Category Archives: theropods

Building Gorgeous George

The Field Museum has shared this fascinating raw footage of the assembly and installation of Gorgeous George the Daspletosaurus (formerly Gorgosaurus and Albertosaurus). It is made available under a  Attribution-Noncommercial-No Derivative Works 3.0 license.

The fossils in question were discovered by Barnum Brown in 1914 during an American Museum of Natural History expedition to Alberta. It was the largest but least complete of several (presumed) Gorgosaurus skeletons collected by Brown, and only the skull was ever displayed in New York. In 1955, Field Museum trustee Louis Ware bought the fossils, an event heralded in the members’ newsletter as “the most important acquisition to the museum in recent years.” Preparator Orville Gilpin assembled the skeleton with the help of Stanley Kukzek, Cameron Gifford, and William Turnbull. Gorgeous George debuted in the Field Museum’s central Stanley Field Hall in March 1956, alongside a scale model created by staff artist Maide Weibe.

The similarities to modern mounting techniques on display in the video are more striking than the differences. From ratchets to chain hoists, the tools used by Gilpin and his colleagues appear quite similar to those used for this sort of work today. I suppose the lab coat-over-slacks look has gone out of style, though.

Gorgeous Gorge in its updated poses, as it is exhibited today. Photo by the author.

Gorgeous George remained in place until 1990, when it was relocated and remounted as part of the Life Over Time exhibition. While the updated Daspletosaurus trades the old Godzilla pose for a more accurate horizontal posture, it does not include the original skull (as Gilpin’s version did). The real skull is now on display at the Museum’s east entrance, however.

On the subject of Gorgeous George, check out Emily Graslie’s Brain Scoop video on paleoart at the Field Museum, which includes a not-to-be-missed dramatic reading of a poem by Curator Eugene Richardson!

References

Chicago Natural History Museum Bulletin. (March 1956). 27:3.

Gilpin, O.L. (1959). A Freestanding Mount of Gorgosaurus. Curator 2:2:162-168.

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Filed under dinosaurs, exhibits, FMNH, fossil mounts, museums, theropods

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

Tyler Keillor’s new tyrannosaurs

Paleoartist Tyler Keillor has not one but two new tyrannosaur sculptures on display in museums north of Chicago, and this past weekend I paid both of them a visit. Keillor has been reconstructing extinct animals since 2001, most frequently in collaboration with Paul Sereno. You may well have seen Keillor’s fleshed models of Rugops, Kaprosuchus, Eodromaeus, and others, all commissioned by Sereno to accompany press releases announcing new discoveries. Keillor also specializes in restoring incomplete fossil material, assembling physical or digital models of the complete, undamaged bones. The composite Spinosaurus skeleton from the 2014 National Geographic traveling exhibit was his work, as is the skull on the mounted skeleton of Jane the juvenile Tyrannosaurus at the Burpee Museum of Natural History.

Tyler Keillor’s Dryptosaurus at the Bess Bower Dunn Museum.

One of Keillor’s latest and most ambitious pieces debuted on March  24th at the brand-new Bess Bower Dunn Museum in Libertyville, Illinois. Standing at the entrance to the museum’s galleries, the life-sized Dryptosaurus is a show-stopping centerpiece. Never mind that no dinosaur fossils have been found in Illinois –  Dryptosaurus lived on the other side of the Cretaceous continent of Appalachia, which is as good an excuse as any to include a giant model dinosaur.

During the very well-attended opening event, Keillor gave a standing-room-only talk about creating the model. Dryptosaurus is only known from a handful of fossils, the most complete parts being the arm and leg. Working with Richard Kissel, who served as the project’s scientific advisor, Keillor had to make a number of educated choices to turn the available fossil material into a 20-foot fleshed model. The shape of the head, for example, is based on that of Jane, while the tiny, millimeter-sized scales are informed by recently published skin impressions of various tyrannosaurs. Less certain is the choice to give Dryptosaurus a two-fingered hand. For the time being, the three-fingered skeletons Research Casting International built for the New Jersey State Museum are no less reasonable.

Opening day at the Dunn Museum was mobbed – it’s great to see so many people excited about a new museum!

Keillor’s 2009 Dryptosaurus head is meant to be a male, while the new sculpture represents a female.

During the planning stages, Keillor prepared three possible poses for the museum to pick from. The Dryptosaurus could be standing tall, leaning forward with its mouth open, or crouching down next to a nest mound. Keillor favored the nesting pose, both because it was unusual and because the Dryptosaurus holotype fossils may have come from an animal that had recently laid eggs*. Unsurprisingly, museum staff opted for the more spectacular open-mouthed version.

The bulk of the model is foam, created on a milling machine using data from a digital model produced by Keillor. The foam body form is covered with nearly 200 pounds of epoxy putty, applied and textured by hand. Keillor casted the head as a separate piece, using the molds from a standalone Dryptosaurus head he produced for the Dunn Museum’s predecessor in 2009. The patches of fluff are made from a commercially-available synthetic fiber that resembles kiwi feathers.

*Edward Cope noted in the 1880s that the Dryptosaurus limb bones had large, hollow medullary cavities. Gravid female birds grow extra layers of bone in their medullary cavities to stockpile calcium, which they use to produce eggshells. We now know that several non-avian dinosaur species did the same. 

Little Clint at the Dinosaur Discovery Museum.

Keillor’s other new model is “Little Clint” the infant Tyrannosaurus rex, which debuted at the Dinosaur Discovery Museum in Kenosha, Wisconsin with absolutely no fanfare. The model is part of a new exhibit all about the discovery and interpretation of the pocket-sized T. rex fossils it’s based on. Frustratingly, there’s no mention of the exhibit on the museum’s website, and I would have never known about it if Keillor hadn’t mentioned it (I’m sure it’s not the museum’s fault, I too have known the joys of working within the constraints of a large municipal website). The model is roughly two and a half feet long, and is almost grotesque in its spindly proportions. Judging by photos accompanying the model, Keillor used a traditional build-up process, rather than the physical-digital hybrid techniques employed in the making of the Dryptosaurus.

Dryptosaurus and Tyrannosaurus both belong to the same group of theropod dinosaurs (tyrannosaurs), but in creating the two models Keillor went in two very different directions when reconstructing their soft tissues. Working with Richard Kissel of the Yale Peabody Museum, Keillor gave Dryptosaurus a patchy coat of shaggy integument, as well as fleshy lips that would easily cover the animal’s teeth if it were to ever close its mouth. However, Carthage College’s Thomas Carr, scientific advisor for Little Clint, requested a scaly hide with a crocodilian tooth-exposing grin.

Little Clint’s toothy grin.

It turns out feathers and lips on large theropods (and tyrannosaurs in particular) are fairly contentious subjects, at least among the sort of people who like to argue about these things on the internet. It is well-established that feathery integument was widespread among theropods, and even certain other dinosaurs. Several members of the tyrannosaur family have been found with fossilized fuzz impressions, including the Dryptosaurus-sized Yutyrannus. This means it’s reasonable to expect that all tyrannosaurs, including Tyrannosaurus rex, were feathered to some degree. However, a recent publication by Phil Bell and colleagues suggests the opposite: an assortment of small skin impressions from Tyrannosaurus and its closest relatives reveal only scaly skin. Meanwhile, ongoing research by Robert Reisz demonstrates that theropods had fleshy lips, but this is contradicted by Carr’s own findings that some tyrannosaurs had armored scales on their maxillary margins.

So which interpretation of tyrannosaur soft tissue is right? For now, there is compelling evidence for both interpretations. Perhaps more fossils or new analytical techniques will eventually steer the consensus in one direction or the other. Or maybe we will never know for sure what the faces of Dryptosaurus and Tyrannosaurus looked like. For now, Keillor’s models make fascinating companion pieces. They are windows into two possible versions of the deep past, reminding us to accept a little ambiguity now and then.

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Filed under dinosaurs, exhibits, museums, paleoart, theropods

Bath Time for Sue

I moved to the Chicago area a couple months ago, and yesterday I witnessed a very important event that only happens twice a year. I am referring, of course, to Field Museum Collections Manager Bill Simpson dusting the mounted skeleton of Sue the Tyrannosaurus rex.

It’s unusual for a collections manager to personally perform this sort of basic maintenance at an institution the size of the Field Museum, but Simpson makes an exception for Sue. He has been in charge of the dinosaur’s well-being since the half-prepared fossils arrived in Chicago in October 1997, and has been cleaning the mounted skeleton twice a year since it was unveiled in 2000. The cleaning schedule is a compromise between the exhibits and geology departments. Exhibits would have Sue polished up more often, but the collections staff advise that the delicate fossils be touched as infrequently as possible.

Simpson blows dust off of Sue with a portable vacuum.

The cleaning process took about 90 minutes. Simpson accessed the mount by way of a scissor lift, about six feet off the floor. With the help of two assistants (one to man the lift and one to keep track of an extension cord), he used a portable vacuum to blow air on the fossils, unsettling any dust that had accumulated. Notably, Simpson took care not to bring the vacuum within twelve inches of the specimen, and never touched the fossils directly. After repeating this process eight or nine times from different vantage points around the mount, Simpson exited the lift and climbed onto the platform, going after some of the harder-to-reach crevices with a feather duster.

Truth be told, the process isn’t that interesting. I was a little embarrassed to stand around watching for as long as I did. Like most things with Sue, T. rex cleaning day is an example of really good marketing on the part of the Field Museum. Dusting is pretty standard upkeep, and I’m aware of no other museum that puts it on their public calendar. But for the fossil the world knows by name, even this basic maintenance is newsworthy. Indeed, Sue’s semiannual dusting seems to generate a major news story almost every year.

Sue’s ribs get a gentle dusting.

As the most complete Tyrannosaurus yet found and the onetime subject of an ugly four-way legal battle, Sue has been been famous since its discovery in 1990. The Field Museum won the specimen at auction in October 1997 and has been leveraging its star power ever since. A frenzy of reporters greeted the truck delivering Sue to Chicago a few days after the auction. Millions of visitors watched the fossils being prepared in a windowed lab at the Field Museum and a satellite facility at Disney World in Orlando. A naming contest (for a time, it appeared that the name “Sue” might not be legally available) generated an overwhelming 6,000 entries. And when the mounted skeleton was finally unveiled on May 17, 2000, 10,000 visitors came to see Sue in a single day. The week-long press junket saw visits from Bill Clinton and Steven Spielberg, and the Field Museum’s annual attendance soared that year from 1.6 to 2.4 million.

Sue remains a media magnet to this day. Headlines about the dinosaur are common, even outside of Chicago, and the Field Museum’s increasingly avant garde @SuetheTrex twitter account has 30,000 followers and counting. Sue has been the subject of more than 50 technical papers, several books, and hundreds of popular articles. When the Field Museum’s corporate partners paid seven figures for Sue, they weren’t just buying the museum a display specimen, they were creating an icon. Sue is a blockbuster attraction that brings visitors in the door, and the dinosaur’s name and likeness is continuously marketed for additional earned income. For example, there are now two different Sue-themed beers available!

Why isn’t Akeley elephant cleaning day a thing?

As I’ve discussed before, fossil mounts occupy a tenuous middle ground between conflicting identities. These composites of rock and plaster and steel are at once scientific specimens, works of art, and cultural touchstones. Sue takes this contradiction to previously unseen levels. On one hand, Sue the specimen is the subject of more scientific papers than any other Tyrannosaurus, and has contributed enormously to our understanding of dinosaur life history, histology, and pathology. On the other hand, Sue is a towering icon seen by 25 million Field Museum visitors of all ages. Its likeness appears on shirts, snow globes, and the aforementioned beer. And on the third hand, the Sue twitter account is, at this very moment, posting pictures of Jeff Goldblum for some reason. And that’s not even getting into Sue’s pre-Field Museum identities. Depending on who you ask, Sue could be the one that got away, a close call, a symbol of government overreach, or a harbinger of the fossil poaching crisis.

As former Field Museum president John McCarter put it, “we do dinosaurs…so that we can do fish.” Natural history museums hold immense collections in the public trust that record the world’s biodiversity. This task is neither simple nor cheap. Leveraging star attractions like Sue generates income and perhaps equally important, public interest and goodwill, which makes the less overtly captivating functions of the museum possible. The Field Museum has a great thing going with Sue, and I’m all for pushing it even further. Vials of Sue dust bunnies in the gift shop, anyone?

References

Fiffer, S. 2000. Tyrannosaurus Sue: The Extraordinary Saga of the Largest, Most Fought Over T. rex ever Found. New York, NY: W.H. Freeman and Company.

Grande, L. 2017. Curators: Behind the Scenes of Natural History Museums. Chicago, IL: University of Chicago Press.

Lee, B.M. 2005. The Business of Dinosaurs: The Chicago Field Museum’s Nonprofit Enterprise. Unpublished thesis, George Washington University.

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Filed under dinosaurs, FMNH, fossil mounts, museums, theropods

The Field Museum Shuffles its Dinosaurs

Rendering of Patagotitan and the Sue remount. Source

This morning, The Field Museum of Natural History announced two big changes to its dinosaur exhibits. First, the indispensable Sue the Tyrannosaurus will move from its prime location in the central Stanley Field Hall and into Evolving Planet, the museum’s permanent paleontology exhibit. Next, a cast of the South American sauropod Patagotitan will take Sue’s place in the main hall. Sue will be disassembled just a few months from now in February 2018. Patagotitan will be installed later next year, and Sue’s new home on the second floor opens in Spring 2019 (perhaps deliberately, this is within weeks of the National Fossil Hall’s reopening at the Smithsonian).

Sue has been the Field Museum’s defining attraction since the skeleton was acquired in 1997. It is the most complete Tyrannosaurus yet found, but it is also more than a natural history specimen. Sue is part of the pantheon of Chicago landmarks, and the public’s association of the mount with the city it resides in has all but eclipsed the legal battle that preceeded it’s acquisition.

The current Sue mount has a touch of “grenade-swallowing syndrome.” Photo by the author.

Nevertheless, the Sue mount that has been on display for 17 years is not perfect. Assembled by Phil Fraley Productions, the mount has been the subject of grumbling among tyrannosaur specialists for years: the coracoids are too far apart, the furcula is incorrectly placed, the posterior ribs are unnaturally bowed out, and so forth. Happily, Sue will be getting thoroughly updated during the move. In addition to correcting the various anatomical problems, the new mount will reintroduce Sue to its gastralia (belly ribs), which have been displayed separately since 2000, and change her crouching pose to a standing one. As Collections Manager Bill Simpson explains in the announcement video, “we now know more about how a T. rex skeleton should look and Sue is going to reflect those changes.”

Sue 2.0 will take over the second floor space occupied by the recently shuttered 3-D theater. Accessible as an annex to the dinosaur section of Evolving Planet, the Sue exhibit will contextualize the Tyrannosaurus with other fossils from the Hell Creek Formation.

Rendering of Patagotitan in the Stanley Field Hall. Source

Patagotitan is the same animal that the American Museum of Natural History billed as “the titanosaur” two years ago. Argentina’s newest megasauropod was first announced in 2014 but was formally named and published by José Carballido and colleagues just three weeks ago. While not technically the biggest known sauropod, Patagotitan is the only dinosaur in its class known  from reasonably complete remains. The skeleton itself will be more or less identical to the cast Research Casting International produced for AMNH. However, instead of being crammed into a small room, this Patagotitan will have space to stretch out, its neck craning to look over the second story mezzanine. The Field Museum exhibits team also wants visitors to be able to walk under and even touch the cast skeleton.

What do I think about all this (asked nobody)? I’m thrilled with the plans for Sue – it’s great that even though Sue is such an important symbol for the Field Museum, they don’t consider it a static piece. Much credit is due for the museum’s willingness to invest in their star attraction by keeping it up to the latest scientific standard. In addition, I never entirely liked how disassociated Sue was from the rest of the paleontology displays, and it’s nice to know that somebody at the museum must have felt the same way. There’s something to be said for giving the skeleton pride of place, but ultimately I think museumgoers will be better served by seeing Sue contextualized within the story of life on Earth.

While I love me some megasauropods, I can’t help but be less excited by the Patagotitan. I realize that most people don’t go to every natural history museum, but two identical casts already exist. To be fair, the Field Museum Patagotitan will be in a very different setting from its AMNH predecessor (although it may turn out rather like the Royal Ontario Museum Futalognkosaurus). Still, I would rather have seen something more unique to the Field Museum. One idea would be to bring back the Brachiosaurus reconstruction, and display it side-by-side with a remount of the historic Apatosaurus currently in Evolving Planet. Both specimens are tied to the museum’s own expeditionary history, and together would tell the remarkable story of Elmer Riggs. The Apatosaurus in particular could anchor a Field Museum retrospective, while images of the three different locations it has been displayed in since 1908.

The last time a sauropod graced the Stanley Field Hall. Source

Somebody more cynical than me might point out that switching up iconic displays is becoming a predictable way for museums to generate press and manufacture controversy. For example, the Natural History Museum in London got no less than three media splashes when they announced Dippy the Diplodocus was to be replaced, actually removed Dippy, and finally unveiled the remounted blue whale in Hintze Hall earlier this summer. Nevertheless, there is a strong case to be made that stirring up public reactions in this way is an effective way to keep the people interested in their museums. As Field Museum president Richard Lariviere told the Chicago Tribune, “the public doesn’t understand that the science…we convey is changing on an almost hourly basis here. I talk to people all the time who think that since they’ve been to the Field Museum 10 years ago they’ve seen it. By transforming the central space, we hope to convey that exact message.”

At any rate, we’re in for some great new dinosaur displays at the Field Museum over the next couple years. What do you think of the upcoming changes?

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Filed under dinosaurs, exhibits, FMNH, fossil mounts, museums, opinion, sauropods, theropods

Acrocanthosaurus, the Terror of the South

Acrocanthosaurus at the North Carolina Museum of Natural Science. Photo by the author.

Following yesterday’s travelogue about the North Carolina Museum of Natural Science (NCSM), I thought I’d go into a little more depth about the museum’s star fossil. One of only five Acrocanthosaurus specimens ever found, NCSM 14345 is the most complete and the only one on public display. The mounted skeleton has been at the Raleigh museum since 2000. Among other things, its story highlights the challenging relationship between academic paleontologists and the private fossil trade.

Despite its current home in North Carolina, this Acrocanthosaurus hails from the town of Idabel in southeast Oklahoma, more than a thousand miles away. Avocational fossil hunters Cephis Hall and Sid Love (both now deceased) discovered the skeleton in 1983. After making an arrangement with the landowner, the pair spent the next three years carefully excavating the find.

The Acrocanthosaurus was recovered from the early to mid Cretaceous rocks of the Antlers Formation. Found in a deposit of fine sandstone and dark mudstone alongside lots of lignitized wood, the animal’s final resting place was probably a stagnant swamp or pond. Additional evidence for the depositional environment comes from the way the bones are preserved. They contain a great deal of pyrite, and were encrusted with dense concretions of calcium carbonate. Both of these minerals are formed by bacteria blooms in low-oxygen locales, such as the mud at the bottom of a swamp. Gouges in the skull, ribs, and foot indicate scavengers – crocodiles and possibly other Acrocanthosaurus – were feeding on the carcass before it was buried.

All told, the find included a complete skull (the only one of its kind), the pelvis and sacral vertebrae, both arms and shoulder girdles, the right leg, and parts of the rib cage and tail. Paleontologist Richard Cifelli of the Sam Noble Museum in Norman, Oklahoma became aware of the discovery in 1987. Cifelli initially hoped that the museum could acquire the specimen for study and safekeeping, but Hall and Love’s asking price was beyond their means. Instead, Hall and Love loaned the fossils to the University of Texas. They were unsatisfied with this arrangement, however, and drove down to Austin to retrieve their dinosaur (the details of this event are apparently contentious). Hall and Love then sold the fossils to Geological Enterprises, a for-profit outfit based in Ardmore, Oklahoma, for $225,000 plus the promise of a cast once the prep work was completed. Geological Enterprises founder A. Allen Graffham gave the specimen the nickname “Fran,” after his wife.

The meticulously reconstructed Acrocanthosaurus skull. Photo by the author.

The calcium carbonate concretions and heavy pyrite content made the Acrocanthosaurus a particularly challenging fossil to prepare. The concretions are like natural cement and are very difficult to remove without damaging the bones. Meanwhile, pyrite breaks down into sulfur when exposed to oxygen and humidity, which can cause bones to crumble. In 1991, Graffham outsourced the preparation job to the Black Hills Institute in Hill City, South Dakota. Terry Wentz led the preparation project at BHI, which was reportedly one of the most challenging assignments of his career. The concretions encrusting the bones were so dense that they often had to be ground off, rather than chipped. This process could take several hours just to remove a few millimeters of calcium carbonate. To make matters worse, removing pyrite releases acidic particulates into the air. Preparators had to wear respirators and the bones had to be prepared in vacuum boxes.

The most daunting part of the project was reconstructing the specimen’s beautiful and intact skull. Although virtually complete, the skull was found crushed flat. Everyone involved agreed that the skull would be more informative and more impressive if it could be reinflated, but that was easier said then done. Over a year of work went into carefully separating the individual skull bones and reassembling them into their life position.

After five years of what was probably one of the most difficult fossil prep jobs ever attempted, the Acrocanthosaurus was ready to be sold. However, Graffham initially had trouble finding a buyer. There were interested parties in Japan, but he reportedly did not want the fossils to leave the United States.

On October 4, 1997, another well-preserved theropod skeleton went up for auction at Sotheby’s in New York. Sue – the most complete Tyrannosaurus ever found – was already legendary thanks to the protracted legal battle over the fossils. Now that the one-of-a-kind skeleton was being sold at a high profile auction, paleontologists feared that it would disappear into the hands of a private collector. On the night of the auction, most of the museums and other public repositories in the running were outbid within minutes. The North Carolina Museum of Natural Science appeared to be the only museum left after the price topped $5 million, and so the hopes of the paleontological community rested on their shoulders. NCSM dropped out at $7.2 million, and moments later Richard Gray, a veteran of art auctions, won Sue on behalf of a mysterious client. Happily, that client turned out to be the Field Museum (with financial backing from McDonald’s and Disney), and so Sue ended up in a public repository after all.

The Acrocanthosaurus and its sauropod companion can be seen from the ground and from a balcony. Photo by the author.

Still, NCSM had been willing to stake an enormous amount of money on a name brand dinosaur, and they weren’t about to give up. Two months after the Sue auction, the Friends of the North Carolina Museum of Natural Sciences bought the Acrocanthosaurus from Graffham’s company for $3 million. BHI prepared the mount, which debuted along with the rest of the museum’s new building on April 7, 2000. It may not be coincidental that this was just one month before the mounted skeleton of Sue was unveiled in Chicago.

The Acrocanthosaurus occupies a well-lit, circular atrium on the museum’s third floor. Visible both from the ground and from a balcony, the mount is accompanied by a rather goofy-looking sauropod statue. Model pterosaurs circle overhead on a rotating arm, and recreations of theropod and sauropod tracks from Dinosaur State Park in Paluxy, Texas can be seen throughout the room. The original skull is on display in a case outside the atrium.

Sadly, pyrite deterioration has continued to ravage the delicate fossils. Several of the original bones once included in the NCSM mount have been retired to the collections for safekeeping. As of this year, only the arms, right foot, and vertebrae appear to be original material. The rest have been replaced with casts.

Exhibit signs have also changed since the 2000 debut. NCSM exhibits staff learned from surveys that 80% of visitors thought the dinosaur on display was a T. rex, and plenty more assumed the whole skeleton was a replica. In response, most of the signage was redesigned. The displays now highlight the differences between “Acro” and T. rex, and highlight the exceptional rarity of the museum’s Acrocanthosaurus specimen.

A number of NCSM 14345 casts are on display at museums throughout North America, including the Virginia Museum of Natural History, the Houston Museum of Nature and Science, and the Kenosha Public Museum. As promised, Hall and Love were awarded a complete cast of the skeleton,  but without the means to assemble or display it, the replica sat in storage for several years. Eventually, local third and fourth graders successfully raised the $150,000 needed to display the cast at the Museum of the Red River in Idabel.

Acrocanthosaurus cast at the Virginia Museum of Natural History. Photo by the author.

Acrocanthosaurus cast at the Houston Museum of Nature and Science. Photo by the author.

Fossils are precious remains of real organisms, clues about ecosystems from long ago and the making of the world as we know it today. In an ideal world, all significant fossils would, from the moment of their discovery, be accessioned and held in a public collection at a museum or university. A fossil sitting on somebody’s mantelpiece or waiting to be sold at auction is doing nothing to grow our collective knowledge. However, public institutions don’t have the resources to find and excavate every fossil, and in the United States fossils found on private land belong to the landowners. That means that, for better or worse, there is a thriving commercial market for rare fossils.

A plurality of paleontologists do not engage with fossil dealers for ethical reasons. Indeed, even if they wanted to buy rare specimens, academic institutions can seldom match the prices individual collectors are willing to pay. Museums don’t usually have $3 million sitting around. That kind of money could fund a whole research team for years. As such, we’re left with a Catch-22. Paleontologists want important fossils to be in museums where they can be seen and studied by everyone. But if those fossils are in private hands, buying them would support and legitimize the industry that is also keeping fossils out of public collections. If there was an easy solution, it would have been worked out by now.

Nevertheless, serendipity occasionally strikes. This seems to have been the case with the Acrocanthosaurus. News about Sue generated interest in buying a name-brand dinosaur, and donors were willing to put up the money to get the specimen for NCSM. The skeleton is now in a public collection, at a free museum, no less. Meanwhile, the collectors were well compensated for their considerable investment. It’s hard to chalk that up as anything but a win, all around.

References

Carpenter, K. 2016. Acrocanthosaurus Inside and Out. Norman, OK: University of Oklahoma Press.

du Lac, J.F. 2014. The T. rex that got away: Smithsonian’s quest for Sue ends with different dinosaur. The Washington Post

Eddy, D.R. and Clarke, J.A. 2011. New Information on the Cranial Anatomy of Acrocanthosaurus atokensis and Its Implications for the Phylogeny of Allosauroidea (Dinosauria: Theropoda). PLoS ONE 6:3:e17932.

Lovelady, W. 2012. Every Step You Take. Exhibits and Emerging Media, North Carolina Museum of Natural Science. 

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Filed under dinosaurs, fossil mounts, museums, reptiles, theropods

The National Fossil Hall Rejects

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

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

Stegomastodon (USNM 10707)

Stegomastodon in 2014. Photo by the author.

The Stegomastodon in 2014. Photo by the author.

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

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

Paramylodon (USNM V 15164)

Collections staff

Collections staff wheel Paramylodon out of the exhibit hall. Source

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

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

Zygorhiza (USNM PAL 537887)

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

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

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

Tapirs, Horses, and Oreodonts

Photo by the author.

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

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

Brachyceratops (USNM 7953)

Brachyceratops/Rubeosaurus

Brachyceratops/Rubeosaurus. Photo by NMNH Department of Paleobiology.

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

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

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

Corythosaurus (USNM V 15493)

Corythosaurus as seen in 1960s

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

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

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

Assorted Dinosaur Skulls

Triceratops skull

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

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

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

Dolichorynchops (USNM PAL 419645)

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

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

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

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

References

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

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

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

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

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

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

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