Category Archives: field work

June 8, 2015 · 3:48 pm

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).

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

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

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

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.

3 Comments

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

Tagged as Barnum Brown, C.H. Sternberg, dinosaurs, fossil mounts, history of science, museums, natural history museums, NMNH, paleontology, Smithsonian

April 28, 2015 · 3:06 pm

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 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.

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

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 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.

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.

4 Comments

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

Tagged as evolution, fossil mounts, history of science, museums, natural history museums, paleontology, Smithsonian, synapsids

April 23, 2015 · 12:06 pm

Fossil sandboxes are terrible

Are these kids learning yet? Source

Today, I need to take a moment to rail against one of the most reliably entertaining and beloved of museum attractions – fossil sandboxes. These activities are nearly ubiquitous at paleontology-related parks and museums, and some of them can be quite large and elaborate. There are a few variations, but they generally involve children using simple hand tools to dig through sand or loose gravel to uncover planted fossils (usually replicas, but I’ve seen a few places sacrifice real Pleistocene bones for this activity). Kids and families absolutely adore fossil sandboxes, and they generate all kinds of goodwill for the museums that feature them. In fact, many visitors have come to expect sandbox digs at paleontology exhibits, and become annoyed when one isn’t available.

I understand the appeal of sandboxes. For kids, they’re an opportunity to play pretend, engage in a physical activity after a day of looking at stuff, and generally have fun making a mess. Museum educators, myself included, are all about Gardner’s theory of multiple intelligences – the idea that different people learn best in different ways. While some easily absorb and retain information by reading or listening quietly, others prefer to solve a problem, talk through a topic with others, or engage in some sort of hands-on activity. That last one is called bodily-kinesthetic intelligence, and it is common among athletes and actors, among others. A fossil sandbox allegedly provides an activity for bodily-kinesthetic learners to develop and hone a physical skill related to the topic at hand. Kids get a chance to see and feel what it’s like to be a real paleontologist working in the field.

Except not really. A sandbox focuses kids’ attention, but that’s not the same thing as learning. What they’re doing has virtually nothing to do with actual paleontology. Digging is a comparatively minor part of field work – far more time is spent prospecting for fossils. When a team does start excavating, it’s conducted in a precise and organized manner, so that no taphonomic data is lost. By comparison, the sandbox arrangement conjures ideas of frantic treasure hunting, rather than piecing together and interpreting clues about past life. Furthermore, digging through loose sand is exceedingly rare in the field. If it were so easy to get at fossils, they would either have been found already or would have eroded away to nothing. A simulation is supposed to model a real event, or constrain that event to a limited set of variables. Sandbox digs do neither. Parents and caretakers might appreciate a place where kids can entertain themselves for a while, and educators can pat themselves on the back for providing a physically-involved experience. But there’s no use pretending that anybody is learning in what amounts to a themed playpen.

One alternative to the sandbox concept is provided by Thistle. He describes an activity in which he sets up a series of square meter “dig sites” within a room. Different specimens or artifacts are placed in each square. Participating students are then told that each square represents what was found in a layer of excavation, and are prompted to draw conclusions based on the different objects recovered from different strata. Students consider the spatial relationships among found objects, and discuss the roles of taphonomy and deep time. Unlike a sandbox dig, the results of this activity are comparable to those of a real excavation, and students are asking the same sorts of questions paleontologists would. Granted, Thistle’s activity requires much more guidance than a sandbox, but it’s a good example of something that participants might actually learn from.

The point is, we owe our audiences more than a mindless diversion with no bearing on actual science. And for that matter, we owe the scientists whose work we’re communicating more than a tacky, inaccurate simulation. If our goals are to inspire enthusiasm for science and to encourage young visitors to think scientifically, surely we can do better than a sandbox dig.

References

Thistle, P.C. 2012. Archaeology Excavation Simulation: Correcting the Emphasis. Journal of Museum Education 37:2:65-76.

6 Comments

Filed under education, exhibits, field work, museums, opinion, science communication

Tagged as exhibits, fossils, museums, science communication, science education

March 11, 2015 · 8:43 pm

The Carnegie Quarry Diaspora

About 150 million years ago, a severe drought ravaged the western interior of North America. In eastern Utah, malnourished dinosaurs gathered near a dwindling river. Unwilling or unable to leave the water source, they eventually died of thirst or disease. When rain finally returned to the region, three or four successive flash floods washed dozens of animal carcasses into a relatively small depositional area to the southeast. Today, this site is known as the Carnegie Quarry at Dinosaur National Monument, and it is one of the most incredible fossil sites in the world.

Dinosaur National Monument interns collect data on the quarry wall. Source

Today, a structure encompassing a 180-foot section of the deposit (less than half its total length) allows visitors to view nearly 1400 dinosaur bones in situ. However, the fossils on display at Dinosaur National Monument represent only a portion of the material found at the Carnegie Quarry. Between the site’s discovery in 1908 and the establishment of the quarry wall exhibit, more than 20 reasonably complete dinosaur skeletons and dozens more incomplete specimens were excavated and distributed to museums in the US and Canada. No less than eleven mounted skeletons have been created from this material, and they are all still on display today. Although they are thousands of miles from their place of discovery and exhibited in four different cities, these mounts all represent individuals that lived and died in the same environment. They may have even encountered each other in life!

The Discovery

Earl Douglass was already an established fossil hunter when the Carnegie Museum of Natural History hired him in 1902. Late in the 1909 field season, Douglass was prospecting near the confluence of the Green and Yampa Rivers when he spotted a series of sauropod vertebrae eroding out of the rocks. Once Douglass and his crew began excavating the fossils, it became apparent that they had not just one remarkably complete dinosaur, but several. Douglass called it a “beautiful sight,” and CMNH director William Holland could barely contain his glee in his reports back to the Pittsburgh museum. Under Douglass’s management, CMNH crews worked at what became known as the Carnegie Quarry for 13 years. The dinosaur fossils were jumbled and often overlaid one another, so the excavators had to work on multiple skeletons simultaneously. The especially hard sandstone also slowed their work, and the team regularly resorted to huge horse-drawn plows and even dynamite to reach the fossils. Eventually railway tracks were installed to help transport blocks of sandstone out of the quarry.

In 1915, Holland successfully petitioned Woodrow Wilson to preserve the site as a national monument. CMNH crews continued to excavate until early 1923. At that point, their primary benefactor Andrew Carnegie had died, and funding for field work was dwindling. Other museums collected from the quarry periodically in the years that followed, but Douglass’s idea to contain the remaining fossils in an on-site museum was not realized until 1958.

The Mounts

CMNH Apatosaurus. Historic photo from McGinnis 1982; modern photo source.

Apatosaurus louisae – CM 3018

The CMNH Apatosaurus was the first dinosaur discovered at the Carnegie Quarry. After Douglass first spotted the articulated caudal vertebrae in August of 1909, his crew spent several months extracting the rest of the skeleton from the rocks. The excavation continued into early 1910, and by the time they were finished they had the most complete Apatosaurus ever found – a title the specimen holds to this day. Holland mounted the 77-foot skeleton alongside the museum’s Diplodocus in just three years, at the time a record for a sauropod mount.

Holland famously left his Apatosaurus headless for decades due to a disagreement with Henry Osborn of the American Museum of Natural History. Douglass recovered a skull that almost certainly belonged to the Apatosaurus, but Holland opted not to use it because it contradicted the sculpted head already in place on the AMNH Apatosaurus mount. After Holland’s death in 1932, museum staff quietly added a casted Camarasaurus skull as a placeholder. This was finally replaced with a proper Apatosaurus skull in 1979. More recently, the team at Phil Fraley Productions disassembled and restored the Apatosaurus, along with the rest of the classic CMNH dinosaurs. Since 2007, this specimen has been back on display in a more graceful modern pose.

AMNH Barosaurus. Source

Barosaurus lentus – AMNH 6341

When the CMNH team discovered this skeleton in 1912, they assumed it was yet another specimen of the well-known Diplodocus. It was harvested for parts, with portions sent to CMNH, the United States National Museum, and the University of Utah to supplement their displays. When the specimen turned out to be the more obscure sauropod Barosaurus, it languished in pieces for many years. Barnum Brown of AMNH was making a circuit of the fossil collections at various natural history museums when he rediscovered this specimen. Through a series of purchases and trades, the Barosaurus was reunited at AMNH in 1929.

Nevertheless, AMNH quickly abandoned plans to mount the Barosaurus – the museum already had a sauropod on display, and there wasn’t enough floor space for another one. It wouldn’t go on display until 1991, when Lowell Dingus conceived of the idea to mount the Barosaurus in a spectacular rearing pose as part of the renovation of the Theodore Roosevelt Rotunda. Peter May took on the project – one of the first mounts produced by his company Research Casting International. The resulting display, actually a cast, is the tallest free-standing dinosaur mount in the world.

ROM Barosaurus. Source

Barosaurus lentus – ROM 3670

Douglass recovered a second partial Barosaurus skeleton in 1912, which consisted of a mostly complete torso and parts of each leg. It stayed in the CMNH collections for many years, until they traded it to the Royal Ontario Museum in 1962. ROM staff intended to mount the skeleton, but once again this was cancelled due to a lack of space. David Evans was developing a new ROM paleontology exhibit in 2007 when he learned that the museum had most of a Barosaurus sitting in its collections. With only weeks remaining before the exhibit’s opening, Evans tapped Research Casting International to mount the sauropod, supplemented with a replica neck and tail from the AMNH version.

CMNH Allosaurus. Historic photo source; modern photo source.

Allosaurus fragilis – CM 11844

Several Allosaurus specimens are known from the Carnegie Quarry, but the one on display at CMNH is one of the largest. Douglass and his team excavated this 35-foot skeleton between 1913 and 1915. The mount was built in 1938. Although the specimen included a partial skull, the exhibit team swapped it with a cast of a more complete skull (also found in the Carnegie Quarry) from the collections of the University of Utah. This mount also includes casts of the arms of USNM 4734, an Allosaurus collected for O.C. Marsh.

CMNH Stegosaurus. Historic photo source; modern photo source.

Stegosaurus ungulatus – CM 11341

The CMNH Stegosaurus is a composite of several individuals excavated from the Carnegie Quarry between 1920 and 1922. Museum staff completed the 21 foot-long mount in 1940, using a skull cast from USNM 8612. Casts of this skeleton were distributed to several other museums at some point, one of which is on display at the University of Nebraska State Museum. Phil Fraley’s company remounted the CMNH original in 2007.

Carnegie Camarasaurus. Source

Camarasaurus lentus – CM 11338

This juvenile Camarasaurus is the most complete sauropod ever found. It is displayed as a relief mount almost exactly as it was discovered, with two exceptions. The left leg was swapped with a more complete one from another individual, and the tail was re-positioned to create a more aesthetically pleasing mount. Casts of this skeleton are displayed at museums throughout the United States, including Dinosaur National Monument, but the original is at CMNH. ~~This specimen is also notable because its left scapula is preserved in its life position, making it a helpful model for skeletal reconstructions and exhibit mounts.~~

NMNH Camarasaurus. Photo by the author.

Camarasaurus lentus – USNM 13786

The second best Camarasaurus also comes from Carnegie Quarry, but it is a considerably larger individual. Only the tail and a few odds and ends were missing. CMNH kept the specimen for several years before trading it to USNM in 1933 for a set of Pliocene horse skeletons. Norman Boss prepared the specimen in full view of the public during the 1936 Texas Centennial Exposition – one of the first known examples of such an exhibit. The completed mount appeared at USNM in the 1950s, sporting the tail of another Camarasaurus. At over 30 feet long, this skeleton is one of the largest dinosaurs on display at the Smithsonian. Unfortunately, the death pose somewhat limits the effect. The Camarasaurus was taken off exhibit in late 2014 for conservation and remounting. When it returns, it will be standing on its feet for the first time in 150 million years, taking its rightful place as one of the museum’s most impressive dinosaurs.

DMNH Diplodocus. Source

Diplodocus longus – DMNH 1494

Since this Dipldodocus was found somewhat disarticulated, Douglass suggested that the carcass may have been twisted apart while rolling downstream. AMNH held on to this skeleton for some time before trading it to the Denver Museum of Nature and Science in 1936 for two mammoth skeletons. Preparator Phillip Reinheimer mounted the skeleton with the help of 40 workers assigned to the museum through the Works Progress Administration. Additional Diplodocus fossils collected by William DeWeese (actually the first dinosaur specimens acquired by the museum) were also used to complete the mount. The Diplodocus remained on view until 1989, when Ken Carpenter and others restored and remounted the sauropod, elevating its tail and making its neck sweep gracefully to the left. The improved mount has been on display since 1995.

CMNH Camptosaurus. Historic photo from McGinnis 1982; modern photo source.

Camptosaurus aphanoecetes – CM 11337

Douglass found this controversial small ornithopod in 1922, and correctly matched it with an isolated leg several feet away. It was first identified as Camptosaurus medius, but in 2008 Ken Carpenter reassigned it to the new species C. aphanoecetes. A 2011 phylogenic study by Andrew McDonald moved this specimen to a new genus, Uteodon. Carpenter, however, asserts that McDonald’s analysis was based on an incorrectly associated Dryosaurus braincase.

CMNH staff assembled the fossils into a relief mount in 1940. The skull, hindfeet, and tail were all sculpted. During the 2007 renovation, the Phil Fraley Productions team extracted the fossils from the plaster slab, even managing to preserve the delicate ossified dorsal tendons. They then created a new, three-dimensional mount, which features a revised replica skull.

CMNH Dryosaurus. Historic photo from McGinnis 1982; modern photo by the author.

Dryosaurus altus – CM 3392

This Dryosaurus skeleton is the most complete of several collected at Dinosaur National Monument. The tail is missing, and given the completeness of the rest of the skeleton it may well have been destroyed when Douglass’s crew was blasting through rock to get to the bone layer. The Dryosaurus entered the CMNH collections in 1922, and was assembled as a 9 foot-long relief mount in 1940. In 2007, Fraley’s team removed the fossils from the plaster matrix, and just as they did with the Camptosaurus, constructed a standing mount. To date, this is the only mounted Dryosaurus specimen in the world. It is displayed alongside a juvenile Ceratosaurus cast acquired from Western Paleontological Laboratories.

National Museum of Natural History in Washington, DC.

NMNH Diplodocus. Photo by the author.

Diplodocus sp. – USNM 10865

The National Museum of Natural History’s Diplodocus was one of the last articulated skeletons removed from the Carnegie Quarry. When the CMNH crew closed up shop, Charles Gilmore of the Smithsonian moved in to recover one of the sauropod skeletons Douglass left behind. In 1923, Gilmore’s team excavated a partial Diplodocus, and also cherry-picked a few extra bones from an adjacent specimen. The process of mounting the skeleton at USNM took six years of continuous work, and Gilmore would later describe it as the most ambitious undertaking his department hadever attempted. The 70-foot Diplodocus mount was completed in 1931, and remained unchanged for more than 80 years. It was finally taken down in December 2014, and will return in a new pose in 2019.

Addendum: Mike Taylor recently called attention to a gorgeous map of the entire deposit prepared by Ken Carpenter, which was what prompted this post. Check it out here.

References

Carpenter, K. (2013). History, Sedimentology, and Taphonomy of the Carnegie Quarry, Dinosaur National Monument, Utah. Annals of the Carnegie Museum 81:3:153-232.

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

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.

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.

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Filed under AMNH, CMNH, collections, dinosaurs, DMNS, exhibits, field work, fossil mounts, history of science, museums, NMNH, ornithopods, sauropods, theropods, thyreophorans

Tagged as amnh, CMNH, dinosaur national monument, dinosaurs, fossil mounts, fossils, history of science, museums, NMNH, paleontology, ROM

October 30, 2014 · 10:39 am

Bully for Camarasaurus

Note: This post was written in 2014. It predates Emanuel Tschopp and colleagues’ landmark paper which, among other things, resurrected the genus Brontosaurus. I’ve attempted to update the taxonomy where appropriate, but it may still be a bit of a mess.

The story of the mismatched head of Brontosaurus is one of the best known tales from the history of paleontology. I think I first heard it while watching my tattered VHS copy of More Dinosaurs—scientists had mistakenly mounted the skull of Camarasaurus on an Apatosaurus skeleton, and the error went unnoticed for decades. The legend has been repeated countless times, perhaps because we revel in the idea that even experts can make silly mistakes. Nevertheless, I think it’s time we set the record straight: nobody ever mistakenly placed a Camarasaurus skull on Apatosaurus. The truth is a lot more nuanced—and a lot more interesting—than a simple case of mistaken identity.

Intrinsically related to the head-swap story is the replacement of “Brontosaurus” with “Apatosaurus” in the popular lexicon. This is well covered elsewhere, so I’ll be brief. Scientific names for animals are governed by the International Code of Zoological Nomenclature, which includes the principle of priority: if an organism has been given more than one name, the oldest published name is the correct one. Leading 19th century paleontologist O.C. Marsh named Apatosaurus ajax in 1877, based on a vertebral column discovered in the Morrison Formation of Colorado. Two years later, Marsh introduced Brontosaurus excelsus to the world, from a more complete specimen uncovered in rocks of the same age in Wyoming. Like many of Marsh’s publications, these descriptions were extremely brief, offering a scant two paragraphs for each taxon. However, Marsh did provide a longer description of Brontosaurus in 1883, complete with the first-ever restoration of the complete skeleton.

Come play with us, Brontosaurus…forever and ever and ever. Photo courtesy of the AMNH Research Library.

In 1903, Elmer Riggs of the Field Museum of Natural History underwent a survey of sauropod fossils held at various museums and concluded that Brontosaurus excelsus was too similar to Apatosaurus to merit its own genus. The name “Brontosaurus” was dropped, and the species became Apatosaurus excelsus for most of the 20th century. However, a substantial re-evaluation of diplodocoid sauropods by Emanuel Tschopp and colleagues in 2015 reversed Riggs’ decision. So the name Brontosaurus is back, but keep in mind that the species excelsus never actually went anywhere—it was just hidden under the Apatosaurus umbrella. Following Tschopp et al., Apatosaurus and Brontosaurus were distinct animals that lived in the same environment.

So how does the mismatched head fit into all of this? The short answer is that it doesn’t. The fact that some Apatosaurus mounts had incorrect heads for much of the 20th century has nothing to do with which name was being used at any given time, although the two issues have often been conflated in popular books. I suspect the two stories got mixed up because paleontologists were pushing to correct both misconceptions around the same time during the dinosaur renaissance.

Marsh’s second and definitive Brontosaurus reconstruction, first published in 1891.

Let’s go back to Marsh’s 1891 Brontosaurus reconstruction*, pictured above. The Brontosaurus type specimen did not include a head, and many have reported that Marsh used a Camarasaurus skull in this illustration. However, this would not have been possible, because the first complete Camarasaurus skull wasn’t discovered until 1899. What Marsh had instead was a few fragmentary bits of Camarasaurus cranial material, plus a snout and jaw (USNM 5730) now thought to be Brachiosaurus (more on this at SV-POW). Although these pieces were found far from the Brontosaurus quarry, Marsh extrapolated from them to create the best-guess skull that appears in his published reconstruction.

*Note that this is the second of two Brontosaurus reconstructions commissioned by Marsh. The first drawing, published in 1883, has somewhat different skull, but it still does not resemble Camarasaurus.

Although Stephen Gould states in his classic essay “Bully for Brontosaurus” that Marsh mounted the Brontosaurus holotype at the Yale Peabody Museum, Marsh never saw his most famous dinosaur assembled in three dimensions. In fact, Marsh strongly disliked the idea of mounting fossil skeletons, considering it a trivial endeavor of no benefit to science. Instead, it was Adam Hermann of the American Museum of Natural History, supervised by Henry Osborn, who built the original Brontosaurus/Apatosaurus mount (AMNH 460), six years after Marsh’s death in 1899.

Clockwise from top: AMNH sculpted skull (Source), Peabody Museum sculpted skull, real Apatosaurus skull (Source), and real Camarasaurus skull.

To create the mounted skeleton, Hermann combined fossil material from four separate individuals. All of the material had been collected by AMNH teams in Wyoming specifically for a display mount—and to beat Andrew Carnegie at building the first mounted sauropod. Like Marsh, however, they failed to find an associated skull (a Camarasaurus-like tooth was allegedly found near the primary specimen, but it has since been lost). Even today, sauropod skulls are notoriously rare, perhaps because they are quick to fall off and roll away during decomposition. Instead, Hermann was forced to make a stand-in skull in plaster. Osborn explained in an associated publication that this model skull was “largely conjectural and based on that of Morosaurus” (Morosaurus was a competing name for Camarasaurus that is no longer used).

Was it really, though? The sculpted skull is charmingly crude, so the overt differences between the model and a real Camarasaurus skull (top and bottom left in the image above) might be attributed to the simplicity of the model. Note that there isn’t even an open space between the upper and lower jaws! Still, Hermann’s model bears a striking resemblance to Marsh’s illustration in certain details, principally the elongate snout and the very large, ovoid orbit. It’s reasonable to assume that Hermann used Marsh’s speculative drawing as a reference, in addition to any actual Camarasaurus material that was available to him. At the very least, it is incorrect to say that AMNH staff mistakenly gave the mount a Camarasaurus skull, since Osborn openly states that it is a “conjectural” model.

A young Mark Norell leads the removal of the sculpted skull from the classic AMNH Apatosaurus. Source

In 1909, a team led by Earl Douglass of the Carnegie Museum of Natural History finally discovered a real Apatosaurus skull (third image, lower right). They were working at the eastern Utah quarry that is now Dinosaur National Monument, excavating the most complete Apatosaurus skeleton yet found (CM 3018). The skull in question (cataloged as CM 11162) was not connected to the skeleton, but Douglass had little doubt that they belonged together. Back at the Carnegie Museum, director William Holland all but confirmed this when he found that the skull fit neatly with the skeleton’s first cervical vertebra. As he wrote at the time, “this confirms…that Marsh’s Brontosaurus skull is a myth.”

The Carnegie team prepared and mounted the new Apatosaurus, and Holland initially planned to use the associated skull. However, when Osborn heard about this he threatened to ruin Holland’s career if he went through with it. You see, the new skull looked nothing like the round, pseudo-Camarasaurus model skull on the AMNH mount. Instead, it was flat and broad, like a more robust version of Diplodocus. Osborn wasn’t about to let Holland contradict his museum’s star attraction, and Holland backed down, never completing his planned publication on the true nature of Apatosaurus. Meanwhile, the mounted skeleton at the Carnegie Museum remained headless until Holland’s death in 1932. After that, museum staff quietly added a Camarasaurus-like skull. This was an important event, as it would be the first time an actual cast skull of Camarasaurus (as opposed to a freehand sculpture) would be attached to a mounted Apatosaurus skeleton. While I’ve had no luck determining precisely who was involved, Keith Parsons speculated that the decision was made primarily for aesthetic reasons.

Carnegie Museum Brontosaurus circa 1934. Source

Carnegie Museum Apatosaurus alongside the famed Diplodocus, sometime after 1934. Source

Elmer Riggs assembled a third Apatosaurus mount (FMNH P 25112) at the Field Museum in 1908. Riggs had recovered the articulated and nearly complete back end of the sauropod near Fruita, Colorado in 1901, but was unable to secure funding for further collecting trips to complete the mount. Riggs was forced to mount his half Apatosaurus as-is, and the absurd display stood teetering on its back legs for 50 years. Finally, Riggs’ successor Orville Gilpin acquired enough Apatosaurus fossils to complete the mount in 1958. As usual, no head was available, so Gilpin followed the Carnegie Museum’s lead and gave the mount a cast Camarasaurus skull.

The completed mount as it stood in the 1970s, Camarasaurus head and all.

Orville Gilpin finally completed the FMNH Apatosaurus in 1958.

The last classic apatosaurine mount was built at the Yale Peabody Museum of Natural History in 1931, using Marsh’s original Brontosaurus excelsus holotype (YPM 1980) and a lot of plaster padding. The skull this mount originally sported (third image, upper right) is undoubtedly the strangest of the lot. A plaster replica sculpted around a small portion of a real Camarasaurus mandible, this model doesn’t look like any known sauropod. The overall shape is much more elongated than either Camarasaurus or the AMNH model, and may have been inspired by Marsh’s hypothetical illustration. Other details, however, are completely new. The anteorbital fenestrae are thin horizontal slashes, rather than the wide openings in previous reconstructions, while the tiny, forward-leaning nares don’t look like any dinosaur skull—real or imaginary—I’ve ever seen. The sculptor is sadly unknown, but this model almost looks like a committee-assembled combination of the Marsh drawing, the AMNH model, and CM 11162 (a.k.a. the real Apatosaurus skull).

During the mid-20th century, vertebrate paleontology lapsed into a quiet period. Although the aging dinosaur displays at American museums remained popular with the public, these animals came to be perceived as evolutionary dead-ends, of little interest to the majority of scientists. The controversies surrounding old mounts were largely forgotten, even among specialists, and museum visitors saw no reason not to accept these reconstructions (museums are, after all, one of the most trusted sources of information around).

The Peabody Brontosaurus with its original head. Note that the Camarasaurus in the foreground also has a sculpted skull.

This changed with the onset of the dinosaur renaissance in the 1970s and 80s, which brought renewed energy to the discipline in the wake of new evidence that dinosaurs had been energetic and socially sophisticated animals. In the midst of this revolution, John McIntosh of Wesleyan University re-identified the real skull of Apatosaurus. Along with David Berman, McIntosh studied the archived notes of Marsh, Douglass, and Holland and tracked down the various specimens on which reconstructed skulls had been based. They determined that Marsh’s restoration of the Brontosaurus skull, long accepted as dogma, had in fact been almost entirely arbitrary. Following the trail of guesswork, misunderstandings, and scientific inertia, McIntosh and Berman proved that Holland had been right all along. The skull recovered at Dinosaur National Monument along with the Carnegie Apatosaurus was in fact the only legitimate skull ever found from an apatosaurine up to that point. In 1981, McIntosh himself replaced the head of the Peabody Museum Brontosaurus with a cast of the Carnegie skull. AMNH, the Field Museum, and the Carnegie Museum followed suit before the decade was out.

Remounted Apatosaurus at the Carnegie Museum. Photo by the author.

Given the small size of the historic community of dinosaur specialists, it may have been particularly vulnerable to the influences of a few charismatic individuals. To wit, Marsh’s speculative Brontosaurus skull was widely accepted despite a lack of compelling evidence, and Osborn was apparently able to bully Holland out of publishing a find that contradicted the mount at AMNH. What’s more, the legend of the mismatched Brontosaurus skull somehow became distorted by the idea that either Marsh or Osborn had accidentally given their reconstructions the head of Camarasaurus. This is marginally true at best, since both men actually oversaw the creation of composite reconstructions which only passingly resembled Camarasaurus. Nevertheless, the idea that the skull of Camarasaurus was a passable substitute for that of Apatosaurus was apparently well-established by the 1930s, when Carnegie staff hybridized the two sauropods for the first time. Even today, there are numerous conflicting versions of this story, and it is difficult to sort out which details are historically accurate and which are merely assumed.

I’d like to close by pointing out that while the head-swap story is often recounted as a scientific gaffe, it is really an example of science working as it should. Although it took a few decades, the mistakes of the past were overcome by sound evidence. Despite powerful social and political influences, evidence and reason eventually won out, demonstrating the self-corrective power of the scientific process.

References

Berman, D.S. and McIntosh, J.S. 1975. Description of the Palate and Lower Jaw of the Sauropod Dinosaur Diplodocus with Remarks on the Nature of the Skull of Apatosaurus. Journal of Paleontology 49:1:187-199.

Brinkman, P. 2006. Bully for Apatosaurus. Endeavour 30:4:126-130.

Gould, S.J. 1991. Bully for Brontosaurus: Reflections in Natural History. New York, NY: W.W. Norton and Company.

Osborn, H.F. 1905. Skull and Skeleton of the Sauropodous Dinosaurs, Morosaurus and Brontosaurus. Science 22:560:374-376.

Parsons, K.M. 1997. The Wrongheaded Dinosaur. Carnegie Magazine. November/December:38.

Tschopp, E., Mateus, O., and Benson, R.B.J. 2015. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 3:e857. https://doi.org/10.7717/peerj.857

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Filed under AMNH, CMNH, dinosaurs, field work, FMNH, fossil mounts, history of science, museums, reptiles, sauropods, systematics

Tagged as apatosaurus, brontosaurus, dinosaurs, Henry Osborn, museums, O.C. Marsh, paleontology, sauropod

May 9, 2014 · 10:42 am

Mount Making at MMFC14

This past week, I had the fantastic opportunity to be a part of the Mid-Mesozoic Field Conference. I can’t possibly offer enough praise to conference leaders ReBecca Hunt-Foster, Jim Kirkland, and John Foster for pulling off this amazingly informative journey across the Colorado plateau. Unfortunately, since we live in a world where it’s a bad idea to post images of fossil localities, and it’s downright toolish to share details about unpublished research, I won’t be posting a ton about the conference right now.

What I can share, however, are two stops we made that are especially relevant to this blog. The first is the Gaston Design workshop in Fruita, Colorado. Rob Gaston and his team specialize in casting and sculpting fossil replicas, and their mounted skeletons are on display all over North America, but especially at younger museums in the western interior. Gaston showed us how they mold, cast, and sculpt fossil replicas, a process that relies a great deal more on artistic and technical skill than fancy equipment.

This second set of photos is from the College of Eastern Utah Prehistoric Museum in Price, Utah. Ken Carpenter, the museum’s new director, has taken on the task of completely remounting the menagerie of Morrison dinosaurs in the center of the paleontology wing (some photos of the old mounts here). The original Allosaurus, Camptosaurus and Stegosaurus mounts from the late 1980s suffered from an unfortunate case of the tail-drags, and the Camarasaurus had previously been relegated to a death pose. Carpenter’s new mounts, which combine original fossils with new and old reconstructed bones, are much livelier. The stated goal of the project is to encourage visitors to imagine what it would be like to encounter these animals in life. What’s really awesome, though, is that the mounts are being built right in the exhibit, so that visitors can see the progress and the tools and techniques used to build these displays. At present, Allosaurus and Camptosaurus are finished, work on Stegosaurus is underway, and the Camarasaurus skeleton is laid out in pieces.

Sorry to post such a short tease of the awesome stuff we saw at the conference. My head is absolutely packed with information and ideas, so hopefully there will be opportunities to share more soon!

What’s the deal with Astrodon?

In Laurel, Maryland, a trail of banners depicting a herd of the sauropod dinosaur Astrodon johnstoni leads the way to Dinosaur Park, the site of a historically significant fossil deposit. At the Maryland Science Center in Baltimore, a life-sized Astrodon sculpture towers over the “Dinosaur Mysteries” exhibit. And since 1998, Astrodon has been the official state dinosaur of Maryland, joining other state symbols like the black-eyed susan and Baltimore oriole. In short, Astrodon is a sort of mascot for mid-Atlantic paleontology. Named in 1858 for fossils found in a Prince George’s County iron mine, the appeal of Astrodon for Marylanders is obvious: it’s a home-grown dinosaur in a region that is not widely recognized for its fossil resources, and the story of its discovery also calls attention to the state’s industrial heritage.

But what sort of animal was Astrodon, and how much do paleontologists truly know about it? Compared to many other extinct animals found around the world, the fossil record for Astrodon is and always has been fairly poor. The name Astrodon was first bestowed upon nothing more than isolated teeth, and although other fragmentary remains attributed to Astrodon have been uncovered over the past 150 years, reconstructions of the Maryland sauropod are mostly derived from the fossils of relatives found elsewhere. What’s more, the name Astrodon has a convoluted history, having been applied haphazardly to fossils found across the country and even around the world. For these reasons, some paleontologists would prefer that the name Astrodon not be used at all.

Lacking a scientific consensus on what sort of animal the Maryland sauropod was or even what it should be called, I find myself in a difficult position as an educator. How can the messy and contentious taxonomy of Astrodon be condensed into something teachable? Is simplifying or downplaying this controversy doing our audience a disservice, and to what degree?

The taxonomic history of Astrodon

The first scientifically recognized North American dinosaur fossils were found in the Mid-Atlantic region, a scant 17 years after dinosaurs were first recognized as a biological group in 1842. Joseph Leidy’s Hadrosaurus from the New Jersey coast is credited as the first American dinosaur to be described, but Astrodon was a close second. During the mid-19th century, iron mining was big business in central Maryland. Miners extracted large boulders of siderite, or iron ore, from open pit mines throughout Prince George’s County, and these miners were the first in the region to discover dinosaur bones and teeth. The siderite was being mined from clay deposits now known as the Arundel Formation, part of the larger Potomac Group that extends throughout Maryland (the Potomac Group was laid down during the Early Cretaceous period, between 125 and 113 million years ago). Members of the Maryland Academy of Sciences recognized the fossils from the Arundel clay as similar to the English fossil reptiles that Richard Owen had recently unified as Dinosauria. In 1858, academy member Christopher Johnston published a description of a set of teeth from the iron mines in the American Journal of Dental Science, which he named “Astrodon” (Joseph Leidy turned this informal name into a proper binomial, Astrodon johnstoni, in his 1865 review of North American fossil reptiles).

Today, most paleontologists consider it poor judgment to name a new taxon based only on teeth. When scientists describe a newly discovered organism, they designate a type specimen, which is used to define that taxon in perpetuity. But when the type specimen is especially fragmentary, or only consists of a small part of the organism, it poses a problem for future researchers. In the case of Astrodon, no newly discovered fossils other than teeth can be confidently referred to the same species. In 1858, however, paleontological norms were very different. All dinosaur fossils known at the time were exceedingly incomplete: scientists knew that dinosaurs were reptiles and that they were very big and not much else. Any new fossils, even teeth, represented a major addition to our understanding of the life appearance and diversity of these extinct animals. For modern paleontologists, Johnston’s published description of the Astrodon teeth is vague and uninformative, but in his day, these fossils were distinct from anything else yet known.

Astrodon teeth are on the lower left.

In December of 1887, famed paleontologist Othneil Charles Marsh sent his best fossil hunter, John Bell Hatcher, to search the area in Prince George’s County where Astrodon was discovered. Judging from Hatcher’s journal entries, he didn’t have a great time. It rained and snowed almost constantly, and on several days his team didn’t bother to show up for work. Although Hatcher managed to find numerous dinosaur, crocodile and turtle fossils, these finds did not match the quality of the fossils Hatcher had been finding in the western states, and no return trips were made. Nevertheless, Marsh saw fit to name two new dinosaur species from the material Hatcher collected: Pluerocoelus altus and Pluerocoelus nanus. Neither taxon was named for material that would be considered diagnostic if found today: P. altus was based on a tibia and fibula, while P. nanus was based on four nonadjacent vertebrae.

By this time, more complete dinosaur fossils from the American west were beginning to reveal a clearer picture of dinosaur diversity. Based on the shape and size of the fossils collected by Hatcher, Marsh determined that they belonged to sauropods, the group of long-necked herbivores that includes Diplodocus and Apatosaurus. More specifically, Marsh recognized that the Arundel sauropods were similar to “Morosaurus” (now called Camarasaurus) from Colorado. Today, the lineage of stocky, broad-nosed sauropods that includes Camarasaurus and its closest relatives are called macronarians. Unfortunately, by modern standards Marsh’s descriptions of P. altus and P. nanus are rudimentary in nature, and no distinguishing characteristics not common to all macronarian sauropods were offered.

Pleurocoelus elements. Image from NMNH Backyard Dinosaurs.

Pleurocoelus (or Astrodon?) fossils collected by Hatcher. Image from NMNH online exhibit Backyard Dinosaurs.

Contra Marsh, Hatcher suspected that there was only one sauropod in the Arundel Formation. P. altus and P. nanus were probably growth stages of one species, and the Astrodon teeth, now recognized as typical of macronarians, probably came from the same animal, as well. Since the International Code of Zoological Nomenclature decrees that the first published name given to a taxon has priority, Astrodon would take precedence over Pluerocoelus. Later, Charles Gilmore published a review of the Arundel fossils, in which he concurred with Hatcher that P. altus was a junior synonym of Astrodon, but retained P. nanus as a separate species.

Then things started getting really complicated. While paleontologists were still debating how many sauropod species existed in the Arundel clay, Marsh and others had started naming lots of new species of Pluerocoelus. Fossils found in Texas, Oklahoma and even the U.K. were all thrown into the Pluerocoelus bucket, including P. montanus, P. valdensis, P. becklesii and P. suffosus. For much of the 20th century, Pluerocoelus was a classic wastebasket taxon, into which any and all sauropod fossils from early Cretaceous strata were casually thrown. Since the Pluerocoelus type specimens designated by Marsh were insufficient to define the taxon based on morphology, the name became little more than a temporal marker. Adding to the confusion, researchers continued to disagree over whether all these new Pluerocoelus species should be sunk into the earlier genus Astrodon.

In recent years, some progress has been made toward untangling this mess of early Cretaceous sauropods. There is a general consensus that fossils not found in Maryland’s Potomac Group differ substantially from the Arundel sauropods and should never have been referred to Pluerocoelus or Astrodon. New names have been proposed for the midwestern sauropods, including Astrophocaudia and Paluxysaurus. However, removing the non-Maryland fossils from the discussion merely returns us to the original set of problems: how many sauropods are represented in the Arundel clay, what were they like in life, and what should we call them?

Creating a coherent picture of Astrodon

Unfortunately, the answers to these questions depend on who you ask. The most thorough review of Arundel sauropods from the last decade was published by Kenneth Carpenter and Virginia Tidwell in 2005. Carpenter and Tidwell reaffirmed Hatcher’s conclusion that Pluerocoelus is synonymous with Astrodon, and that as the earliest published name, Astrodon has priority. This decision is apparently based only on the fact that the fossils came from the same stratum, however, since the Astrodon holotype cannot be compared to anything besides other teeth. For this reason, Michael D’Emic proposed in 2012 that the names Astrodon and Pluerocoelus are nomen dubia and should both be dropped entirely. Ultimately, neither solution is practical for identifying the sauropod fossils that continue to be collected from the Arundel Formation. Either we blindly refer any and all sauropod fossils to Astrodon, even though we lack a usable holotype, or we have no label available at all. One solution would be to establish a new type specimen (called a neotype) for Astrodon, but this has yet to be done.

Both camarasaur and brachiosaur shaped Astrodon reconstructions are equally reasonable.

Both camarasaur and brachiosaur-shaped Astrodon reconstructions are reasonable. Artwork by Dmitry Bogdanov, via Wikipedia.

While many more sauropod fossils have been found in the Arundel clay since Hatcher’s 1887 expedition, we do not have enough material to fully elucidate what these animals looked like. Size estimates have varied enormously, from as little as 30 feet to as much as 80 feet in length. The assortment of fossil bones and teeth that have been found tell us we have a macronarian sauropod, and we can reconstruct its general shape based on more completely known relatives. However, macronarians were a fairly diverse bunch, ranging from the comparatively stocky camarasaurs to high-shouldered, elongate brachiosaurs. Carpenter and Tidwell describe the Arundel sauropod fossils, particularly the limb bones, as being fairly slender, but still more robust than those of Brachiosaurus. They do recognize, however, that nearly all known Arundel sauropod fossils come from juveniles, which may vary proportionally from adults. Because the precise affinities of Astrodon are unclear, artistic reconstructions vary substantially. The National Museum of Natural History’s Backyard Dinosaurs exhibit and website shows a camarasaur-shaped sauropod, while the life-sized sculpture at the Maryland Science Center is based on the brachiosaur Giraffatitan. At Dinosaur Park in Laurel, meanwhile, both versions are on display. More fossils, ideally cervical vertebrae or more complete adult material, are needed to clarify what the Arundel sauropod looked really like.

Teaching Astrodon

When I show people the teeth and partial bones attributed to Astrodon during public programs, I am almost always asked, “if that’s all you’ve found, how do you know what the whole animal looked like?” As demonstrated by this post, it takes 1,700 words and counting to give a proper answer, which is too much for all but the most dedicated audiences. Nevertheless, to do anything less is to skip crucial caveats and information. Scientists are choosy about the words they use, filling explanations with “probablys” and “almost certainlys”, but they do so with good reason: when one’s job is to create and communicate knowledge, there is no room for ambiguity about what is and is not known. It is therefore just a bit dishonest to say that a large sauropod called Astrodon that was related to Brachiosaurus lived in Maryland, and yet I do so every week. How can I possibly sleep at night?

I’ll admit it can be difficult, but I get by because using one proviso-free name for the Maryland sauropod seems to be informative and helpful to my audience. I only have people’s attention for so long, and I’d rather not spend that time on tangents about how Astrodon should really be called Pluerocoelus or why my use of either name is imprecise and problematic. I want visitors to walk away understanding how paleontologists assemble clues from sedimentary structures and anatomical comparisons to reconstruct ancient environments and their inhabitants. I’d like for visitors to practice making observations and drawing conclusions, and understand how paleontology is a meticulous science that can be relevant to their lives. “Paleontologists are weirdly obsessed with changing names” is not one of the most important things to know about paleontology.

Taxonomy, the science of naming and identifying living things, is unquestionably valuable. Biologists would be lost without the ability to differentiate among taxa. From my perspective, however, the public face of paleontology tends to overemphasize taxonomic debates in lieu of more informative discussions. There will always be somebody willing to argue whether Tarbosaurus bataar should be sunk into Tyrannosaurus, or to give incorrect explanations for why we lost “Brontosaurus.” In the end, though, these debates have more to do with people’s preferences than the actual biology of these animals. Astrodon may not be a diagnostic taxon in the strictest sense, but we need to call our fossils something, and taxonomic labels exist to be informative and useful. If asked, I’m always happy to provide the full story. But for the time being, Astrodon seems to be working just fine.

References

Carpenter, K. and Tidwell, V. 2005. Reassessment of the Early Cretaceous sauropod Astrodon johnstoni Leidy 1865 (Titanosauriformes). In Carpenter and Tidwell (eds.), Thunder-Lizards: The Sauropodomorph Dinosaurs. Bloomington, IA: Indiana University Press.

D’Emic M.D. 2012. Revision of the sauropod dinosaurs of the Lower Cretaceous Trinity Group, southern USA, with the description of a new genus. Journal of Systematic Paleontology, iFirst 2012, 1-20.

Gilmore, C.W. 1921. The fauna of the Arundel Formation of Maryland. Proceedings of the United States National Museum. 59: 581-594.

Kranz, P.M. Dinosaurs in Maryland. 1989. Published by Maryland Geological Survey, Department of Natural Resources, Educational Series No. 6.

Marsh, O.C. 1888. Notice of a New Genus of Sauropoda and Other New Dinosaurs from the Potomac Formation.

Please note that the usual disclaimer applies: views or opinions expressed here are mine, and do not reflect any institution with which I am affiliated.

Extinct Monsters: Brachyceratops

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

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.

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.

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.

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.

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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Filed under dinosaurs, exhibits, Extinct Monsters, field work, fossil mounts, history of science, marginocephalians, museums, NMNH, reptiles

Tagged as dinosaurs, Extinct Monsters, fossil mounts, museums, NMNH, Smithsonian

November 15, 2013 · 7:31 pm

First Full-Sized Dinosaurs: From Crystal Palace to Hadrosaurus

Last time, we covered how Albert Koch turned a tidy profit with his less-than-accurate fossil mounts, leading credible paleontologists to avoid involvement with full-sized reconstructions of extinct animals for much of the 19^th century. With the exceptions of Juan Bautista Bru’s ground sloth and Charles Peale’s mastodon, all the fossil mounts that had been created thus far were horrendously inaccurate chimeras assembled by often disreputable showmen. Serious scientists were already struggling to disassociate themselves from these sensationalized displays of imaginary monsters, so naturally they avoided degrading their work further by participating in such frivolous spectacle.

The prevailing negative attitude toward fossil mounts among academics would begin to shift in 1868, when paleontologist Joseph Leidy and artist Benjamin Waterhouse Hawkins collaborated on a mount of Hadrosaurus, the first dinosaur to be scientifically described in America and the first dinosaur to be mounted in the world. While prehistoric animals were well known by the mid-19^th century, the Hadrosaurus was so bizarre, so utterly unlike anything alive today, that it truly opened people’s eyes to the unexplored depths of the Earth’s primordial history. I have written about the Hadrosaurus mount before, but its creation was such a landmark event in the history of paleontology and particularly the public understanding of prehistory that it deserves to be contextualized more thoroughly.

Discovering Dinosaurs in Britain

In the early 1800s, American fossil hunters were busy poring over the bones mammoths, mastodons and other mammals. Across the Atlantic, however, it was all about reptiles. Scholars were pulling together the first cohesive history of life on earth, and Georges Cuvier was among the first to recognize distinct periods in which different sorts of creatures were dominant. There had been an Age of Mammals in the relatively recent past during which extinct animals were not so different from modern megafauna, but it was preceded by an Age of Reptiles, populated by giant-sized relatives of modern lizards and crocodilians. The marine ichthyosaurs and plesiosaurs unearthed by Mary Anning on the English coast were the first denizens of this era to be thoroughly studied, but they were soon followed by discoveries of terrestrial creatures. In 1824, geologist William Buckland received a partial jaw and a handful of postcranial bones found in the Oxfordshire shale. Recognizing the remains as those of a reptile, Buckland named the creature Megalosaurus, making it the first scientifically described non-avian dinosaur (honoring the unspoken agreement to ignore “Scrotum humanum”).

The partial jaw of Megalosaurus, the first named dinosaur.

Of course, the word “dinosaur” did not yet exist. As covered by virtually every text ever written on paleontological history, it was anatomist Richard Owen who formally defined Dinosauria in 1842 as a distinct biological group. Owen defined dinosaurs based on anatomical characteristics shared by Megalosaurus and two other recently discovered prehistoric reptiles, Iguanodon and Hylaeosaurus (fatefully, and somewhat arbitrarily, he excluded pterosaurs and doomed paleontologists and educators to forever reminding people that pterodactyls are not dinosaurs). In addition to being an extremely prolific author (he wrote more than 600 papers in his lifetime), Owen was a talented publicist and quite probably knew what he was unleashing. The widely publicized formal definition of dinosaurs, accompanied by displays of unarticulated fossils at the Glasgow Museum, was akin to announcing that dragons were real. By giving dinosaurs their name, Owen created an icon for the prehistoric past that the public could not ignore.

“Dinosaur” soon became the word of the day in Victorian England. Looking to capitalize on this enthusiasm for paleontology, the Crystal Palace Company approached Owen in 1852 to oversee the creation of an unprecedented new exhibit. The company was building a park in the London suburb of Sydenham, meant to be a permanent home for the magnificent Crystal Palace, which had been built the previous year for the Great International Exhibition of the Works and Industry of All Nations. Concerned that the palace would not draw visitors to the park on its own, the Crystal Palace Company commissioned Owen and scientific illustrator Benjamin Waterhouse Hawkins to create a set of life-sized sculptures of dinosaurs and other prehistoric creatures, the first of their kind in the world. The sculptures were a tremendous undertaking: the Iguanodon, for instance, was supported by four 9-foot iron columns, and its body was built up with brick, tile and cement. Hawkins then sculpted its outer skin from more than 30 tons of clay. All told, more than a dozen animals were built, including Megalosaurus, Iguanodon, Hylaeosaurus and an assortment of marine reptiles and mammals.

The Crystal Palace dinosaurs under construction in Hawkin’s studio.

Queen Victoria herself presided over the opening ceremony of Crystal Palace Park in 1854, which was attended by 40,000 people. This was an important milestone because up until that point, only the broadest revelations in geology and paleontology made it out of the academic sphere. But as Hawkins himself put it, the Crystal Palace dinosaurs “might be properly described as one vast and combined experiment of visual education” (Hawkins 1853, 219). The general public could see firsthand the discoveries and conclusions of the most brilliant scientists of their age, in a format that could not only be readily understood and appreciated, but experienced. Full-sized reconstructions of prehistoric animals, including fossil mounts, continue to be built today for precisely this reason.

Recently restored Iguanodon sculptures. Wikimedia Commons.

Recently restored Iguanodon sculptures at Crystal Palace Park. Source

While the Crystal Palace dinosaurs are important historic artifacts and beautiful works of art in their own right, they have not aged well as accurate reconstructions. Owen only had the scrappiest of dinosaur fossils to work with, enough to conclude that they were reptiles and that they were big but not much else. As a result, the Megalosaurus and Iguanodon sculptures look like rotund lizards, as though a monitor lizard or iguana gained the mass and proportions of an elephant. By modern standards, these beasts look pretty ridiculous as representations of dinosaurs, but they were quite reasonable given what was known at the time, at least for a few years.

Dinosaurs of the Jersey Shore

And so at last Hadrosaurus enters the story. Just four years after the unveiling of the Crystal Palace sculptures, the first American dinosaur was found on a farm near Haddonfield, New Jersey (dinosaur footprints and teeth had been found earlier, but their affinity with the European reptiles was not recognized until later). William Foulke, a lawyer and geology enthusiast affiliated with the Philadelphia-based Academy of Natural Sciences, was at his winter home in Haddonfield when he paid a visit to his neighbor, John Hopkins. Hopkins told Foulke that he occasionally found large fossils on his land, which he generally gave away to interested friends and family members. With Hopkins’ permission, Foulke searched the site where the fossils had been found with the assistance of paleontology and anatomy specialist Joseph Leidy. Also a member of the Academy of Natural Sciences, Leidy is considered the founder of American paleontology and during the mid-1800s, he was the preeminent expert on the subject. At the Haddonfield site, Foulke and Leidy uncovered approximately a third of a dinosaur skeleton, including two nearly complete limbs, 28 vertebrae, a partial pelvis, scattered teeth and two jaw fragments.

All known Hadrosaurus fossils, presently on display at the Academy of Natural Sciences.

Now in possession of the most complete dinosaur skeleton yet found, Leidy began studying the fossils of what he would name Hadrosaurus foulkii (Foulke’s bulky lizard) in Philadelphia. The teeth in particular told Leidy that Hadrosaurus was similar to the European Iguanodon. Like Iguanodon, Hadrosaurus was plainly an herbivore, and for reasons left unspecified Leidy surmised that it was amphibious, spending most of its time in freshwater marshes. Leidy noted that Hadrosaurus was a leaner and more gracile animal than Owen’s Crystal Palace reconstructions, but he was particularly interested in “the enormous disproportion between the fore and hind parts of the skeleton” (Leidy 1865). Given the large hindlimb and small forelimb, Leidy reasoned that Hadrosaurus was a habitual biped, and likened its posture to a kangaroo, with an upward-angled trunk and dragging tail. As such, we can credit Leidy for first envisioning the classic Godzilla pose for dinosaurs, which has been known to be inaccurate for decades but remains deeply ingrained in the public psyche.

Although the new information gleaned from Hadrosaurus made it clear that the Crystal Palace sculptures were hopelessly inaccurate, Leidy had been impressed by the Sydenham display and wanted to create a similar public attraction in the United States. Leidy invited Hawkins to prepare a new set of prehistoric animal sculptures for an exhibit in New York’s Central Park. Hawkins set up an on-site studio and began constructing a life-sized Hadrosaurus, in addition to a mastodon, a ground sloth and Laelaps, another New Jersey dinosaur. Unfortunately, Hawkins’ shop was destroyed one night by vandals, apparently working for corrupt politicians. What remained of the sculptures was buried in Central Park and the exhibit was cancelled.

Edit 4/20/2017: Leidy was not actually involved in planning the ill-fated Central Park display. Thanks to Raymond Rye for the tip!

The “Bulky Lizard” Mount

Instead of abandoning the project entirely, Hawkins and Leidy redirected the resources they had already prepared for the Central Park exhibit into a display at the Academy of Natural Sciences museum in Philadelphia. Leidy decided he wanted a mounted skeleton of Hadrosaurus, rather than a fully fleshed model as was originally planned. Such a display had not appeared in a credible museum since Charles Peale created his mastodon mount, but if anybody could get a fossil mount to be taken seriously, it was Leidy.

With only a partial Hadrosaurus skeleton to work with, Hawkins had to sculpt many of the bones from scratch, in the process inventing many of the mounting techniques that are still in use nearly a century and a half later. For instance, Hawkins created mirrored duplicates of the left limb bones for use on the animal’s right side, and reconstructed best-guess stand-ins for the skull, scapulae and much of the spinal column using modern animals as reference. Based on photographs like the one below, it appears that portions of the vertebral column were cast as large blocks, rather than individual vertebrae. The mount was supported by a shaped metal rod running through the vertebrae, as well as a single vertical pole extending from the floor to the base of the neck. In fact, very little of the armature appears to have been externally visible, suggesting that making the skeleton as aesthetically clean as possible was a priority.

Hadrosaurus under construction in Hawkins’ studio. Note the flightless bird mounts used for reference. From Carpenter et al. 1994.

The Hadrosaurus mount had a few eccentricities that are worth noting. First, the mount has seven cervical vertebrae, which is characteristic of mammals, not reptiles. Likewise, the scapulae and pelvis are also quite mammal-like. Hawkins was apparently using a kangaroo skeleton as reference in his studio, and it is plausible that this was the source of these mistakes. In addition, Hawkins had virtually no cranial material to work with (despite several repeat visits to the Haddonfield site by Academy members searching for the skull), so he had to make something up. He ended up basing the his sculpted skull on an iguana, one of the few exclusively herbivorous reptiles living today. Although fossils of Hadrosaurus relatives would later show that this was completely off the mark, it was very reasonable given what was known at the time.

The Hadrosaurus mount was unveiled at the Academy of Natural Sciences musuem in 1868, and the response was overwhelming. The typical annual attendance of 30,000 patrons more than doubled that year to 66,000, and the year after that saw more than 100,000 visitors. Traffic levels were so high that the Academy had to decrease the number of days it was open and enforce limits on daily attendance in order to prevent damage to the rest of the collection. Soon, the Academy was forced to relocate to a new, larger building in downtown Philadelphia, which it still occupies today.

The audience for the Hadrosaurus mount was expanded greatly in the 1870s by three plaster copies of the skeleton, which were sent to Princeton University in New Jersey, the Smithsonian Institution in Washington, DC and the Royal Scottish Museum in Edinburgh (the first dinosaur mount displayed in Europe). The Smithsonian copy had a particularly mobile existence: it was first displayed in the castle on the south side of the National Mall, moved to the dedicated paleontology display in the Arts and Industries Building around 1890, and finally traded to the Field Museum in Chicago later in the decade. In Chicago, the Hadrosaurus was displayed in a spacious gallery alongside mounts of Megaloceros and Uintatherium, and it is in this context that the best surviving photographs of the Hadrosaurus mount were taken. Sadly, by the early 1900s all three casts had been destroyed or discarded by their host institutions, since they had either deteriorated badly or were deemed too inaccurate for continued display. The original Philadelphia mount was also dismantled, although the Hadrosaurus fossils are still at the Academy.

Hadrosaurus cast on display at the Field Museum. Field Museum Photo Archives.

Why was the Hadrosaurus mount such a big deal? For one thing, it was different from previous fossil mounts in that it was the product of the best scientific research of the day. This was not the work of a traveling showman but a display created by the preeminent scientific society of the era, with all the mystique and prestige that came with it. Most importantly, however, the Hadrosaurus mount presented the first ever opportunity to stand in the presence of a dinosaur. By the mid-19th century, western civilization had had ample opportunity to come to terms with the fact that organisms could become extinct, but for the most part the fossils on display were similar to familiar animals like horses, elephants and deer. The Hadrosaurus, however, was virtually incomparable to anything alive today. It was a monster from a primordial world, incontrovertible evidence that the Earth had once been a very different place. By comparison, the Crystal Palace sculptures were essentially oversized lizards, and therefore fairly relateable. The Hadrosaurus was the real turning point, the moment the public got their first glimpse into the depths of prehistory. For 15 years, the Hadrosaurus was the only real dinosaur on display anywhere in the world, so it is no wonder that people flocked to see it.

Of course, the Hadrosaurus was only the beginning of the torrent of dinosaur fossils that would be unearthed in the late 19th century. It would prove to be but a hint at the amazing diversity and scale of the dinosaurs that would be revealed in the American west, as well as the scores of fossil mounts that would soon spring up in museums.

References

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

Leidy, J. (1865). “Cretaceous Reptiles of the United States.” Smithsonian Contributions to Knowledge. 14: 1-102.

Waterhouse Hawkins, B. (1853). “On Visual Education as Applied to Geology.” Journal of the Society of Arts. 2: 444-449.

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Filed under anatomy, dinosaurs, field work, fossil mounts, history of science, museums, ornithopods, paleoart, reptiles

Tagged as Academy of Natural Sciences, Benjamin Waterhouse Hawkins, Crystal Palace, dinosaurs, fossil mounts, Hadrosaurus, Joseph Leidy

October 7, 2013 · 9:15 am

The Artist in His Museum: Peale’s Mastodon

In 1801, naturalist and painter Charles Wilson Peale assembled in Philadelphia the skeleton of a mastodon (Mammut americanum).While Peale’s mastodon was not the first fully assembled fossil animal put on display, it was assuredly the first display of this type to capture widespread public attention, particularly in the United States. What’s more, the mastodon became an important symbol for the untold natural wonders of the American continent, which was still largely unexplored (by European colonists) at the beginning of the 19th century. Finally, Peale’s mastodon made clear to the public one of the most important principles of modern biology: the idea that organisms can become extinct.

The Peale Museum mastodon, as illustrated by Charles Peale's son, Rembrandt.

An extinct giant

The story of the mastodon mount actually began a full century before the 1806 debut. In 1705, a farmer in Claverack, New York found an enormous tooth that had eroded out of a hillside. The farmer traded the tooth to a local politician, and it eventually made it its way into the hands of New York’s colonial governor, Edward Hyde, 3rd Earl of Clarendon. Hyde in turn sent the tooth to London, describing it as a remnant of an antediluvian giant. As word of the remains of a giant spread, other Americans soon began reporting similar finds. Throughout the colonies, giant bones, teeth, and tusks began to be uncovered. While early reports called these fossils the remains of “incognitum,” or “the unknown,” naturalists caught on reasonably quickly that these were not the bones of giant men but of elephant-like creatures.

At this point a brief digression on etymology and taxonomy is required. For most of the 19th century, the American fossil elephants were invariably called “mahmot” or “mammoth.” This was an Anglicization of the Old Vogul term maimanto (meaning earth-horn), which referred to giant tusks occasionally found in Siberia. It is unclear, however, who first made the correct connection between the frozen mammoths of Siberia and the American fossil skeletons. Credit for adopting “mammoth” as a synonym for “big” goes to Thomas Jefferson, who was fascinated by paleontology and the mammoth fossils in particular.

It was not until 1817 that French anatomist Georges Cuvier recognized that there were at least two types of extinct American proboscideans: the taller mammoths and stockier mastodons. Unequivocally demonstrating the staggering repression of the Victorian era, Cuvier coined the name “mastodon,” meaning nipple tooth, because apparently he thought the animal’s most distinguishing feature was that its teeth looked like breasts.

The American elephantine fossils raised difficult questions for naturalists. The fossils clearly belonged to animals that had never been seen alive, which meant that the entire species must have died out. This concept of extinction was new to science, and it challenged the biblically-inspired presumption that all species had originated in a single creation event. Cuvier was a leader in the 19th century scientific movement known as catastrophism–the idea that extinctions were the result of periodic disasters, such as floods. While Cuvier himself rejected the idea that populations of organisms could avoid extinction by adapting and changing, his work on extinction would prove important when Charles Darwin worked out the process of evolution several decades later.

Unearthing the mastodon

In 1789, Nicholas Collin of the American Philosophical Society proposed a search for a complete mammoth skeleton, in order to resolve the animal’s identity and the question of its extinction once and for all. Collin’s call was answered by Charles Wilson Peale, founder of America’s first modern museum. Peale is best known today as a portrait artist during the American Revolution, but he was also the founder of the Peale Museum in Philadelphia. Although semi-formal collections of interesting natural specimens had existed before, Peale uniquely fashioned his institution as a space for public education, rather than a private vanity project. On the second floor of Philadelphia’s Independence Hall, Peale arranged displays of mammals, birds, and plants in a scala naturae, which was the contemporary understanding of natural order. Peale intended the museum to be a public resource that would improve visitors’ moral character through lessons in science, as was made clear by the slogan printed on every ticket, “the birds and beasts will teach thee.”

In 1799, a farmer named John Masten reported that he had found bones of “an animal of uncommon magnitude” on his land outside Newburgh, New York. Masten gathered a large party of friends and neighbors to help excavate the find. This proved to be a little too much fun: the crowd eventually descended into alcohol-fueled chaos, and many of the fossils were destroyed. Nevertheless, Peale decided to pay Masten a visit, with the hope of securing mammoth fossils for his museum. Peale ended up paying Masten $200 for the surviving fossils, plus another $100 for the right to search his land for more remains. Peale returned to Masten’s farm with a better-organized crew and $500 in additional funding from the American Philosophical Society. The ensuing excavation is the subject of Peale’s 1806 painting, The Exhumation of the Mastodon, shown below.

Although highly dramatized, The Exhumation of the Mastodon provides the best available record of the event. Since the pit where Masten first found the bones had filled with water, Peale oversaw the construction of a huge wooden wheel, which drove a conveyor belt hauling buckets of water out of the work site. Peale himself can be seen on the right, presiding over his small army of excavators. The well-publicized project eventually uncovered most of a mastodon. Exploring a few nearby farms, Peale’s workers eventually accumulated enough material to build a complete skeleton, most notably a mandible found on another farm down the road. In what was either showmanship or genuine confusion regarding the diets of elephants, Peale said of the find, “Gracious God, what a jaw! How many animals must have been crushed beneath it!” (quoted in Simpson 1942, 159).

The mastodon on exhibit

Once the mastodon skeleton had been transported to Philadelphia, the process of building the mount fell upon Peale’s son Rembrandt and Moses Williams, a free man of color who worked for the Peales. It took three months to articulate the skeleton, although sadly the details of how it was mounted on its armature are lost to history. Initiating a practice that would become necessity for most fossil mounts in years to come, Rembrant filled in missing parts of the mastodon skeleton (the top of the cranium and the tail) with sculpted elements. In addition, wooden discs were placed between vertebrae, slightly exaggerating the mount’s total length.

The completed mastodon mount was unveiled in 1802, in the main hall of the American Philosophical Society. Shortly thereafter, it was moved to the Peale Museum at Independence Hall. For 50 cents (plus regular admission), the visiting public could marvel at the creature Peale touted as “the first of American animals” and “the largest of terrestrial beings.” The mastodon (still being called a mammoth at that time) was a sensation, stirring up fascination with natural science, the prehistoric past, and no small amount of ours-is-bigger-than-yours patriotism in the young United States. In 1822, Peale would commemorate the unveiling of the mastodon with his self portrait, The Artist in His Museum. Ever the showman, Peale ensured that the skeleton in his painting is only barely visible below the rising curtain.

After Peale’s death in 1827 his museum floundered, and was eventually reduced from a meritorious educational institution into a circus of cheap spectacle. It shut down for good in 1848, and the mastodon (by then one of many similar mounts) was put up for auction. There are several conflicting accounts of what became of the mount, including the suggestion that it was destroyed in a fire, but in fact Peale’s mastodon has survived to the present day. Johann Jakob Kaup purchased the skeleton for the Landesmuseum in Durmstadt, Germany, and it has remained on display there ever since.

Peale’s mastodon left an unmistakable legacy for both paleontology and public education. Today, the public conception of prehistory is inseparably connected to the image of towering mounted skeletons in museum halls. But fossils do not come out of the ground bolted to steel armatures, so it is largely thanks to Peale that mounts have become the most enduring means of sharing paleontology with the public.

References

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

Connriff, R. (2010). Mammoths and Mastodons: All American Monsters. Smithsonian Magazine. http://www.smithsonianmag.com/science-nature/Mammoths-and-Mastodons-All-American-Monsters.html

Semonin, P. (2000). American Monster: How the Nation’s First Prehistoric Creature Became a Symbol of National Identity. New York, NY: New York University Press.

Simpson, G.G. (1942). The Beginnings of Vertebrate Paleontology in North Ameirca. Proceedings of the American Philosophical Society 86:130-188.

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Filed under field work, fossil mounts, history of science, mammals, museums

Tagged as fossils, history of science, mammoth, mastodon, museums, natural history museums, paleontology

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