Tag Archives: history of science

The Hidden Rhomaleosaurus

Rhomaleosaurus cast at the NMNH Museum Support Center.

Rhomaleosaurus cast at the NMNH Museum Support Center. Source

Residing upon the wall of the Smithsonian’s Museum Support Center (MSC) in Suitland, Maryland is the skeleton of a giant prehistoric reptile. This is a cast of Rhomaleosaurus cramptoni, a short-necked plesiosaur from the early Jurassic rocks of England’s westeast coast. With broad jaws bristling with teeth and a length exceeding 22 feet, this specimen would surely be a crowd pleaser, and yet it has never been on display at the National Museum of Natural History. Since the MSC opened in 1983, only staff, visiting scientists, and gaggles of interns have seen it.

The original fossil from which the Smithsonian cast was taken came from an alunite mine on the Yorkshire coast. Miners unearthed the nearly  complete Rhomaleosaurus in 1848. This was a year after Mary Anning‘s death, and plesiosaurs were already well known to British naturalists. The new specimen was uncommonly large, however, and the mine’s owner, George Augustus Phipps, displayed it with pride at his residence. Five years later, Phipps gifted the skeleton to his friend Phillip Crampton, an Irish anatomist. Crampton arranged for the plesiosaur to be displayed at the 1853 meeting of the British Association for the Advancement of Science, held in Dublin.

Illustration

Illustration of the Rhomaleosaurus cast for sale from Henry Ward’s 1866 catalog.

For nearly a decade, the skeleton remained in a semi-permanent tent that had been erected for the meeting. Eventually, increasing concern that the tent structure was not protecting the fossil from the elements led to the specimen’s conditional relocation to the Royal Dublin Society Museum. It was here that Alexander Carte and William Baily published the first – albeit brief – description of the Yorkshire plesiosaur, naming it Plesiosaurus cramptoni (Harry Seely moved it to the genus Rhomaleosaurus in 1874).

Around the same time that Carte and Baily were preparing their description, the Rhomaleosaurus received another fateful visitor. This was Henry Ward of Rochester, New York, founder of Ward’s Scientific Company. At the time, Ward was a well-known and well-regarded fossil and mineral dealer. Ward first traveled to Europe in 1854 at the age of 20. He continued to venture around the world collecting geological specimens, which he sold to fund his degree at the Paris School of Mines. Ward’s timing was excellent, and the connections he made during his studies put him in an ideal position to start a company supplying specimens to the new natural history museums that were springing up on both sides of the Atlantic. Ward was also permitted to take casts of museum specimens, apparently including the Rhomaleosaurus in Dublin.

Starting in 1866, the Ward Scientific Company catalog offered a plaster cast of “Plesiosaurus” cramptoni for sale. Described as the largest plesiosaur ever discovered, the fully painted cast was listed at $150, which would be a little over $4000 today. The skull or left fore-flipper could be had for $15 and $10, respectively.

Rhomaleosaurus cast at the London Museum of Natural History.

Rhomaleosaurus cast at the Museum of Natural History in London. Source

It is unknown how many Rhomaleosaurus casts Ward sold, but five survive today. In addition to the Smithsonian copy, casts are held by Cornell University, the University of Illinois, the Bath Royal Literary and Scientific Institute, and the Natural History Museum in London. Each of these casts varies slightly from the others. While the Smithsonian Rhomaleosaurus closely matches the catalog illustration (missing left flipper and all), the Bath version has duplicate front and back flippers, which means that they are backwards on one side. Meanwhile, all four flippers on the London cast are sculpted replacements.

Most of the Rhomaleosaurus casts are tucked away in geology departments or seminar rooms where they are not often seen by the public. The London copy is an exception, however. The Rhomaleosaurus holds court in the Fossil Marine Reptiles gallery, where it is the largest specimen on display. In fact, it may well be the second most-photographed object in the museum, after Dippy the Diplodocus. Somewhat anachronistically, the London Rhomaleosaurus is displayed with a placard about Mary Anning, even though it is one of the few specimens in the gallery she didn’t discover.

USNM prep lab 1913

USNM fossil preparation lab in 1913. Photo courtesy of the Smithsonian Institution Archives.

The Smithsonian’s Rhomaleosaurus cast was purchased from Ward’s Scientific Company in 1895, when the United States National Museum was still operating out of the Arts and Industries building. Surprisingly, the cast is not on Curator Charles Gilmore’s list of display specimens, either in the old Arts and Industries exhibit or in the new USNM building that opened in 1910. Although the Department of Paleontology prepared exhibits for the 1896 International Exposition in Atlanta and the 1898 Trans-Mississippi Exposition in Omaha, the Rhomaleosaurus was not featured in either. Indeed, the plesiosaur can only be seen in historic photographs of the fossil preparation lab. From these, we can determine that the Rhomaleosaurus adorned the wall of this space as early as 1913 and as late as 1926. The cast was not part of any of the mid-century modifications to the paleontology exhibits, and was eventually relegated to MSC in 1983. It is still intact, but its existence is not widely known, even to paleontologists.

Sadly, the original Rhomaleosaurus fossils have not fared as well as the casts. In 1877, the Royal Dublin Society Museum was incorporated into the National Museum of Ireland, at which time the institution gained permanent ownership of the specimen. During a move in the 1920s, the Rhomaleosaurus was broken up with sledgehammers for ease of transport. Afterwards, the pieces were scattered throughout the collections for decades. Adam Smith has been instrumental in reuniting and restoring this historic skeleton (video of the pieces here). It was a principal subject of his 2007 doctoral thesis, and he oversaw the complete, three-dimensional preparation of the original skull. Currently, there are long-term plans to reassemble and display the Rhomaleosaurus at the National Museum of Ireland.

Hall overview

Overview artwork of the National Fossil Hall, on display in “Last American Dinosaurs” at NMNH. Note Rhomaleosaurus in the upper left, behind the Jurassic platform.

Back in the United States, the Smithsonian’s Rhomaleosaurus cast will finally go on exhibit in 2019. It will be featured in the new National Fossil Hall, mounted on the south wall of hall 4 (roughly where the café used to be – see the upper left of the image above). It seems that 168 years after its discovery, this Yorkshire plesiosaur is poised to re-enter the realm of public display on both sides of the Atlantic.

References

Smith, A. 2006. Dublin’s Jurassic “Sea-Dragon.” Geoscience 17: 26-27. http://plesiosauria.com/pdf/Smith_2006_Dublin_seadragon.pdf

Smith, A.S. 2007. Anatomy and Systematics of the Rhomaleosauridae (Sauropterygia: Plesiosauria). PhD thesis. School of Biology and Environmental Science, University College Dublin.

Smith, A.S. and Dyke, G.J. 2008. The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics. Naturwissenschaften 95: 975-980.

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.

Ward, H.A. 1866. Catalog of Casts and Fossils From the Principle Museums of Europe and America with Short Descriptions and Illustrations. Rochester, NY: Benton and Andrews.

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Filed under exhibits, fossil mounts, history of science, museums, NHM, reptiles

Was the Hawkins Hadrosaurus real?

Photo from Weishampel and Young 1996.

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

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

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

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

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

courtesy

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

Courtesy

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

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

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

Hawkin's studio

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

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

References

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

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

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

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Filed under dinosaurs, fossil mounts, history of science, museums, ornithopods

Beecher’s “Claosaurus”

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

Edmontosaurus is surprisingly modern

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

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

The Hawkins Hadrosarus and Dollo Iguanodon. Photos from

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

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

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

woo

Beecher’s Edmontosaurus, ca. 1917. Source

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

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

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

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

In the great hall of dinosaurs

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

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

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

References

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

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

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

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Filed under dinosaurs, fossil mounts, history of science, museums, ornithopods, PMNH, reptiles

AMNH 5027 at 100

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

Photo by the author.

AMNH 5027 in November 2015. Photo by the author.

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

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

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

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

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

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

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

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

Image courtesy of the AMNH Archives.

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

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

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

finished mount, room under construction

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

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

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

References

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

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

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

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

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

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

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

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

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

Triceratops at the Natural History Museum, London.

Triceratops at the Natural History Museum, London. Source

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

Pan American exhibition

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

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

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

St. Louis Expo

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

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

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

tweet

Hey, that looks familiar! Source

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

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

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

Hmm

Did I speak too soon? Source

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

References

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

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

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

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

A Trio of Tyrants

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

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

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

Gorgosaurus at AMNH

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

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

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

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

Gorgosaurus libratus – USNM 12814

gorgo

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

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

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

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

Gorgosaurus sp. – AMNH 5458

albertosaurus

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

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

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

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

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

Gorgosaurus sternbergi” – AMNH 5664

gorgo sternbergi

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

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

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

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

AMNH 5027 was restored and remounted in 1995.

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

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

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

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

References

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

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

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

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

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

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

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

Permo-Triassic Synapsids at NMNH

Click here to start the NMNH series from the beginning.

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 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 had been 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 were 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.

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 1970s, 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

“Daptocephalus” as exhibited after 1981. Source

Photo by Christian Kammerer

Close up of the erroneously reconstructed skull. Photo by Christian Kammerer.

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 badly damaged skull to resemble more complete Daplocephalus specimens, and added casts of Daplocephalus limbs. As it turns out, however, USNM 299749 is not a Daplocephalus – it is a somewhat distantly related dicynodont currently called Odontocyclops (also subject to change). 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” has been mislabeled and erroneously reconstructed for many years, but the current renovation of the NMNH fossil halls now presents an opportunity to deconstruct the specimen and study it up close.

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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Filed under exhibits, Extinct Monsters, field work, fossil mounts, history of science, mammals, museums, NMNH