’s a papier mâché model. And not just any model, but one that I’ve already written about in a different context.

Pan American exhibition

The Lucas Triceratops model at the 1901 Pan-American Exhibition. Source

Frederic Lucas, an Assistant Curator at the United States National Museum, created this Triceratops in 1900 for the Smithsonian display at the Pan-American Exhibition in Buffalo, New York. A mix of corporate and government displays based around the themes of peace, prosperity, and technology, the Pan-American Exhibition lasted from May to November 1901 (it was cut short when President William McKinley was shot on the fairgrounds). The Smithsonian’s 7,500 square foot exhibit took nearly a year to prepare, and showcased specimens from all departments of the nascent institution. Indeed, the Smithsonian’s participation in this and other fairs around the turn of the century is significant because these attractions were the basis for the some of the first exhibits at the USNM. Displays initially created for fairs often found a home in the museum’s permanent galleries, and the fair exhibitions were generally used as a template for the first generation of Smithsonian exhibits.

The Triceratops model was meant to represent the glut of fossils from the western United States that the Smithsonian had recently acquired from O.C. Marsh. Perhaps because most of those specimens were still unpacked and unprepared (the USNM didn’t hire a dedicated fossil preparator until 1903), Lucas sculpted the skeleton freehand based on one of Marsh’s published illustrations. It’s noteworthy that Lucas was not a paleontologist – he was brought on board at the age of 21 with no formal training because of his talent for constructing taxidermy displays. At any rate, Lucas followed Marsh’s reconstruction – at the time the only Triceratops reconstruction available – religiously when constructing his full-sized model.

St. Louis Expo

The Lucas Triceratops at the Louisiana Purchase Exposition in 1904. Source

After the Pan-American Exhibition, Lucas’s Triceratops made a second appearance at the 1904 Louisiana Purchase Exposition in St. Louis, Missouri. It was rendered obsolete shortly thereafter when Charles Gilmore assembled the world’s first real Triceratops skeleton at the USNM. As I’ve covered before, the act of physically manipulating the Triceratops fossils into a standing mount showed Gilmore that Marsh’s straight-legged reconstruction was a physical impossibility.

My understanding was that the Lucas model was lost or destroyed shortly after Gilmore’s real Triceratops went on display in 1905. I should have been more skeptical, however, because exhibits like this are almost never wasted. For example, Gilmore reported in 1943 that the Hadrosaurus cast displayed at the USNM before his arrival had been discarded due to wear and tear, but the mount had actually been given to the Field Museum in the 1890s. A couple months ago, I found out that Albert Koch’s chimeric mastodon (what he called “Missourium”) was purchased by Richard Owen on behalf of the British Museum and remounted. And just this year, the Smithsonian’s 112 year-old Stegosaurus model began a new life at the Museum of the Earth in Ithaca, New York.

tweet

Hey, that looks familiar! Source

The above tweet from the London Natural History Museum finally clued me in that the Lucas Triceratops had been hiding in plain sight for more than a century. The NHM (then the British Museum) received their Triceratops from the Smithsonian in 1907 (confirmed in the July 1907 issue of The Museums Journal), just when the Smithsonian had an extra Triceratops on hand. The London model is plainly not a cast of Gilmore’s 1905 mount, but it does resemble the Lucas model in most every detail, from the way the legs are posed to the exaggerated horns and frill. The only clear difference I can see is in the position of the head, which is much more elevated in the photos from the Buffalo and St. Louis expositions. However, I imagine the model would have been partially disassembled for transport. Perhaps when it was rebuilt in London the head ended up lower, whether by accident or design.

Unless there’s reason to think there were two copies of the Lucas Triceratops, I’d say the most parsimonious conclusion is that the London Triceratops is the very same model that was first displayed at the Pan-American Exhibition in 1901. Much like it’s long-time companion Dippy the Diplodocus, this Triceratops model is a century-old historic icon, one that has introduced generations upon generations of visitors to the enormity of deep time and the wonders of our prehistoric past. Inaccurate sculpture or not, it’s definitely something to preserve and to celebrate.

UPDATE: Shortly after I finished this post, @NHM_London responded to my inquiry with the following:

Hmm

Did I speak too soon? Source

I’m dubious that the NHM Triceratops is a copy of Gilmore’s 1905 version, but hey, it *is* their museum. I’ll leave this post up for now and follow up when I find out more. I love a good museum mystery!

References

Gilmore C.W. (1905).The Mounted Skeleton of Triceratops prorsus. Proceedings of the U.S. National Museum 29:1426:433-435.

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.

Howarth, E., Rowley, F.R., Ruskin Butterfield, W., and Madeley, C. (1908). The Museums Journal, Volume 7. Museums Association.

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Filed under dinosaurs, fossil mounts, history of science, marginocephalians, museums, NHM, NMNH

The Last American Dinosaurs Has Arrived!

Hatcher greets visitors

Hatcher the Triceratops greets visitors at the entrance to The Last American Dinosaurs.

Dinosaurs are once again on display at the National Museum of Natural History. Opening just in time for Thanksgiving weekend, “The Last American Dinosaurs” provides a much-needed dose of paleontology while the main fossil hall is being renovated. I was fortunate enough to take part in a preview tour for social media users – you can check out the storified version, or read on for photos and my initial thoughts on the new exhibit.

Stan is cool

Stan the T. rex is sure to be a crowd-pleaser.

Babies

Triceratops growth series reveals how much we’ve learned about the lives of dinosaurs over the last 25 years.

As promised, there are plenty of dinosaurs on view. Specifically, these are the dinosaurs of Maastrichtian North America, the last of these animals to grace this continent before the extinction event 66 million years ago. In addition to the mounted skeletons of Triceratops and Tyrannosaurus discussed in the previous post, be on the lookout for a hatchling and juvenile Triceratops, an Edmontosaurus, and bits and pieces from dromaeosaurs and pachycephalosaurs.

However, the dinosaurs are just the tip of the iceberg. As lead curator Hans-Dieter Sues explained within the first few minutes of the tour, the central message of this exhibit is that dinosaurs were only one part of a complex ecosystem. To that end, the dinosaurs of The Last American Dinosaurs are outnumbered by a menagerie of of reptiles, mammals, invertebrates, and plants that shared their world, most of which are on display for the first time. These specimens come from a variety of sources. Some, including turtles and fossil leaves, were collected by NMNH paleontologists in North Dakota specifically for this exhibit. Others, like the lizard Polyglyphanodon, have been in the museum’s collection since the 1930s but have never before been put on display. I also spotted a few casts sourced from Triebold Paleontology, including the mammal Didelphodon and the alligator-like Stangerochampsa

Gilmore specimen

This Polyglyphanodon was collected by Charles Gilmore in the 1930s.

crocs

Stangerochampsa and Champsosaurus are examples of animals that survived the K/T extinction.

Much like the Human Origins exhibit, The Last American Dinosaurs incorporates the faces of Smithsonian researchers and staff throughout the displays. There are large photos showing the museum’s scientists at work in the field, and the popular windowed FossiLab has found a new home in this exhibit. In addition, a large area is deservedly devoted to scientific illustrator Mary Parrish, chronicling the methods she uses to turn fossil data into gorgeously detailed renderings of prehistoric animals and environments. Videos of Parrish and others at work can be seen here.

I’m definitely a fan of this personalized approach to science communication. In-house scientists are museums’ most important and unique resources, and placing them front-and-center reminds visitors that science is done by real and diverse people, not caricatures in lab coats. A human face goes a long way toward making the process of doing science relateable to visitors.

new stuff

Handwritten labels on these fresh from the field fossils provide a personal touch.

The phenomenon of extinction is another important theme in The Last American Dinosaurs. The exhibit details how an asteroid impact combined with several other factors to radically alter the environment worldwide, causing 70% of species to die out (fun fact: ambient temperatures in North America directly after the impact were comparable to the inside of a brick pizza oven). However, the exhibit goes on to make direct comparisons between the K/Pg extinction event and the anthropogenic extinctions of today. Habitat destruction, introduction of invasive species, and climate change caused by burning fossil fuels are instigators of environmental upheaval as powerful as any space rock.

extinction

This moa and dodo remind visitors that extinction isn’t limited to the distant past.

In this way, The Last American Dinosaurs is a warm-up for the key messages of the new fossil hall. The overarching theme of the planned exhibit is that “Earth’s distant past is connected to the present and shapes our future.” It will showcase how living things and their environments are interdependent, and change over time. Crucially, it will also demonstrate how our understanding of how life has changed over time is important for understanding and mitigating our impact on present-day ecosystems. The Last American Dinosaurs is evidently a testing ground for how these ideas will resonate with audiences.

paleoart

Historic models of Agathaumas and Triceratops by Charles Knight and Charles Gilmore.

In designing modern paleontology exhibits, museum workers have tried many approaches to squelch the idea of the dinosaur pageant show and instead convey how the science of paleontology is relevant to our understanding of the world around us. Back in 1995, the American Museum of Natural History tried a cladistic arrangement with a focus on biodiversity. More recently, the Field Museum used the process of evolution to frame the history of life on Earth. While there are certainly overlaps with what has come before, the “modern implications of environmental change over deep time” approach under development at NMNH is fairly novel, and also quite timely. Some of the displays in The Last American Dinosaurs hit pretty close to home, and I’m eager to find out how visitors respond.

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Filed under dinosaurs, exhibits, fossil mounts, mammals, marginocephalians, museums, NMNH, ornithopods, paleoart, reptiles, reviews, science communication, theropods

Hatcher, Stan, and the Changing Identities of Fossil Mounts

Photo by the author

Hatcher the Triceratops and Stan the T. rex in the NMNH fossil hall, early 2014. Photo by the author.

Although the east wing fossil halls are closed for renovation until 2019, the National Museum of Natural History will not be without a dinosaur display for much longer. An interim exhibit entitled “The Last American Dinosaurs” will open later this month, occupying the space that formally held the “Written in Bone” exhibition. The Last American Dinosaurs will cover a small but important slice of the age of dinosaurs: the final ecosystem to grace North America before the extinction event 66 million years ago. While the new exhibit will feature several show-stealing dinosaurs, the main message is that these animals lived within a complete and complex ecosystem, just like the animals of today. The exhibit will also cover the phenomenon of extinction, and how massive environmental change (whether caused by a giant space rock or by human activity) can drastically alter the course of life on Earth.

What I’d like to discuss in this post are the two dinosaurian centerpieces of the exhibit: Hatcher the Triceratops and Stan the Tyrannosaurus. Both mounts stood in the classic fossil hall for years, and I’ve already written extensively about each of them. Nevertheless, these two dinosaurs nicely encapsulate the history of mounted fossil skeletons, as well as the changing face of museum paleontology. As the ambassadors to the Smithsonian’s dinosaur collection for the next five years, I think it’s worth revisiting their origin stories.

The First Triceratops

Hatcher in Hall of Extinct Monsters

This Triceratops stood in the NMNH fossil hall for nearly 90 years. Photo courtesy of the Smithsonian Institution Archives.

The Smithsonian Triceratops hails from what we might call the golden age of museum paleontology. Mounted dinosaur skeletons were an integral part of the rise of large urban natural history museums at the turn of the 20th century. The opening of the American western frontier revealed an unprecedented treasure trove of fossils, far greater than what was previously known in Europe. As a result, paleontology became one of the first realms of science in which Americans were leaders, and patriotism was a significant factor in the growing public enthusiasm for extinct monsters. Wealthy benefactors of recently formed institutions like the American Museum of Natural History and the Field Columbian Museum envisioned the mounted skeletons of dinosaurs as an opportunity to increase attendance and public interest, and they provided ample funding to find fossils for display. These efforts were not wasted, as the golden age fossil mounts have been enjoyed for generations…and most are still on display today.

It’s easy to get caught up in the romanticism of this era of discovery and exposition. Golden age fossil mounts were forged into being entirely in-house. At a given museum, the same small group of staff was frequently responsible for finding, preparing, describing, naming and mounting a new dinosaur. As such, fossil mounts were typically exclusives to particular museums, and they garnered significant amounts of institutional and regional pride. New York had “Brontosaurus” and Tyrannosaurus. Pittsburgh had Diplodocus. And for more than 20 years, Washington, DC had the world’s only mounted Triceratops.

Hatcher in Sunday star

A spread in the June 11, 1905 Sunday Star profiled the Smithsonian Triceratops. Image courtesy of the Smithsonian Institution Archives.

Built in 1905 by Charles Gilmore and Norman Boss, the Smithsonian Triceratops has been a Washington, DC attraction for longer than the Lincoln Memorial. Like most turn of the century dinosaur mounts, it is not a single specimen but a composite of several individuals. The fossils were recovered from Wyoming by the prolific fossil hunter John Bell Hatcher, working in the employ of O.C. Marsh and the United States Geological Survey*. USNM 4842, the most complete partial skeleton available, provided the torso and pelvis, while the remains of at least six other Triceratops filled in the rest of the mount.

*Incidentally, this means the Triceratops doesn’t quite fit the story I outlined above. It was not discovered or named by Smithsonian scientists – instead, the Smithsonian inherited the fossils Marsh collected for the federal government when he was through with them.

Even though it was a slightly disproportionate chimera, for experts and laypeople alike the Smithsonian Triceratops mount was Triceratops. Virtually every illustration of the animal for decades after the mount’s debut dutifully copied its every eccentricity, including the slightly undersized head and excessively sprawled forelimbs. If you can strain your eyes to read Sunday Star article above, it’s also interesting to see how the mount was presented to the public. Even in an era when museum displays were unapologetically created by experts for experts, the Triceratops is repeatedly likened to a fantastical monster. Although the creation of the mount was an important anatomical exercise for the small community of professional paleontologists, it seems that for most visitors a display like this primarily served as whimsical entertainment.

Hatcher_tempdisplay

Hatcher was moved to his new home on the second floor at the beginning of the summer. Photo by the author.

After a brief stint in the original United States National Museum (now called the Arts and Industries Building), Gilmore and Boss’s Triceratops was transferred the east wing of the present-day NMNH in 1911. It remained there for 90 years, until the aging and deteriorating fossils were finally disassembled and retired to the collections. In their place, Smithsonian staff created an updated replica skeleton, called “Hatcher”, from digital scans of the original bones. This version is the Triceratops that will be on display in The Last American Dinosaurs.

A Prefab Tyrannosaurus?

Stan. Photo by Chip Clark.

Stan the T. rex, as seen in the classic NMNH fossil hall. Photo by Chip Clark.

Since 2000, Hatcher the Triceratops was in a permanent face-off with another replica mount, Stan the Tyrannosaurus. Unlike Hatcher, Stan is not based on fossils in the Smithsonian collection. This T. rex cast was purchased from the Black Hills Institute, a private company that  produces and sells replica fossil skeletons (as well as original specimens, which is another issue entirely). Discovered by avocational fossil hunter Stan Sacrison in 1987, Stan the dinosaur was excavated and is now owned by BHI. Since 1995, BHI has sold dozens of Stan replicas to museums and other venues. The Smithsonian acquired its version in 1999, in part because of visitor demand for the world’s most famous dinosaur, but also apparently as a consolation prize for missing out on Sue.

Clearly, much has changed in the way museums source their dinosaurs. Rather than creating fossil mounts on-site, museums frequently contract out the production to exhibit fabrication companies like Research Casting International, Gaston Design, and the aforementioned Black Hills Institute. These companies can construct mounts using fossils or casts from a particular museum’s collection, but they also offer catalogs of made-to-order skeletons. Thanks to these exhibit companies, more or less identical copies of certain dinosaurs are now on display all over the world.  In Stan’s case, the Smithsonian version has a twin just seven miles north at the Discovery Communications building in Silver Spring.

Stan can be set up in a under an hour. This version was recently displayed at Farmington Museum.

Stan replicas can be set up in a under an hour. This version was recently displayed at New Mexico’s Farmington Museum. Source

An argument could be made that this degree of replication lessens the impact and cultural value of dinosaur displays. How much allure does a mount have when identical versions can be seen at dozens of other locations, including corporate offices and amusement parks? I would counter that this is a small price to pay when we consider the substantial educational benefits of this unprecedented availability of dinosaur skeletons. Widespread casts like Stan give people all over the world the opportunity to see a T. rex in person, an experience that was until recently limited to those with the means to travel to a handful of large cities. Typically priced in the tens of thousands of dollars, dinosaur casts certainly aren’t cheap, but they are still within the means of many small to mid-sized local museums.

Furthermore, these casts are hardly rolling off of assembly lines. They are exact replicas of real fossils, and require a tremendous amount of experience and skill to produce. Mounts are manufactured as needed, and are customized to meet the needs of the specific museum. Meanwhile, museums still employ scientists who collect new fossils for their collections. The difference is that these collecting trips usually seek to answer specific research questions, rather than going after only the biggest and most impressive display specimens. Finally, museums definitely haven’t outsourced exhibit production entirely. All summer at NMNH, in-house preparators have been working in collaboration with contractors from Research Casting International to dismantle the historic fossil exhibits in preparation for the upcoming renovation.

Reassembling Stan upstairs. Photo by Abby Telfer.

Reassembling Stan for The Last American Dinosaurs. Photo by Abby Telfer.

There’s one more change for the better in modern paleontology exhibits. When the Smithsonian Triceratops was first introduced to the world in 1905, natural history displays tended to focus on the breadth of collections. Curators composed exhibits with other experts in mind, and the non-scholars that actually made up the majority of museum visitors were not directly catered to. Without any context to work with, fossil mounts were little more than toothy spectacles for most visitors. Today, museum staff create exhibits that tell stories. The Last American Dinosaurs has been explicitly designed to contextualize the dinosaurs – to show how they fit into the history of life on Earth, and why their world is meaningful today. How successful will this be? I’ll report back after the exhibit opens on November 25th.

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Filed under dinosaurs, exhibits, fossil mounts, history of science, marginocephalians, museums, NMNH, reptiles, theropods

Museums and the Triceratops Posture Problem – Part 2

Triceratops at the National Museum of Natural History.

Triceratops “Hatcher” at the National Museum of Natural History. Photo by the author.

Back in July, I wrote about how the forelimb posture of ceratopsian dinosaurs like Triceratops has puzzled paleontologists for more than a century. Most quadrupedal dinosaurs held their front legs straight under their bodies, and it would make sense if Triceratops and its kin did the same. However, when researchers attempted to physically articulate skeletons for museum displays, they found that that the humerus would only fit properly with the scapula if it projected horizontally from the torso – like the sprawling limbs of a lizard. Over the years, new specimens, new research methods, and new technologies have all been used to help resolve this conundrum, but a consensus has not yet been reached. Of particular interest to me is the unusually central role mounted skeletons in museums have played in this biomechanical mystery. The previous post covered the historic Triceratops mounts; this entry will take a look at some more recent Triceratops displays in American museums.

The Hatcher Project

In 1998, a visitor looking at the Triceratops mount at the National Museum of Natural History happened to sneeze. To her alarm, the sneeze was enough to knock a small fragment of bone off the pelvis and onto the floor. The visitor thoughtfully informed security, and after a thorough conservation assessment by Kathy Hawks, it was determined that the 93-year-old mount needed to come off exhibit, and soon. The delicate fossils had served valiantly through 23 presidential administrations, but now it was time for the skeleton to be disassembled and preserved for posterity.

Retiring the classic Triceratops gave Ralph Chapman, head of the Museum’s Applied Morphometrics Laboratory, an opportunity to take on a project he had been germinating for some time. Chapman wanted to demonstrate the potential of 3-D scanning technology for paleontology research by creating a high-resolution digital duplicate of a dinosaur skeleton. Today, the process of making and studying digital copies of fossils is both widespread  and remarkably straightforward, but in the late 1990s it was practically science fiction. Nevertheless, the historic Triceratops was an ideal digitization candidate for several reasons. First, the digital assets would reduce handling of the delicate and aging original fossils. Second, exact copies of the scanned bones could be made from milled foam and plastics to create a replacement exhibit mount. Finally, a digital Triceratops would be a great opportunity to revisit the ceratopsid posture problem in a new way.

digital hatcher

A rendering of the digital Hatcher. Source

The ensuing Hatcher Project (the Triceratops was named in honor of John Bell Hatcher, who found the original fossils in the late 19th century) was a collaboration between Museum staff and several industry experts, including Lisa Federici of Scansite 3-D Services and Arthur Andersen of Virtual Surfaces, Inc. The first step was to place stickers on 100 key points on the Triceratops. These points were recorded with a surface scanner, so that the historic mount could be digitally recreated in its original pose. After that, fossil preparators Steve Jabo and Pete Kroehler carefully dismantled the skeleton. Each bone from the skeleton’s right side* was then scanned individually, producing 20 gigabytes of data (you’re supposed to gasp…again, this was the late 90s).

*Bones from the right side were mirrored to reproduce the left half of the skeleton. 

Since the original mount had been a somewhat disproportionate composite, the team made a few changes when building the new digital Hatcher. Some elements, including the undersized skull, were enlarged to match the rest of the skeleton. In addition, parts that had either been sculpted or were not actually Triceratops bones – such as the dorsal vertebrae and the hindfeet – were replaced with casts acquired from other museums. The result was the world’s first complete digital dinosaur, and shortly afterward, the first full-sized replica skeleton generated from digital assets.

Updated "Hatcher" mount's rarely seen right side. Source

Hatcher’s seldom seen right side was briefly exposed recently, before the mount was moved to a temporary second floor location. Source

In April 2000, the Hatcher team convened at NMNH to determine how the new replica mount would be posed. Chapman, Jabo, and Kroehler were joined by Kent Stevens of the University of Oregon, Brenda Chinnery of Johns Hopkins University, and Rolf Johnson of the Milwaukee Public Museum (among others) to spend a day working with a 1/6th scale model produced by stereolithography specialist Jason Dickman. The miniature Hatcher allowed the researchers to physically test the skeleton’s range of motion without the difficulty of manipulating heavy fossils.

The day was full of surprises. The team was impressed by the wide range of motion afforded by the ball and socket joint connecting the Triceratops skull to the atlas. They also found that the elbow joints could lock, which may have been helpful for shock absorption when the animal smashed things with its face. Nevertheless, when it came time to articulate the humerus and scapula, the team essentially validated Charles Gilmore’s original conclusion that sprawling forelimbs worked best (although the new Hatcher mount stands a little straighter than the historic version, and a lot straighter than the New York Triceratops). While other paleontologists had used indirect evidence (like evenly spaced trackways and wide nasal cavities for sucking down lots of oxygen) to support the idea that Triceratops was a straight-legged, fast-moving rhino analogue, articulating the actual bones showed once again that ceratopsid forelimbs had to sprawl.

Houston and Los Angeles Mounts

LACM Triceratops mount. Photo by Heinrich Mallison, many more here.

LACM Triceratops mount. Photo by Heinrich Mallison, many more here.

Hatcher is the Triceratops I am best acquainted with, and I can’t help but think of it as the definitive example of this animal. However, two new Triceratops mounts demonstrate a radically different take on ceratopsid posture. In 2011, the Natural History Museum of Los Angeles County completed a thoroughly renovated dinosaur hall, which features a brand-new Triceratops mount at its entrance. Like Hatcher, this skeleton is a composite of several specimens, in this case excavated in Montana by LACM teams between 2002 and 2004. Phil Fraley Productions, the exhibit fabrication company behind Sue and the Carnegie Museum dinosaurs, was responsible for mounting the fossils. The primary specimen (LACM 141459, which provided the skull and right forelimb) is notable because it included a completely intact and articulated front leg. Although the analysis of this important find has yet to be published, exhibit curator Luis Chiappe tellingly chose an erect, rather than sprawling, forelimb posture.

Meanwhile, the Houston Museum of Nature and Science opened its colossal, 30,000 square foot Hall of Paleontology in 2012. Among the dozens of mounted skeletons on display is Lane, reportedly the most complete Triceratops ever found. The museum purchased the skeleton from the Black Hills Institute, and the company also constructed the display mount. Robert Bakker, who curates the Hall of Paleontology, specifically requested that Lane be given a straight-legged, trotting pose. With two legs off the ground, this display emanates strength and speed.

"Lane" at Houston Museum

“Lane” at Houston Museum of Nature and Science. Source

So how did the Los Angeles and Houston exhibit teams manage to construct plausible-looking, straight-legged Triceratops mounts? Since full descriptions of either specimen have not been published, it’s hard to say for sure. From the look of it, however, the new mounts both have narrower, flatter rib cages (as suggested by Paul and Christiansen), which allows more room for the elbow. Likewise, the shoulder girdles are lower than Hatcher’s, and they seem to have been rotated closer to the front of the chest. Also note that the forelimbs of the Los Angeles and Houston mounts are not completely erect – they are strongly flexed at the elbow, as is typical of many quadrupedal mammals.

These new mounts don’t mean the Triceratops posture problem is resolved, though. The angle of the ribs and the position of the scapula are apparently both touchy subjects, so alternate interpretations are sure to arise in the future. After all, Triceratops forelimb posture isn’t just an esoteric bit of anatomical trivia: it has major implications for the speed and athleticism of an extremely successful keystone herbivore. Understanding the limitations on this animal’s movement and behavior can contribute to our understanding of the ecosystem and environmental pressures in late Cretaceous North America. As such, I am eagerly awaiting the next round in this 100-plus year investigation.

A big thank you to Rebecca Hunt-Foster and Ralph Chapman for sharing their time and expertise while I was writing this post!

References

Chapman, R. Personal communication.

Chapman, R., Andersen, A., Breithaupt, B.H. and Matthews, N.A. 2012. Technology and the Study of Dinosaurs. The Complete Dinosaur, 2nd Edition. Bloomington, IN: Indiana University Press.

Fujiwara, S. and Hutchinson, J.R. 2012. Elbow Joint Adductor Movement Arm as an Indicator of Forelimb Posture in Extinct Quadrupedal Tetrapods. Proceedings of the Royal Society 279: 2561-2570.

Hunt-Foster, R. Personal communication.

Paul, G.S. and Christiansen, P. 2000. Forelimb Posture in Neoceratopsian Dinosaurs: Implications for Gait and Locomotion. Paleobiology 26:3:450-465.

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Filed under anatomy, dinosaurs, fossil mounts, history of science, marginocephalians, museums, NMNH, reptiles

Museums and the Triceratops Posture Problem – Part 1

The Triceratops in the Hall of Extinct Monsters, circa 1911. Photo from NMNH on flickr.

The world’s first Triceratops mount at the United States National Museum, built in 1905. Photo courtesy of the Smithsonian Institution Archives.

We know more about dinosaurs today than previous generations of researchers would have ever thought possible. Who would have guessed that in the 21st century, we would have direct evidence for the color of some species, or a detailed understanding of the life history and ontogeny of others? Modern paleontologists can delve deeper into the biology and ecology of extinct animals than ever before, so it comes as a surprise when a very basic question about dinosaur physiology has gone without a definitive answer for well over a century.

For 125 years, paleontogists have struggled to understand how large ceratopsids like Triceratops held their forelimbs. Usually, someone with a good understanding of anatomy can assemble a tetrapod skeleton without much difficulty. Vertebrates are all built along the same basic body plan, and bones fit together in the same general way. However, the forelimb bones of Triceratops and its relatives are quite perplexing. The head of the humerus, which articulates with the scapula, is off-center and extends backward from the shaft. Meanwhile, the lesser tubercle, a tiny nubbin on a human humerus, is enormous and boxy. Taken together, these two traits make it so that if Triceratops held its arm erect and under its body, like most dinosaurs did, the humerus would either puncture the rib cage or be completely dislocated from the shoulder. The simplest way to solve this is to orient the humerus so that the arms project at right angles from the torso, like the sprawling limbs of a lizard. But this just looks wrong. First, ceratopsid hindlimbs are plainly meant to stand straight up. Sprawling forelimbs make Triceratops look mismatched, like the front end a tortoise sewn was to the back end of a rhino. Second, and perhaps more importantly, a sprawling posture would drastically inhibit speed and maneuverability in what is otherwise a very powerfully-built animal. The posture of Triceratops and its kin would ultimately have had a dramatic impact on the animal’s behavior, lifestyle, and ecological role.

Paleontologists haven’t spent the last century just scratching their heads over this problem. Ceratopsid forelimbs have inspired a considerable amount of research over the years, as scientists continue to develop new methods and new tools to explore the biomechanics of prehistoric animals. New technologies have been developed and refined specifically to help determine how Triceratops and its relatives walked and stood. Nevertheless, my intent with this post is not to thoroughly recount the history of ceratopsid forelimb research (if you’re interested, most of the articles referenced below are freely available online). Instead, I’d like to explore the central role museum displays have played in this debate. An artist drawing a two-dimensional image of Triceratops can fudge the orientation of the limbs (and many have), but the team building a mounted skeleton needs to know exactly how to articulate the bones. The ceratopsid posture question first arose in the process of building a mounted Triceratops skeleton for display, and museum mounts continue to be referenced by researchers looking to “ground truth” their ideas. While museum mounts usually exist primarily for education and display, in the case of the ceratopsid forelimb question these exhibits have long been central to the process of studying fossil evidence and creating knowledge.

Early Reconstructions

Marsh's 1891 restoration of Triceratops.

Marsh’s 1888 restoration of Triceratops.

O.C. Marsh published the first illustrated reconstruction of a Triceratops skeleton in 1888. Marsh was legendary in his attention to detail, and the restoration holds up reasonably well today – better, in fact, than his illustrations of Stegosaurus and “Brontosaurus.” Contemporary scientists had no complaints, even though Marsh had given the Triceratops vertical forelimbs. Other dinosaurs had erect limbs, as does the superficially similar modern rhino, so why shouldn’t Triceratops? Marsh’s reconstruction was brought to three-dimensional life in 1901, when the Smithsonian Institution commissioned a life-sized papier mache replica of a Triceratops skeleton for the Pan-American Exposition in Buffalo. Since the model was hand-sculpted, not casted from original fossils, artist F.A. Lucas had no trouble making Triceratops stand up straight, exactly as portrayed by Marsh. The model appeared again at a Smithsonian exhibit in St. Louis, but was apparently lost or destroyed shortly afterwards. In its place, newly hired United States National Museum preparator Charles Gilmore began work on a mounted Triceratops skeleton composed of original fossils.

St. Louis Expo

Straight-legged Triceratops model at the Pan American Expo in St. Louis. Source

Gilmore’s 1905 Triceratops mount was the first real skeleton of a ceratopsid ever assembled for display (first image). Like virtually all dinosaur mounts of the era, the skeleton was a composite of several specimens and a few sculpted pieces. All the Triceratops fossils at Gilmore’s disposal were collected by John Bell Hatcher in the late 19th century, and inherited by the Smithsonian as part of the Marsh collection. USNM 4842, a partial skeleton consisting mostly of a torso and pelvis, formed the basis for the mount, but at least six other individuals were also incorporated. Gilmore selected the skull because it was more complete and less distorted than the other Triceratops skulls available, but it was also on the small side compared to the body. Likewise, the left humerus was about 40% smaller than the right, and conspicuously three-toed Edmontosaurus hindfeet were used (no Triceratops feet had been found at the time). In the process of building his Triceratops, Gilmore had to make several changes to the idealized Triceratops envisioned by Marsh, most notably the orientation of the forelimbs. Not only was it apparently impossible to articulate the humerus in an upright position, but as Gilmore explained it, “a straightened form of leg would so elevate the anterior portion of the body as to have made it a physical impossibility for the animal to reach the ground with its head.”

The American Museum of Natural History produced their own Triceratops mount in 1923. Like its USNM predecessor, the AMNH Triceratops was a composite of several specimens. AMNH 5033, discovered by Barnum Brown in Montana and consisting of most of the dorsal vertebral column, ribs, and pelvic girdle, made up the largest portion of the mount. The skull was recovered by Charles Sternberg in Wyoming, and many of the appendicular bones were sculpted or cast from Smithsonian specimens. Preparator Charles Lang spent over 263 working days on the project, and much of that time was reportedly spent puzzling over the forelimbs. Lang studied living and preserved specimens of a variety of tetrapods, including rhinos, lizards, crocodiles, and tortoises, trying to find a living analogue for the strangely shaped ceratopsid bones. He ended up articulating the forelimbs so that they were even more widely splayed than Gilmore’s reconstruction, to the point that the back of the Triceratops slopes dramatically forward, and the head is almost dragging along the ground. In an accompanying paper, Henry Osborn asserted that “nothing short of a horizontal humerus and completely everted elbow would permit proper articulation of the facets.” By way of explanation, Osborn offered that this posture might have been helpful in withstanding a frontal impact.

triceratops

American Museum of Natural History Triceratops mount, circa 1959. Photo courtesy of the AMNH Research Library.

Together, the Washington and New York Triceratops mounts, with their mismatched tortoise-in-the-front, rhino-in-the-back posture, would come to define both popular and scientific conceptions of ceratopsids for the better part of a century. Other museums followed Gilmore and Lang’s lead and built sprawling ceratopsids of their own, including Richard Lull’s 1929 Centrosaurus at the Peabody Museum of Natural History and Kenneth Carpenter’s 1986 Chasmosaurus at the Academy of Natural Sciences. Even as recently as 1995, AMNH curators chose not to change a single bone on the historic Triceratops mount while modernizing their exhibit.

Voices of Dissent

Robert Bakker was one of the first to challenge the ceratopsid forelimb orthodoxy. In 1986, Bakker criticized Gilmore and Lull’s museum mounts and resurrected Marsh’s original interpretation of a straight-legged Triceratops. His reasoning was that the ceratopsid glenoid fossa (the concavity on the scapula that holds the head of the humerus) was more like the narrow cup of a horse or rhino than the wide trough of a lizard. Bakker went as far as to suggest that Triceratops and its kin might have been able to run or even gallop. Gregory Paul and others piled on, arguing that earlier researchers had run into trouble articulating Triceratops forelimbs because they had made the ribcage too broad. If the ribs were articulated so that the animal had flat flanks, the elbow apparently wouldn’t get in the way. Additional evidence for an upright stance came from a set of ceratopsid trackways described by Martin Lockley and Adrian Hunt. The trackways showed forefeet in line with the hindfeet, suggesting that front and back legs were not mismatched, after all.

This cast of the AMNH Triceratops at the Field Museum replicates the sprawling posture. Photo by the author.

This cast of the AMNH Triceratops at the Field Museum replicates the sprawling posture of the original. Photo by the author.

However, paleontologists like Peter Dodson were unmoved by these new arguments. Dodson proposed that the trackways had been misinterpreted: since ceratopsids are wider at the hips than at the shoulders, evenly spaced front and back prints should imply that the animal was holding its forelimbs out farther than its hindlimbs. Dodson was concerned that the rhino analogy was being taken too far: Triceratops looked like a rhino, so reasearchers were trying their hardest to make it move and behave like a rhino.

As Kenneth Carpenter explained in a comment last year, dinosaurs can do anything on paper, but physically assembling a skeleton forces you to confront the reality of what the bones can and cannot do. In the last decade, two new Triceratops mounts provided paleontologists the opportunity to re-explore this process, with more complete specimens and modern technology at their disposal. Next time, we’ll take a look at what the new Triceratops displays at the National Museum of Natural History and the Los Angeles County Natural History Museum can tell us about ceratopsid posture and lifestyle.

References

Bakker, R.T. 1986. The Dinosaur Heresies: New Theories Unlocking the Mystery of Dinosaurs and Their Extinction. New York, NY: Citadel Press.

Dodson, P. 1996. The Horned Dinosaurs: A Natural History. Princeton, NJ: Princeton University Press.

Fujiwara, S. 2009. A Reevaluation of the Manus Structure in Triceratops (Ceratopsia: Ceratopsidae). Journal of Vertebrate Paleontology 29:4:1136-1147.

Fujiwara, S. and Hutchinson, J.R. 2012. Elbow Joint Adductor Movement Arm as an Indicator of Forelimb Posture in Extinct Quadrupedal Tetrapods. Proceedings of the Royal Society 279: 2561-2570.

Gilmore C.W. 1905.The Mounted Skeleton of Triceratops prorsus. Proceedings of the U.S. National Museum 29:1426:433-435.

Makovicky, P. 2012. Marginocephalia. The Complete Dinosaur, 2nd Edition. Eds. Brett-Surman, M.K., Holtz, T.R. and Farlow, J.O. Bloomington, IN: Indiana University Press.

Osborn, H.F. 1933. Mounted Skeleton of Triceratops elatus. American Museum Novitates 654:1-14.

Paul, G.S. and Christiansen, P. 2000. Forelimb Posture in Neoceratopsian Dinosaurs: Implications for Gait and Locomotion. Paleobiology 26:3:450-465.

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Filed under AMNH, anatomy, dinosaurs, fossil mounts, history of science, marginocephalians, museums, NMNH, reptiles