Category Archives: Extinct Monsters

Permo-Triassic Synapsids at NMNH

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In the middle decades of the 20th century, museum theory and paleontological science were undergoing complementary revolutions. Museum workers shrugged off their “cabinet of curiosity” roots and embraced visitor-centric, education-oriented exhibits. Designers began to envision the routes visitors would travel through an exhibit space, and consider how objects on display could contribute to holistic stories. Meanwhile, paleontologists like Stephen J. Gould and David Raup moved their field away from purely descriptive natural history, exploring instead how the fossil record could inform our understanding of evolution and ecology. The common thread between both transitions was a focus on connections – bringing new meaning and relevance to disparate parts by placing them in a common narrative.

Between 1953 and 1963, the Smithsonian implemented an institution-wide modernization program, transforming virtually every exhibit in the museum complex. The National Museum of Natural History began renovations to its classic fossil halls in 1959, and the new exhibits were emblematic of contemporary trends in both museum design and paleontology. The plan, as devised by exhibit designer Ann Karras, was to do away with the loose arrangement of specimens and turn the east wing into a guided narrative of the biological and geological history of Earth. Responsibility for selecting specimens and writing label copy in each of the four halls fell to a different curator. In Hall 2, which housed dinosaurs and fossil reptiles, that curator was Nicholas Hotton.

Layout of the USNM east wing, circa 1963.

Layout of the NMNH east wing as of 1963.

Hotton joined NMNH in 1959 as an Associate Curator of Paleontology. Entirely onboard with Karras’s vision and the paleobiology movement as a whole, Hotton described the old exhibits as “crowded” and “unorganized.” He thought NMNH had plenty of dinosaurs, but “mammal-like reptiles”* were sorely needed if Hall 2 was to tell the complete story of amniote evolution. Following that, Hotton’s mission over the next several years was to assemble a respectable collection of synapsid specimens for NMNH, and to incorporate them into a well-illustrated exhibit on the origins of mammals. This post highlights just a few of the specimens featured in Hotton’s version of Hall 2.

*In Hotton’s day, early mammalian relatives were usually called “mammal-like reptiles”, hence their inclusion in the fossil reptile exhibit. Today, most specialists prefer a more precise definition of reptiles that excludes synapsid (mammal-line) animals. In this post, I will be using the modern classification wherever possible. 

The Dimetrodon

Prior to 1960, the non-mammalian synapsid collections at NMNH were mostly limited to early Permian pelycosaurs. The most impressive of these was a Dimetrodon gigas collected in 1917 by independent fossil hunter Charles Sternberg. One of the best collectors of his day, Sternberg worked intermittently for E.D. Cope, O.C. Marsh, and various North American museums. In the summer of 1917, however, Sternberg was on a personal collecting trip with his son Levi. Their target was the Craddock Ranch bone bed of Baylor County, Texas, which was first explored in 1909 by a University of Chicago team. Sternberg was already quite familiar with this part of western Texas, having made some of the first thorough surveys of the Permian “red beds” in the 1880s, but the site itself was new to him. Nevertheless, Sternberg was extraordinarily successful that summer, collecting hundreds of fossils from a wide range of animals. He offered this bounty to the Smithsonian, and they purchased it from him immediately.

The Craddock Ranch fossils were particularly appealing because of their unique preservation. Buried in soft clay at the bottom of a shallow pond, the fossils could be removed from the ground with relative ease, and were largely free of encrusting matrix. Although few of the bones were articulated, many were identifiable. All told, the Sternberg collection included at least 35 skulls and partial skeletons from amphibians like Cardiocephalus, Diplocaulus, and Seymouria, plus hundreds of individual Dimetrodon bones, and a single articulated Dimetrodon specimen.

Note short tail

An early photograph of the Dimetrodon mount. Image from Gilmore 1919.

Dimetrodon first displaed on north wall

The Dimetrodon was first displayed on the north wall of the Hall of Extinct Monsters. Source

That Dimetrodon (USNM 8635) was the basis for a mount constructed by T.J. Horne. The articulated skeleton included a complete series of presacral vertebrae, the shoulder girdles, most of the forelimbs, and the left femur and tibia. The skull and jaw bones were found disarticulated, but bound together in the same mass of matrix as the skeleton. Horne added the pelvic bones and sacrum from smaller Dimetrodon specimens, and sculpted the rest of the missing material in plaster to complete the mount. Notably, his reconstructed tail was extremely short and stubby. Although the American Museum and Field Museum already had Dimetrodon mounts on display, the NMNH version stood out because of its open jaws, which Charles Gilmore said “gives the animal an appearance of angrily defying one who has suddenly blocked his path.”

Gilmore added the Dimetrodon to the Hall of Extinct Monsters in 1918. Like the other standing mounts constructed under Gilmore’s supervision, the skeleton was placed on a base textured and painted to resemble the rocks in which it was found. At this point in time, the NMNH fossil halls lacked any overarching organizational scheme, and interpretive content was minimal. Nevertheless, Gilmore displayed the Dimetrodon mount with both a small model and a 15-foot oil painting by Garnet Jex, which provided general audiences a better understanding of the animal’s life appearance.

dimetrodon

Dimetrodon in the 1963 fossil reptiles exhibit. Image courtesy of the Smithsonian Institution Archives.

Dimetrodon in 2014. Photo by the author.

Dimetrodon after the 1981 renovation. Photo by the author.

During the 1962 renovation, Hotton re-contextualized the classic Dimetrodon mount as a mammal ancestor. Unmissable orange arrows pointed to the specific anatomical traits that signify the animal’s kinship with mammals, including heterodont teeth and a single temporal fenestra. By design, visitors would pass Dimetrodon before visiting the true mammals in the adjacent hall.

The Dimetrodon skeleton itself was altered during the next renovation in 1981, when it was placed on a new, untextured base and given a longer replica tail. Contemporary staff also repainted the plaster sections to more closely resemble the original fossils – a surprising reversal of Gilmore and Horne’s original intention to make the reconstructed bones obvious to viewers.

The Thrinaxodon

Pelycosaurs like Dimetrodon represent the first major synapsid radiation, but by the middle Permian they were almost entirely replaced by therapsids. A more derived group which includes modern mammals, therapsids spread across the globe and became increasingly diverse as the Permian progressed. From weasel-sized burrowers to multi-ton herbivores, non-mammalian therapsids were among the first animal groups to conquer a wide range of terrestrial niches. Hotton wanted to tell this story in the modernized fossil exhibit, but there were hardly any non-mammalian therapsids in the NMNH collections. To correct this problem, Hotton took to the field for several months in 1960, and again in 1961. He joined James Kitching in exploring the Beafort Group rocks of South Africa, which were known to produce plentiful Permian and Triassic vertebrate fossils. Hotton returned to the museum with over 200 new specimens, the best of which were used in the renovated exhibit.

Hotton’s display of South African synapsids and amphibians. Note “Baby Doll” on the far left. Photo courtesy of the Smithsonian Institution Archives.

Thrinraxodon with Cynognathus skull

Thrinaxodon paired with Cynognathus skull. Photo by the author.

Hotton’s most prized find from South Africa was a gorgeously preserved and nearly complete Thrinaxodon liorhinus (USNM 22812). Hotton called this specimen “Baby Doll”, and while it was not prepared in time for Hall 2’s 1963 opening, it would later earn a spot of honor in the exhibit. Before that happened, though, Baby Doll was actually stolen by an over-enthusiastic volunteer. The FBI located and returned the fossil a year and a half later.

Since the 1980s, the Thrinaxodon has been displayed alongside the skull of Cynognathus crateronotus (USNM 22813), which Hotton collected on the same expedition. Both are members of the cynodont clade, which includes some of the closest relatives of modern mammals.

 The Daptocephalus

Less than a month after hall 2 reopened, Nicholas Hotton returned to South Africa. This time, he was accompanied by his spouse Ruth Hotton and their three young children. For seven months, the Hottons traveled among fossil sites on different ranches, camping most nights. They collected some 300 specimens for the Smithsonian, and Hotton’s biostratigraphic mapping of the Beaufort Group brought a measure of clarity to this region’s historically convoluted geology.

Ruth Hotton made one of the trip’s most impressive finds while prospecting in a dry riverbed with her daughter, Carol (who is now a paleobotanist at NMNH). Turning a corner, she stumbled upon a dicynodont skeleton, completely exposed and lying in the middle of the channel. One can only imagine the surprise and delight of finding an articulated fossil skeleton completely uncovered. If the Hottons had been there one season earlier or one season later, the river would have undoubtedly destroyed the fossils.

Daptocephalus on display. Photo by James Di Loreto, National Museum of Natural History.

Back at the museum, Nicholas Hotton prepared the specimen (USNM 299746) and determined it to be Daplocephalus leoniceps, one of the plethora of dicynodonts known from the Beaufort Group. Based on this classification, he reconstructed the damaged skull to resemble more complete Daplocephalus specimens, and added casts of Daplocephalus limbs.

The specimen was restored in 2019 and is now labeled Platypodosaurus. Photo by the author.

As it turns out, however, USNM 299749 is not a Daplocephalus—it is a somewhat distantly related dicynodont currently called Platypodosaurus. To varying degrees, fossil mounts are hypotheses made of bone and plaster. They are based on the best information available at the time, but sometimes they need to be corrected. The NMNH “Daplocephalus” had been mislabeled and erroneously reconstructed for many years, but the 2014 renovation of the NMNH fossil halls now presented an opportunity to deconstruct the specimen and study it up close. As of 2019, Platypodosaurus was back on display with a newly reconstructed skull and limbs.

Thanks to Christian Kammerer for kindly sharing images and insight on “Daptocephalus”!

References

Gilmore, C.W. (1919). A Mounted Skeleton of Dimetrodon gigas in the United States National Museum, with Notes on the Skeletal Anatomy. Proceedings of the United States National Museum 56:2300:525-539.

Kammerer, C. (2015). Personal communication.

Lay, M. (2013). Major Activities of the Division of Vertebrate Paleontology During the 1960s. http://paleobiology.si.edu/history/lay1960s.html

Marsh, D.E. (2014). From Extinct Monsters to Deep Time: An ethnography of fossil exhibits production at the Smithsonian’s National Museum of Natural History. http://circle.ubc.ca/handle/2429/50177

Sepkoski, D. (2012). Rereading the Fossil record: The Growth of Paleobiology as an Evolutionary Discipline. Chicago, IL: The University of Chicago Press.

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Extinct Monsters: Basilosaurus

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The National Museum of Natural History houses the world’s most complete assemblage of fossil marine mammals. The crown jewel of this collection is assuredly the historic mounted Basilosaurus, which was until recently the only mount of its kind composed of original fossils. Since 2008, this ancestral whale has been suspended from the ceiling of the Sant Ocean Hall, but these fossils have actually been on near-continuous display for 120 years and counting. Technically this wasn’t the first time Basilosaurus fossils were used in a mounted skeleton (Albert Koch’s absurd chimera “Hydrarchos the sea serpent” preceded it by 60 years), but it was the first time this species was mounted accurately and under scientific supervision.

Basilosaurus was named by anatomist Richard Harlan in 1834. The name means “king lizard”, since he erroneously thought the bones belonged to a giant sea-going reptile. Richard Owen later re-identified the bones as those of a whale, and coined the new name “Zueglodon” (yoke tooth). While the International Code of Zoological Nomenclature decrees that the first published name must be used, late 19th century paleontologists apparently preferred to use Owen’s junior synonym.

Note basilo

Basilosaurus cast in the original USNM, now called the Arts and Industries Building. Photo courtesy of the Smithsonian Institution Archives.

In 1884 Charles Schuchert, an Assistant Curator at the United States National Museum, went to Clarke County, Alabama in search of “Zueglodon” remains. This would be the very first fossil-hunting expedition ever mounted by the Smithsonian. Decades earlier, Koch came to the same region to collect the fossils he used to assemble Hydrarchos, and local people had been familiar with the whale bones long before that.

Schuchert did not find the complete Basilosaurus skeleton he was looking for, but he did recover a reasonably complete, albeit fragmented, skull and jaw. He returned to Alabama in 1886 and collected an articulated vertebral column, a pelvis, and enough other elements to assemble a composite skeleton. Museum staff used the fossils to produce plaster casts, and combined them with sculpted bones to construct a replica “Zueglodon.” The whale was first unveiled at the Atlanta Exposition in 1895, before finding a home in the original United States National Museum (now the Arts and Industries Building). The 40-foot skeleton hung from the ceiling of the southwest court, with the original fossils laid out in a long case beneath it.

Basilosaurus as the centerpiece of the Hall of Extinct Monsters sometime before 1930. Photo courtesy of the Smithsonian Institution Archives.

In 1910, the USNM relocated to a larger building on the north side of the national mall, which is now of the National Museum of Natural History.  The east wing of the new museum became the Hall of Extinct Monsters, and has been the home of fossil displays at the Smithsonian ever since. The Basilosaurus was selected as the centerpiece of the new display, as its great length and toothy appearance made it popular with visitors. In honor of the occasion, preparator James Gidley reworked the old plaster mount to incorporate Schuchert’s original fossils. A series of caudal vertebrae from a third Basilosaurus specimen was also used. Still labeled “Zueglodon”, the mount was completed in 1912, about a year after the Hall of Extinct Monsters first opened to the public. As Curator of Geology George Merrill explained, the wide-open floor plan of the new hall allowed visitors to walk all the way around the mount, and inspect its every aspect up close.

During the 1960s and 70s, Basilosaurus occupied a case in the fossil mammal exhibit in Hall 5. Photo courtesy of the Smithsonian Institution Archives.

In 1931, the Basilosaurus was upstaged by a new centerpiece: the mounted Diplodocus that took Charles Gilmore and his team more than a decade to assemble. The Diplodocus took the front-and-center position (where it remained until 2014), while the Basilosaurus was relocated to the south side of the hall. The Great Depression and World War II ensured that the east wing exhibits remained largely unchanged for nearly three decades after that, but the space was eventually renovated in the early 1960s as part of a Smithsonian-wide modernization campaign. In its new incarnation, the east wing’s open spaces were carved into smaller galleries dedicated to different groups of ancient life. With the central Hall 2 occupied by dinosaurs and fossil reptiles, the Basilosaurus joined the other Cenozoic mammals in Hall 5. This gallery became “Life in the Ancient Seas” in 1989, but the Basilosaurus remained in place.

The Basilosaurus was in the Ancient Seas gallery from 1989 to 2008.

For the Ancient Seas gallery, Basilosaurus was remounted with an arched tail. Photo by Chip Clark.

Life in the Ancient Seas was a very different setting for the Basilosaurus than the Hall of Extinct Monsters, reflecting the significant changes in museum interpretation that occurred during the 20th century. The historic exhibit showcased the breadth of the museum’s fossil collection in a fairly neutral environment. Interpretation was minimal, and generally intended for a scholarly audience. In contrast, Life in the Ancient Seas was an immersive educational experience (no pun intended). The Basilosaurus and other marine mammal skeletons were posed over a papier-mâché ocean bottom, while a blue and turquoise color palate and even shimmering lights contributed to the illusion of traveling through an underwater world. Combined with text panels written with a jovial, inviting tone, the net effect was an exhibit pitched to a general audience at home with multimedia.

The historic Basilosaurus

The historic Basilosaurus, remounted for display in the Ocean Hall. Photo by the author.

The Basilosaurus was moved once more in 2008, when it was incorporated in the enormous new Ocean Hall. In its 5th position in a little over a century, the skeleton now hangs from the ceiling as part of an exhibit on whale evolution. Moving the historic skeleton was not an easy task, and took about six months of work. NMNH staff collaborated with Research Casting International to disassemble the skeleton, stabilize and conserve each bone, and finally remount the Basilosaurus on a new armature. In the new mount, each bone rests in a custom cradle with felt padding, to prevent vibration damage caused by the crowds passing beneath it. Smithsonian paleontologists also reunited the whale with its hind legs, which Schuchert found alongside the articulated vertebral column in Alabama but were, until recently, thought to belong to a bird.

This latest setting for Basilosaurus is a happy medium between museums past and present. The historic gallery occupied by the Ocean Hall has been restored to its original neoclassical glory, and much like the original Hall of Extinct Monsters visitors have clear sight lines across the space. Rather than being led on rails through a scripted exhibit experience, visitors can move freely through the gallery, bouncing among the objects they find compelling. At the same time, however, the Basilosaurus is explicitly contextualized as an example of the transformative power of evolution. Presented alongside cast skeletons of Maiacetus and Dorudon, this display makes whales’ evolutionary link to terrestrial mammals crystal clear.

This post was last updated on 1/8/2018.

References

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 No. 90.

Marsh, D.E. (2014). From Extinct Monsters to Deep Time: An ethnography of fossil exhibits production at the Smithsonian’s National Museum of Natural History. http://circle.ubc.ca/handle/2429/50177

Meet Basilosaurus, an Ancient Whale (2008). Smithsonian Institution. http://www.mnh.si.edu/exhibits/ocean_hall/meet_basilosaurus.html

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Extinct Monsters Updated

artists conception

This early artist’s conception of the new NMNH fossil hall was on display on closing day.

Way back in 2012, I wrote a series of posts on the history of fossil displays at the National Museum of Natural History. Now that the old exhibit is closed for five years of renovation, it seemed like a good idea to go back and revise the old articles. That, and it can be very painful to read things I wrote over a year ago. Each of the seven posts, plus the launch page, have been substantially updated with new information, new images, and less abuse of the passive voice. You can check out the new articles via the Extinct Monsters link at the top of the page, or by clicking here.

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Extinct Monsters: Brachyceratops

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Most of the mounted dinosaur skeletons at the National Museum of Natural History (NMNH) represent taxa that are well-known to casual paleontology enthusiasts. But nestled amongst household names like Triceratops, Stegosaurus and Diplodocus is an easily-overlooked horned dinosaur that was historically called Brachyceratops montanensis (it’s currently labeled Styracosaurus sp). Tucked away in a glass case behind the giant Triceratops, this pocket-sized ceratopsian may not be the most spectacular display in the exhibit, but it is nevertheless an important one for the Museum. Discovered in 1913 by the Smithsonian’s own Curator of Fossil Reptiles Charles Gilmore, Brachyceratops represents one of only a few dinosaur species excavated, prepared, described and exhibited entirely in-house at NMNH. It is therefore unfortunate that modern researchers have banished the name Brachyceratops to the realm of taxonomic obscurity. What’s more, the days of the Brachyceratops mount, on exhibit since 1922, are numbered: when the NMNH paleontology halls closed for renovation in April 2014, this specimen was be retired to the collections, and is not planned for inclusion when the exhibit reopens in 2019.

The Brachyceratops mount today. Photo by the author.

The Brachyceratops mount today. Photo by the author.

During his tenure at NMNH, Gilmore was an inexhaustibly productive writer, publishing at least 170 scientific articles, including numerous important descriptions and reassessments of fossils discovered by O.C. Marsh’s teams in the 19th century. However, Gilmore was much happier studying fossils in his lab than excavating new finds in the field, taking part in a scant 16 NMNH-sponsored field expeditions over the course of his career. A 1913 trip to the Cretaceous Two Medicine Formation in Northeast Montana was therefore unusual for Gilmore. He was following in the footsteps of Eugene Stebinger of the US Geological Survey, who had reported the previous year that the region was only minimally explored but clearly awash in vertebrate fossils.

On this inaugural fossil prospecting trip, Gilmore’s team located abundant remains of fish, small reptiles and dinosaurs, especially hadrosaurs and ankylosaurs. The most notable find, however, was a small bone bed (about six feet square) of ceratopsian fossils, representing at least five individuals. Gilmore described this find in a 1917 monograph, naming the dinosaur Brachyceratops montanensis. Today we know that ceratopsians were quite diverse, particularly during the Campanian, but in the early 20th century the true extent of the group was only just being revealed. Still, it was clear to Gilmore that at an estimated six feet in length, Brachyceratops was an unusually small ceratopsian. He proposed that it may have fed on different plants or occupied a different niche than larger contemporaries like Centrosaurus and Styracosaurus.

pretty art

Reconstruction of Brachyceratops holotype skull. Plate from Gilmore 1917.

In 1917, most of the dinosaur mounts on display at NMNH came from fossils collected by Marsh for the US Geological Survey, and many represented species also on display in New York, Pittsburgh and New Haven. Accordingly, Gilmore was doubtlessly enthused by the prospect of displaying a dinosaur exclusive to Smithsonian. He awarded the task of creating a Brachyceratops mount to preparator Norman Boss, who would spend 345 working days on the project. Of the five individuals found in Montana, USNM 7953 was selected as the basis for the mount because it was the most complete, with the sacrum, pelvis, femora and complete set of caudal vertebrae found articulated in situ. Helpfully, Gilmore published a list of precisely which parts of the mount came from which individual specimen (see below). This was a marked contrast from some of his contemporaries at other museums, who would not bother to record such information, or even actively obscure how many disparate specimens they were using to build their mounts.

Gilmore's helpful list

A helpful breakdown of the Brachyceratops mount from Gilmore 1922.

Boss based his restoration of Brachyceratops closely on the complete, articulated Monoclonius (=Centrosaurus) specimen (AMNH 5351) discovered by Barnum Brown in 1914. In particular, Boss replicated the angle of the scapulae and the number of vertebrae (22) on the American Museum of Natural History skeleton. Missing bones and portions thereof were sculpted in plaster, easily recognized by their solid color and smooth texture. Just as Gilmore and Boss had done with their 1905 Triceratops mount, the Brachyceratops was given strongly flexed elbows. According to Gilmore, a very large olecranon process on the ulna would have forced all ceratopsians into this somewhat awkward stance. Of particular note is the restoration of the skull, which was found shattered into dozens of pieces, many smaller than one inch. A close look at the specimen reveals how Boss painstakingly reassembled these fragments. Unfortunately, this is difficult in the exhibit hall because the mount is posed with the side of the skull that is mostly plaster facing visitors.

Norman Boss Brachyceratops courtesy Smithsonian archives

Norman Boss puts the finishing touches on the Brachyceratops mount. Photo courtesy of the Smithsonian Archives.

The completed Brachyceratops mount was placed on exhibit in 1922, on the same pedestal in the Hall of Extinct Monsters as the Triceratops. The substrate beneath the mount was colored and textured to match the Two Medicine Formation sandstone in which the fossils were found. Gilmore also prepared one of his charming models of Brachyceratops, mirroring the pose of the mount, but it is unclear whether it was ever exhibited.

woo triceratops

Brachyceratops on exhibit with Triceratops. Plate from Gilmore 1922.

The Brachyceratops has remained on view through each subsequent renovation of the fossil halls, always placed close to Triceratops. This close association has prompted many visitors to mistake the diminutive Brachyceratops for a baby Triceratops, and in fact these visitors are on the right track. While Gilmore always described Brachyceratops as an unusually small but full-grown ceratopsian, Scott Sampson and colleagues confirmed in 1997 that all five specimens were juveniles. A century’s worth of new fossil discoveries has provided modern paleontologists with a thorough understanding of ceratopsian ontogeny, and characteristics like the unfused nasal horn clearly mark the mounted Brachyceratops as a young animal. Unfortunately, Gilmore’s Brachyceratops specimens lack any good diagnostic features that could link it to an adult form. According to Andrew McDonald, the most likely candidate is Rubeosaurus ovatus, which was, incidentally, discovered by Gilmore on a 1922 repeat trip to the Two Medicine site. 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 mounts to include in a renovated gallery. 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. It’s not all bad, though. Taking these fossils off exhibit will make them more accessible to researchers, and allow them to be closely examined in all aspects for the first time in decades. Perhaps one day soon we will have a clearer idea of the identity of one of Gilmore’s great finds.

References

Gilmore, C.W. (1917). Brachyceratops, a Ceratopsian Dinosaur from the Two Medicine Formation of Montana, with Notes on Associated Fossil Reptiles. Washington, DC: US Geological Survey.

Gilmore, C.W. (1922). The Smallest Known Horned Dinosaur, Brachyceratops. Proceedings of the US National Museum 63:2424.

Gilmore, C.W. (1930). On Dinosaurian Reptiles from the Two Medicine Formation of Montana. Proceedings of the US National Museum 77:2839.

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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The NMNH fossil halls, circa 1963

c.02

A revamp for the dinosaur displays in Hall 2. Courtesy of the Smithsonian Institution Archives.

Since the NMNH building opened in 1910 as the United States National Museum, the east wing has been home to fossil displays. Although there have been many small adjustments and additions to the exhibits over the years, we can separate the east wing’s layout into three main periods. From 1910 t0 1945, the exhibits were primarily under the stewardship of Charles Gilmore. Called the “Hall of Extinct Monsters”, this iteration was somewhat haphazard in its layout and generally resembled a classic “cabinet of curiosity” approach to exhibit design. Gilmore’s version of the east wing remained in place until 1963, when the space was redesigned as part of the Smithsonian-wide modernization project. In the updated halls, there was a directed effort to compartmentalize exhibits based on the subdivisions of the Museum’s research staff, with each area of the gallery becoming the responsibility of a different curator. A second renovation was carried out in several stages starting in 1980. This version, which was open until 2014, was part of the new museology wave that started in the late 1970s. As such, the exhibits form a more cohesive narrative of the history of life on earth, and much of the signage carries the voice of educators, rather than curators.

Of course, the field of paleontology has advanced by leaps and bounds since the early 1980s, and NMNH staff have made piecemeal updates to the galleries when possible, including restorations of deteriorating mounts, and additional signage that addresses the dinosaurian origin of birds and the importance of the fossil record for understanding climate change. A third renovation is currently underway and will be completed in 2019.

But I’m getting ahead of myself. The purpose of this post is to provide an overview of the NMNH fossil halls as they stood in 1963, after the first major renovation. This iteration of the east wing was long gone before I was born, so this information is pieced together from historic photographs, archived exhibit scripts, and correspondence among the individuals involved in the modernization project (my thanks to the staff of the Smithsonian Institution Archives for their assistance in accessing these materials). Perhaps unsurprisingly, records of the dinosaur gallery are by far the most thorough. Information on the other halls is considerably harder to come by, so if any readers who saw the older exhibits in person remember any details, it would be fantastic if you could share them.

Layout of the USNM east wing, circa 1963.

Layout of the USNM east wing, circa 1963.

As mentioned, the Smithsonian underwent a thorough modernization project in the middle of the 20th century. The modernization committee, chaired by Frank Taylor (the eventual director-general of Smithsonian museums), was established in 1948. Under the committee’s guidance, most of the institution’s exhibits were redesigned between 1953 and 1963. Keep in mind that at the time, the United States National Museum was the only Smithsonian museum – it would not be divided into the National Museum of Natural History and the National Museum of History and Technology (now the National Museum of American History) until 1964.

Completed in 1963, the USNM fossil exhibits were among the last to be modernized. Only a small number of specimens were added that had not already been on view in the previous version of the space – in fact, many specimens were removed. The changes primarily focused on the layout of the exhibit, turning what was a loosely organized set of displays into a series of themed galleries. The east wing included four halls in 1963, the layout of which can be seen in the map above. Each hall was the responsibility of a particular curator. Nicholas Hotton oversaw Paleozoic and Mesozoic reptiles in Hall 2. David Dunkle was in charge of fossil fish in Hall 3. Porter Kier oversaw fossil invertebrates and plants in Hall 4. Finally, Charles Gazin, head curator of the Paleontology Division, was responsible for Cenozoic mammals in Hall 5. Each curator had a central role in selecting specimens for display and writing accompanying label copy.

Invertebrates and Fossil Plants

echinoderms1961

Echinoderm fossil display in Hall 4. Courtesy of the Smithsonian Institution Archives.

It is likely that part of the reason the fossil halls were late on the modernization schedule was that the curators of the Paleontology Division were not terribly interested in exhibits or outreach. There were no staff members in the division exclusively devoted to exhibit work, so the task of designing the new exhibit space was an added burden for the research staff. As invertebrate paleontology curator G. Arthur Cooper put it in a 1950 memo, “all divisions of Geology at present are in an apathetic state toward exhibition.”

Nevertheless, work on the east wing halls had begun by 1957, if not a bit earlier. The first of the new exhibits to be worked on was Hall 4, featuring fossil invertebrates and plants. The long and narrow space was divided into four sections: the first introduced the study of fossils and how they are preserved, the second was devoted to paleobotany, the third contained terrestrial and marine invertebrates, and the forth provided an overview of geological time. Cooper described the new exhibit as a progressive story of the expansion of life, “its stem connecting all life which is now culminating in man.”

Carboniferous coal swamp fossils in Hall 4. Photo courtesy of the Smithsonian Institution Archives.

In addition to a variety of fossil specimens, Hall 4 featured a series of dioramas built by George Merchand, an exhibit specialist from Ann Arbor, Michigan. Merchand built at least 4 dioramas between 1957 and 1958, each depicting representative invertebrate marine fauna from a different Paleozoic period. Most, if not all, of these dioramas were retained during the 1980s renovation and remained on view through 2014.

Fossil Fishes and Amphibians

Fossil fishes in Hall 3. Photo courtesy of the Smithsonian Institution Archives.

Fossil fish and a smattering of amphibians were located in Hall 3, on the far east side of the wing. This space would be converted into “Mammals in the Limelight” in the 1980s. David Dunkle, for whom everyone’s favorite placoderm Dunkleosteus is named, was in charge of this gallery during his tenure at USNM between 1946 and 1968. The specimens on view were arranged temporally, starting with placoderms on the south side and progressing into actinopterygians and basal amphibians on the north end. Among the more prominently displayed specimens were Xiphactinus, Seymouria, and “Buettneria” (=Koskinonodon). The hall also contained a replica of the recently discovered modern coelacanth, and small diorama of a Carboniferous coal swamp.

Dinosaurs and Other Reptiles

Dinosaurs in Hall 2, as seen facing west. Photo courtesy of the Smithsonian Institution Archives.

Hall 2, featuring dinosaurs and other reptiles, was the main draw for most visitors. It was not, however, a major priority for the Smithsonian research staff. The museum had not had a dinosaur specialist since Gilmore passed away in 1945 and indeed, dinosaurs were not an especially popular area of study among mid-century paleontologists in general. As such, responsibility for Hall 2 fell to Nicholas Hotton, at the time a brand-new Associate Curator. Later in his career, Hotton would be best known as an opponent to the dinosaur endothermy movement, but in the early 1960s he was most interested in early amniotes and the origin of mammals.

Hotton’s display of South African synapsids and amphibians. Photo courtesy of the Smithsonian Institution Archives.

Perhaps due to the general disinterest among USNM curators, changes to the dinosaur exhibits were mostly organizational. Most of the free-standing dinosaur mounts built by Gilmore and his team were collected on a single central pedestal. Preferring not to tackle the massive undertaking of disassembling and remounting the 70-foot Diplodocus skeleton, the exhibit designers left the sauropod in place and clustered the smaller moutns around it. In the new arrangement, the Diplodocus was flanked by the two Camptosaurus and prone Camarasaurus on its right and by Triceratops and Brachyceratops on its left. The Stegosaurus stenops holotype, splayed on its side in a recreation of how it was first discovered, was placed behind the sauropods at the back of the platform.

Close up of Thescelosaurus on the south wall. Photo courtesy of the Smithsonian Institution Archives.

 The north and south walls of Hall 2 were lined with additional specimens. On the south side, Gilmore’s relief mounts of Ceratosaurus and Edmontosaurus (called “Anatosaurus” in this exhibit) were joined by the gallery’s one new dinosaur, a relief mount of Gorgosaurus in a death pose. The north wall featured a long, narrow, glass-enclosed case illustrating the basics of dinosaur classification. In addition to saurischian and ornithischian pelves, the case featured skulls representing most of the major dinosaur groups. Amusingly, all but two of these skulls (Triceratops and Diplodocus) were labeled with names that are no longer considered valid. These skulls included “Antrodemus” (Allosaurus), “Trachodon” (Edmontosaurus) “Procheneosaurus” (probably Corythosaurus)  and “Monoclonius” (Centrosaurus).

In the southwest corner of Hall 2 (where FossiLab is today), visitors could see the Museum’s two free-standing Stegosaurus: the fossil mount constructed by Gilmore in 1913 and the charmingly ugly papier mache version, which had received a fresh coat of paint. Finally, the rear (east) wall of Hall 2 held Gilmore’s relief mounted Tylosaurus.

Mammals

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Brontotherium and Matternes’ Oligocene mural in Hall 5. Photo courtesy of the Smithsonian Institution Archives.

Fossil mammals were exhibited in Hall 5, a corridor-like space accessible from the main rotunda and via two doorways on the north side of Hall 2. After 1990, this space would house the “Life in the Ancient Seas” exhibit. Charles Gazin, head curator of the Division of Paleontology, was in charge of this space on paper, but my impression is that his attention was elsewhere during its design and construction. Gazin was apparently approached by the modernization committee several times during the 1950s, but was reluctant to commit his time to a major renovation project. Gazin had been spending a great deal of time at a Pliocene dig site in Panama, and the collection of new fossils proved more interesting than designing displays. As Gazin tersely explained, “It is a little difficult to concentrate objectively on exhibition problems here in the interior of Panama.”

Basilosaurus and Cenozoic reptiles in Hall 5. Photo courtesy of the Smithsonian Institution Archives.

Nevertheless, Gazin’s interest in Cenozoic mammals ensured that his gallery was exceptionally thorough. Thanks to Gazin’s own collecting expeditions throughout the 1950s, the new fossil mammals galleries contained representatives of nearly all major mammal groups, from every epoch from the Paleocene through the Pliocene (the Pleistocene was deliberately excluded, as a separate ice age exhibit was also in the works). Classic mounts from the Gilmore era like Basilosaurus and Teleoceras were joined by dozens of less showy specimens like rodents, small perissodactyls, and early primates. The new exhibit also introduced the first wave of Jay Matternes’ much-beloved murals, illustrating the changing flora and fauna in North America over the course of the Cenozoic.

Unveiling and Reactions

The new east wing galleries officially opened on June 25, 1963. According to the press release, “the new exhibit features in colorful and dramatic settings more than 24 skeletons and skulls of the largest land animals the world has ever known.” The exhibits were officially unveiled with a late afternoon ceremony, in which Carol Hotton (Nicholas Hotton’s daughter) cut the ribbon and the lights to Hall 2 were suddenly turned on to dramatic effect.

Unfortunately, the new exhibits were not universally loved by the museum staff. The wing had been planned a set of compartmentalized exhibits, each corresponding to a subdivision of the Division of Paleontology, with a different curator taking responsibility for each hall. While seeming sensible on paper, this plan turned out to be a logistical nightmare, and a common cause for complaint among Division staff for the next decade. In addition, Gazin in particular voiced concerns as early as January 1964 that the design of the new halls was entirely inadequate for preventing accidental or deliberate damage to specimens by visitors. The mounts in Hall 2 were raised only about a foot off the ground, and were not protected by any sort of guard rail or barrier. As a result, within a few months of the exhibit’s unveiling, several ribs and vertebral processes had been broken off or stolen from CamarasaurusGorgosaurus, Ceratosaurus and others.

With the notable caveat that I never saw the 1963 exhibits in person, I would say that this is aesthetically my least favorite iteration of the east wing. The grandiose, institutional Greco-Roman architecture originally displayed in the Hall of Extinct Monsters was replaced with what can only be described as extremely 1960s design. Solid earth-tone colors, wood paneling and wall-to-wall carpeting gave the halls a much more austere character. While the efforts to categorize specimens into thematic zones was commendable for a museum of that era, the label copy (written by the curators) was still highly pedantic and verbose. As such, the 1963 fossil halls seem to have been very much of their time. While the designers were working to avoid the overt religiosity and grandeur of turn of the century museums, they had not yet reached the point of developing truly audience-centered educational experiences. The result was an exhibit that was humble, yet still largely inacessible. Perhaps for this reason, the 1963 fossil halls were the shortest-lived at NMNH to date, being replaced within 20 years of their debut.

This post was updated and edited on January 8, 2018.

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Extinct Monsters: Murals and Dioramas

Click here to start the Extinct Monsters series from the beginning.

Fossils are the hard evidence behind paleontology. They tell us not only that prehistoric organisms existed, but hold clues as to how they lived and behaved. However, it is only through  artwork that extinct animals and ecosystems can be brought back to life. Since Benjamin Waterhouse Hawkins built the first life-sized dinosaur sculptures in 1842, skilled artists have played a critical role in visualizing the results of paleontological research and making that information available to a wider audience.

At the National Museum of Natural History, spectacular works of art have always appeared alongside displays of original fossils, firing up the viewer’s imagination and inviting them to visualize the world of prehistory. Although many of these pieces are now scientifically dated, they were on the cutting edge in their time. These artworks remain exquisite works of craftsmanship, invaluable for their decades of contribution to science education.

The Life-Sized Models

The charmingly ugly Stegosaurus pictured above is one of the oldest fixtures of the Smithsonian fossil exhibits. F.A.L. Richardson created this model for the the Smithsonian’s exhibition at the St. Louis, Missouri World’s Fair in 1904. Made from papier mâché with a foam skin, the Stegosaurus was based on small sculpture produced by Charles Gilmore. With its sagging belly, sprawling forelimbs, and head held well below the horizontal plane, this Stegosaurus is typical of reconstructions from the early to mid 20th century.

As legend had it, the paper used to fabricate the Stegosaurus was ground-up money from the National Treasury. The model had even earned the nickname “Mr. Moneybags” among some of the museum staff. Curator Emeritus Ray Rye got to the bottom of this in 1981. He contacted the Treasury to find out what was done with worn-out paper money at the turn of the century – apparently it was burned at a plant in Maryland. Nevertheless, at Rye’s request a group of historians from the Treasury took a sample of the Stegosaurus while the hall was closed for construction, and confirmed that it was made from regular paper.

This pudgy papier mache Stegosaurus has been a fixture at the Smithsonian since 1904.

This pudgy Stegosaurus has been a fixture at the Smithsonian since 1904. Photo courtesy of the Smithsonian Institution Archives.

When the Hall of Extinct Monsters opened in 1910, the Stegosaurus was given a spot of honor right in the center of the room. In 1913, a real Stegosaurus skeleton was placed alongside it. Both dinosaurs would remain in place until the exhibit was renovated in 1963. In the reconfigured and renamed Hall of Fossil Reptiles, the model Stegosaurus was relocated to a corner display.  Most recently, the 1981 renovation saw the Stegosaurus model moved to the south side of the gallery, protected by a low plexiglass barrier. This time, it was given a cycad replica for company, and a mural of lush Jurassic jungle behind it. The Stegosaurus remained in this position until the fossil halls closed in 2014.

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The NMNH exhibits team with their nearly-finished Quetzalcoatlus. Image from Thomson 1985.

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The Quetzalcoatlus survived a 2010 earthquake, although the plaster molding above it was damaged. Photo by the author.

The 1981 renovation also saw the introduction of a life-sized model of the pterosaur Quetzalcoatlus. Having been discovered in 1971, the largest flying animal that ever lived was big news at that time. In-house modelmakers spent two years on the project, first sculpting the animal in clay, then casting it in lightweight fiberglass with a steel armature. Paleontologist Nicholas Hotton served as the scientific consultant. Although he was dubious that pterosaurs had any sort of soft body covering, he okayed the use of deer fur to give the model believable texture. However, Hotton nixed the idea of placing a dangling fish in the mouth of the Quetzalcoatlus. Contemporary wisdom was that even giant pterosaurs were extremely light, weighing as little as 75 pounds, so even a 5-pound fish was thought to be enough to disrupt a Quetzalcoatlus in flight.

The Stegosaurus and Quetzalcoatlus both now reside at the Museum of the Earth in Ithaca, New York.

The Murals

The first dedicated prehistoric mammal exhibit at NMNH opened in the summer of 1961. Alongside the array of Cenozoic fossil mounts, the exhibit featured six brand new murals created by paleoartist Jay Matternes. Still active today, Matternes is a prolific artist of both modern and prehistoric wildlife. In addition to the NMNH murals, Matternes has contributed to exhibits at the American Museum of Natural History and the Cleveland Museum of Natural History, as well as numerous publications including National Geographic Magazine. For more of his work, you can check out his website  or the substantial gallery assembled at Agathaumas.

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Matternes’ Oligocene mural as first exhibited in the 1960s. Photo courtesy of the Smithsonian Institution Archives.

The Eocene section in the current Mammals in the Limelight exhibit, featuring mural by Jay Matternes. Photo by author.

The Eocene section in the  Mammals in the Limelight exhibit, featuring a mural by Jay Matternes. Photo by the author.

Each of the murals Matternes contributed to the exhibit depicts North America during an epoch of the Cenozoic, and is displayed behind corresponding fossil mounts. Most of the animals on display coincide with life reconstructions in the murals, so visitors can match the skeletons to images of how they may have looked in life. Matternes’ hyper-detailed style is particularly striking. The environments look nearly photo-real, and not too far removed from the world today. Likewise, the artist’s knowledge of anatomy plainly shows in the utterly lifelike appearances of the animals. I particularly like Matternes’ use of familiar color patterns on the relatives of modern taxa. The Pliocene and Pleistocene murals will be returning in 2019.

Cenozoic

The Cenozoic section of Kish’s 130-foot magnum opus. Source

The “Life in the Ancient Seas” exhibit debuted in 1990 with a monumental 130-foot mural by Eleanor Kish. From the explosion of invertebrate diversity in the Cambrian to the proliferation of aquatic mammals in the recent past, the mural spans 541 years of deep time. The project took Kish two years to complete and is, simply put, a masterpiece. Within the exhibit, this meticulously crafted image defines the space’s layout and color palate. It visually separates concepts and themes, and even directs visitor traffic with it’s strong leftward momentum. But Life in the Ancient Seas is the rare piece that was designed for a particular space, yet still holds up as a beautiful work of art on its own terms.

The Dioramas

My personal favorite part of the NMNH fossil galleries are the dinosaur dioramas. Norman Neal Deaton created three dioramas, representing North America during the Triassic, Jurassic, and Cretaceous. The Mesozoic dioramas were commissioned for the 1963 exhibit renovation, and were on display until 2014. Each 1″:1′ scale diorama is set into a recessed space in the wall and is protected by glass.  The scenes are populated by a menagerie of outdated but gorgeously detailed dinosaurs and contemporary reptiles, set among dense forests of ferns and craggy rock formations. The complexity of the dioramas allows viewers to get lost in them as their eye wanders from one static encounter to the next. I’ve been admiring these scenes since literally before I could talk and I still notice minute details I hadn’t seen before.

The diorama project began in 1963 and took four years to complete. The scenes were initially blocked out by Jay Matternes and Nicholas Hotton, the Curator of Vertebrate Paleontology at the time. Matternes and Hotton worked together on anatomical drawings for each of the animals to be reconstructed, and planned the basic layout of the dioramas. Deaton created the final dioramas at his studio in Newton, Iowa. Deaton had been previously employed at the Smithsonian as an exhibits specialist, but had left to found his own studio in the late 1950s, where he continued to work on projects for the Smithsonian as a contractor. In addition to the dinosaur dioramas, Deaton led the creation of the iconic Fénykövi elephant that stands in the NMNH rotunda today, and has created sculptures and dioramas for dozens of other museums. Deaton is still active today, and much of his 2-D and 3-D work can be seen at his website.

Deaton mailed these slides of his unpainted models to Hotton for approval. Photos courtesy of the Smithsonian Institution Archives.

Deaton mailed these slides of his unpainted models to Hotton for approval. Photos courtesy of the Smithsonian Institution Archives.

Deaton sculpted each of the animals in clay based on the drawings provided by Matternes and Hotton. Nearly every model went through a few incremental adjustments based on notes from Hotton, changing things like the bulk of the muscles or how visible the scapula or pelvis would be under the skin. The soft anatomy was based on modern reptiles, particularly crocodiles, although Deaton found that some of the animals had no obvious analogs. Once the clay models were approved, they were casted in rubber, then painted. Deaton also created the miniature worlds inhabited by the animals, including foliage, muddy riverbanks, and sheer cliffs. The backdrops, however, were painted by Matternes.

The completed dioramas represented the most up-to-date knowledge of the Mesozoic world at that time. Of course, our understanding of dinosaurs has been overhauled significantly since then. Compared to the active, fleet-footed, and often feathered dinosaurs we know today, the inhabitants of the NMNH dioramas at first look a bit ponderous and inert. Inaccuracies are easy to point out: the Ankylosaurus has a weird clubless armadillo tail, the torso of the Diplodocus is much too long, the Cretaceous diorama mixes Hell Creek and Judith River dinosaurs that were separated by at least 20 million years, and there are sprawly tail-draggers aplenty.

Cretaceous diorama by Norman Deaton. Source: flickr.

Cretaceous diorama by Norman Deaton. Photo by the author.

Triassic diorama

Triassic diorama by Norman Deaton. Source

Still, these issues are easy to overlook when one appreciates just how engaging these scenes are. Little details like footprints behind each animal and mud splattered on their feet fill the motionless dioramas with life and the possibility of more adventures in the imagination of the viewer. And several of the models are surprisingly energetic for 60’s dinosaurs. The Ceratosaurus face-biting the Camptosaurus (above) is full of energy, and the Elphrosaurus  is running full-tilt with its tail in the air (and even has propatagia for some reason!).

Many of the works of art in the NMNH fossil halls are no longer appropriate as literal representations of prehistoric animals. But that does not mean they are irrelevant relics of mid-century science. Each model and painting is a stunning example of artistry, and more to the point, every inaccuracy is an opportunity to start up a conversation about what we know about prehistory and how we know it. These pieces are time capsules in the history of science, representing different eras of understanding and the researchers that took part in them. I, for one, would hate to see them forgotten.

A big thank you  to Norman Deaton and Raymond Rye for their assistance with this article!

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Extinct Monsters: The Marsh Dinosaurs, Part II

Read the Marsh Dinosaurs, Part I or start the Extinct Monsters series from the beginning.

During the first decade of the 20th century, the United States National Museum paleontology department was located in an offsite building in northwest Washington, DC. It was here that preparators Charles Gilmore, Norman Boss, and James Gidley slowly but surely worked through the literal trainloads of fossil specimens O.C. Marsh had acquired for the United States Geological Survey. The Marsh Collection included unknown thousands of specimens, many of them holotypes, and there was no shortage of gorgeous display-caliber material. Even after the “condemnation of worthless material” Gilmore and his team quickly filled the available exhibit space in the Arts and Industries Building with mounted skeletons.

The Ceratosaurus

With no more display space and plenty more fossils, it was fortunate that the USNM moved to a new, larger building in 1910. In this iconic, green-domed building (now the National Museum of Natural History), the paleontology department received newly furnished collections spaces and the entire east wing to fill with display specimens. The evocatively titled Hall of Extinct Monsters provided a new home for the mounted skeletons already constructed for the old exhibit, as well as plenty of room for new displays.

The Ceratosaurus nasicornis holotype was originally housed in a glass case. Image courtesy of the Linda Hall Library.

Ceratosaurus. Photo by the author.

The delicate arms of Ceratosaurus were removed several years prior to the hall’s closing. Photo by the author.

One of the first new additions was the type specimen of Ceratosaurus nasicornis (USNM 4735), mounted in relief. Marshall Felch led the excavation of this specimen in 1883 at a quarry near Cañon City, Colorado. The nearly complete skeleton received a cursory description from Marsh upon its discovery, but it was Gilmore who described it properly in 1920, ten years after it was put on display. When it was introduced to the Hall of Extinct Monsters, this was the only Ceratosaurus specimen yet found, making the mount a USNM exclusive. The skeleton was originally displayed in a glass case, but during the 1963 renovation it was placed in a more open setting.

Even today, Ceratosaurus is only known from a handful of specimens. For this reason, the original Ceratosaurus fossils will not be returning when the current renovation is completed in 2019. The new hall will instead feature a three-dimensional, standing cast of this skeleton. The original fossils are now in the museum’s collections, available for proper study for the first time in over a century.

The Camptosaurus

In 1912, two mounted skeletons of Camptosaurus, one large (USNM 4282) and one small (USNM 2210), were introduced to the Hall of Extinct Monsters. William Read excavated both specimens at Quarry 13 in the Como region of Wyoming a quarter of a century earlier. Representing the first-ever mounted skeletons of Camptosaurus, these specimens have had a rather complex taxonomical history. Marsh initially described both specimens as Camptosaurus nanus, a new species within the genus Camptosaurus (the type species was Camptosaurus dispar, also coined by Marsh). After the fossils were acquired by the USNM, Gilmore re-described the larger individual as a new species, Camptosaurus browni. This designation remained until the 1980s, when Peter Galton and H.P. Powell determined that C. nanus and C. browni were actually both growth stages of C. dispar.

Regardless of what they are called, both specimens were remarkably well-preserved and reasonably complete. Most of the skeletal elements of the larger Camptosaurus came from a single individual that was found articulated in situ. However, some of the cervical vertebrae came from another specimen from the same quarry, and the skull, pubis, and some of the ribs were reconstructed. Of particular interest is the right ilium, which has been punctured all the way through by a force delivered from above. Gilmore postulated that “the position of the wounds suggest…that this individual was a female who might have received the injuries during copulation.” The smaller “C. nanus” was also found mostly complete, but two metatarsals came from a different individual and the skull and left forelimb were sculpted.

The original pair of Camptosaurus mounts. Image from Backyard Dinosaurs.

Gilmore supervised the creation of both mounts, and constructed the larger individual himself. Norman Boss took the lead on the smaller specimen. As with the other dinosaur skeletons, the mount was centered on an inch-thick steel rod bent to conform to the shape of the vertebral column. Bolts were drilled directly into the vertebrae to attach them to the armature, and the vertebral foramina were filled with liberal amounts of plaster to secure them to the rod. A similar process was used to assemble each of the limbs, and the ribs were supported by a wire cage.

Gilmore aimed to correct many specifics of Marsh’s  original illustrated reconstruction of Camptosaurus. To start, he shortened the presacral region to make a more compact torso. Marsh had also inexplicably illustrated Camptosaurus with lumbar vertebrae (a characteristic exclusive to mammals), which Gilmore corrected. Finally, Marsh had reconstructed the animal as an obligate biped, but Gilmore  determined that “Camptosaurus used the quadrupedal mode of progression more frequently than any other known member of Ornithopoda.” Accordingly, the larger Camptosaurus mount was posed on all fours. The completed Camptosaurus mounts were placed together in a freestanding glass case toward the rear of the Hall of Extinct Monsters. In 1962 the pair was moved to the left of the Diplodocus on the central pedestal of the redesigned exhibit. During the 1981 renovation they were moved a few feet back, so that they were alongside the sauropod’s tail.

This cast replaced the original Camptosaurus mount in 2010. Photo by the author.

This cast replaced the original Camptosaurus mounts in 2010. Photo by the author.

The retired plaster skulls of the original Camptosaurus mounts. Photo by the author.

The retired plaster skulls of the original Camptosaurus mounts. Photo by the author.

Both Camptosaurus skeletons taken off exhibit in 2010 and replaced with a cast of the adult. The delicate fossils, which had suffered from considerable wear and tear over the past hundred years, were stabilized and stored individually for their protection. The new mount has a number of upgrades to reflect our improved understanding of dinosaur anatomy. The arms are closer together and the palms face inward, because the pronated (palms down) hands on Gilmore’s version have been determined to be a physical impossibility. The new mount also features a completely different skull. The rectangular model skull used on the original mount was based on Iguanodon, but new discoveries show that the skull of Camptosaurus was more triangular in shape. Both the adult and juvenile Camptosaurus will appear in the new National Fossil Hall.

The Stegosaurus

The Smithsonian’s first Stegosaurus exhibit was a life-sized model built for the 1904 World’s Fair in St. Louis. This model found its way into the Hall of Extinct Monsters in 1910. In 1913, the model was joined by a mounted Stegosaurus skeleton found at the same Cañon City quarry as the Ceratosaurus. A third Stegosaurus, the holotype of S. stenops, was introduced in 1918. Lovingly called the “roadkill” Stegosaurus, USNM 4934 is remarkable in part because it was found completely articulated. In fact, before its 1886 discovery by Marshall Felch, it was unknown exactly how the animal’s plates were positioned on its back.

Standing Stegosaurus mount and life-size model, circa 1950. Photo courtesy of the Smithsonian Institution Archives.

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Stegosaurus model, standing mount, and “roadkill” on display in the Hall of Extinct Monsters. Source

All three Stegosaurus displays were moved in 1963 and 1981. In Fossils: The History of Life, the Stegosaurus skeletons were positioned flanking the Diplodocus in the central display area, with the standing mount on the right and the roadkill skeleton on the left. The model Stegosaurus stood opposite the mount. Just like the Triceratops and Camptosaurus, many decades on display took their toll on the standing Stegosaurus, so in 2003 the fossils were removed from the exhibit. Dismantling the Stegosaurus was particularly challenging because of the large amount of plaster applied by the mount’s creators. In some cases the plaster infill had to be removed with hand tools, which put further pressure on the fossils. Additionally, the rod supporting the backbone had been threaded right through each of the vertebrae, and was extremely difficult to remove. A casted Stegosaurus mount in a more active pose was returned to the exhibit in 2004.

Cast of Stegosaurus and Camptosaurus. Photo by the author.

Casts of Stegosaurus and Camptosaurus. Photo by the author.

Roadkill stego

“Roadkill” Stegosaurus in 2014. Photo by the author.

After 110 years on display at the Smithsonian, the model Stegosaurus has been donated to the Museum of the Earth in Ithaca. The roadkill Stegosaurus, however, will feature prominently in the new National Fossil Hall, mounted upright on the wall by the exhibit’s secondary entrance. The 2004 Stegosaurus cast had a number of anatomical issues and will not be returning – instead, it will be replaced by an updated cast made from the same original fossils.

The Marsh dinosaurs have been of critical importance in our understanding of the Mesozoic world, but at this point these fossils are historic artifacts as well. When they were uncovered, the American civil war was still a recent memory, and railroads had only recently extended to the western United States. Before the first world war they had been assembled into mounts, and for more than a century these fossils have been mesmerizing and inspiring millions of visitors. Several of these mounts, including the Triceratops, Ceratosaurus and Camptosaurus, were the first reconstructions of these species to ever appear in the public realm, and therefore defined popular interpretations that have lasted for generations. Some visitors may lament that many of the original specimens have been recently been replaced with replicas, but the fact is that these are irreplaceable and invaluable national treasures. They inform us of our culture, and our dedication to expanding knowledge and our rich natural history. We only get one chance with these fossils, and that is why the absolute best care must be taken to preserve them for future generations.

References

Gilmore, C.W. 1912 “The Mounted Skeletons of Camptosaurus in the United States National Musuem.” Proceedings of the US National Museum 14:1878.

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.

Jabo, S. 2012. Personal communication.

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Filed under collections, dinosaurs, exhibits, Extinct Monsters, field work, fossil mounts, history of science, museums, NMNH, ornithopods, reptiles, theropods, thyreophorans