Category Archives: field work

A Tour of Dinosaur Park

I generally use this blog to write about other people’s work, but today I’m going to turn the tables and share a project I’ve been involved with for the past couple years. As of this month, the new interpretive area at Laurel, Maryland’s Dinosaur Park is (just about) complete. I’m proud of my own contributions, and ecstatic with all the work my immeasurably talented and dedicated colleagues have done to bring this project to fruition.

Introductory sign at Dinosaur Park.

Dinosaur Park is a 41-acre site operated by the Maryland-National Capital Park and Planning Commission that preserves the most productive dinosaur fossil quarry in the eastern United States. Historically known as the Muirkirk quarry, this location has been a known source of dinosaur material since 1858. Fossils were first discovered by ironworkers collecting siderite for processing at the nearby Muirkirk ironworks. Later, O.C. Marsh, John Bell Hatcher, Charles Gilmore, Richard Lull and other prominent paleontologists would collect or study fossils from this deposit. The site was largely forgotten for most of the 20th century, but in the 1980s Peter Kranz, Tom Lipka, and others relocated it and began unearthing new material. Highlights included a massive sauropod femur, basal ceratopsian teeth, and the only Mesozoic mammal fossils ever found east of the Mississippi River.

The Muirkirk quarry produced some of the first dinosaur fossils to be scientifically studied in North America, and as such conceptions of its position in geologic time have understandably changed over the years. Marsh assumed the site was Jurassic in age because of the presence of sauropods, but Gilmore later revised it to Cretaceous. Based on pollen data, we can now place the site (and the Patuxant Formation as a whole) at the Aptian-Albian boundary in the Lower Cretaceous. Contrary to older proposals, the Muirkirk dinosaur fauna has more in common with the middle strata of the Cedar Mountain Formation in Utah than the Wealden Group in England.

Excavating a sauropod femur at the future site of Dinosaur Park in 1991. Photo courtesy of Pete Kroehler.

Dinosaur Park fossils aren’t much to look at, but they are remarkable for their diversity. This is a record of a complete ecosystem.

Thanks to some determined lobbying, the M-NCPPC (a bi-county organization that administers parks and urban planning) acquired the Muirkirk site and formally dedicated Dinosaur Park in October 2008. From its inception, Dinosaur Park was conceived as a citizen science project. During school programs and regularly scheduled open houses, visitors are invited to take part in ongoing prospecting for fossils. These programs emphasize stewardship of natural heritage, rather than treasure hunting, and to date visitors have discovered thousands of specimens. All of these fossils are accessioned into the county’s collection for research and education, and important specimens are turned over to the National Museum of Natural  History for final curation (search the NMNH Paleobiology collections database for “Arundel” to view this material).

Citizen scientists prospecting for fossils at Dinosaur Park.

Back in 2008, there wasn’t much to Dinosaur Park beyond the fossil site, a protective fence, and a small gravel parking lot. There were always plans to further develop the site, however, and thanks to the Park’s ongoing popularity we were able to kick off the phase II construction in 2016. The project involved developing the entrance area with exhibits and visitor amenities. There wasn’t a lot of space to work with, and the new facilities would have to do double duty: they needed to be useful both during guided programs and for drop-in visitors during the week (when the fossil site is closed). We ended up with an integrated, multipurpose space incorporating a series of exhibit signs, a garden of “living fossil” plants, a presentation area, a climbable dinosaur skeleton, two picnic benches, and a restroom and drinking fountain.

A number of additions were – to the probable annoyance of my colleagues –  the result of me piping up with a last-minute “wouldn’t it be cool if…” suggestion. That’s how we ended up with a life-sized image of the Astrodon femur discovered by the Norden  family in 1991, a trail of sauropod footprints, and a series of displays about baby sauropods (perhaps there’s a theme there?).

The garden, play area, and other new facilities at Dinosaur Park.

One of several new interpretive signs.

The content of the exhibit signs was directly informed by formal and informal visitor surveys. We took note of visitors’ most frequent questions, as well as which parts of our old displays were being ignored or misunderstood. For example, lots of visitors wanted to know about the biggest or most important fossils found at the Park. These weren’t illustrated on our old signs, but they’re integral parts of the new ones. Meanwhile, very few visitors were engaging with content about local geology, so those sections ended up being cut.

A section of Shoe’s masterful Cretaceous Maryland mural. Artwork by Clarence Schumaker, courtesy of the M-NCPPC.

For me, and hopefully many visitors, the highlight of the new displays is the spectacular mural created by Clarence “Shoe” Schumaker. Shoe has produced artwork for numerous parks and museums, including several National Park Service facilities, but to my knowledge he had never painted dinosaurs before. Nevertheless, he approached the project with unquenchable enthusiasm, determined to get every detail correct. Working with Shoe was a fantastic experience – I would send him my hasty sketches and random ideas and he would somehow turn them into spectacular imagery. Our goal was to produce an image that would be at home in any nature center. This is an overview of an ecosystem, and the presence of dinosaurs is only by happenstance. The final piece is mesmerizing, and I think its hyper-detailed placidity gives it a certain Zallinger-like quality.

The finished mural was so cool that I couldn’t help but ask for more. One under-reported virtue of the Dinosaur Park collection is that we have sauropod remains from a variety of ages and sizes – from 70-foot adults to tiny hatchlings. I suggested a single image of a baby sauropod to help illustrate these animals’ remarkable growth potential. Shoe turned around and produced two full paintings and a life-sized model. The man is seriously unstoppable.

Shoe’s 2D and 3D baby Astrodon art. Artwork by Clarence Schumaker, courtesy of the M-NCPPC.

It’s been a wonderful experience seeing the Dinosaur Park interpretive area come together, and the few places where compromises were made are vastly overshadowed by the many prominent successes. Dinosaur Park is an important resource, both for growing our knowledge of prehistory and for introducing the local community to the process of scientific discovery. I can’t wait to see it continue to grow!

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Filed under citizen science, Dinosaur Park, dinosaurs, education, exhibits, field work

Dispatch from SEAVP2016

Wow, it’s been awhile. The real world has been keeping me busy, but I’ve been researching a couple new museum  history stories that I will write up with all haste. In the meantime, I’d like to share some brief thoughts on the Southeast Association of Vertebrate Paleontology conference at the Virginia Museum of Natural History, which I attended earlier this week. SEAVP has a reputation for being fairly laid back, even as gatherings of paleontologists go. No frantic networking or jostling to introduce oneself to celebrity researchers, just a bunch of enthusiastic people excited to share their work.

Acrocanthosaurus is photobombed by some legless mammal.

Acrocanthosaurus is photobombed by some legless mammal.

With 50-some attendees, nearly everyone was either speaking or presenting a poster. Miranda Armour-Chelu took on the challenge of reconstructing the taphonomic circumstances surrounding historically collected dugong fossils. Marcelo Kramer shared his adventures prospecting for Quaternary fossils in unexplored caves in northern Brazil. Julie Rej explained the difficulty of identifying Australian agamid fossils when most modern comparative collections in museums consist of pickled lizards, rather than bones. My own talk was a show-and-tell session of some of the cool new fossils discovered by visitors to Maryland’s Dinosaur Park. If I had to pick a standout session, it would be C.T. Griffin’s fascinating research comparing the growth trajectories of early dinosaurs to modern birds and crocodillians. Not as straightforward as one might expect.

Splitting shale at the Solite Fossil Site.

Splitting shale at the Solite Fossil Site.

tanywhatsit

Max’s tanywhatsit fossil.

The following day, we visited the famed Solite Fossil Site, one of the most fossiliferous terrestrial Triassic localities in the world. These shales are best known for preserving an abundance of unique insects, but vertebrates and diagnostic plant fossils are also known. In particular, the site has produced hundreds of the tiny long-necked reptile Tanytrachelos. It only took 20 minutes for my colleague Max Bovis to find a “tany”, and an hour later he reportedly found a fossil fish. Both will be entered into the VMNH collection. We also visited Virginia Tech, where Michelle Stocker and Sterling Nesbit provided a tour of the paleobiology department facilities. We saw unique fossils from Ghost Ranch, New Mexico and the extant comparative specimen lab, but I was most envious of their 3-D printing set-up!

An immersive

An immersive habitat diorama featuring the Ice Age beaver Castoroides.

What of the exhibits at VMNH? They’re fantastic. Despite the museum’s small size, the production quality on all the displays is really top notch. The Uncovering Virginia hall highlights several fossil sites around the state, including the Ice Age mammals from Saltville, the coal seams of Grundy, and the aforementioned Solite quarry. In addition to original specimens and reconstructions of the excavations, there are a number of inspired hands-on activities. Visitors can put a whale jaw back together and articulate a femur with a pelvis, mirroring challenges actually faced by fossil preparators (nary a sandbox dig in sight!). I also liked a multimedia display where pressing a button (labeled “press here to go back in time”) pulls back an image of the Grundy coal mine and reveals a moving diorama of a Carboniferous coal swamp.

The central Hall of Ancient Life features local whale and Ice Age fossils, as well as some visiting dignitaries like a cast of Big Al the Allosaurus. Don’t forget to check out the second floor balcony, which contains Morrison Formation dinosaur bones and a secret Tenontosaurus mount.

aww

Group photo courtesy of Alex Hastings, VMNH.

All in all, an excellent conference – hats off to Alex Hatings, Christina Byrd, and everyone else involved in arranging it. I’m looking forward to next year’s meeting, which will be hosted by the Gray Fossil Site Museum in Tennessee!

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Filed under citizen science, Dinosaur Park, dinosaurs, education, exhibits, field work, mammals, museums, reptiles, reviews

A Trio of Tyrants

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

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

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

Gorgosaurus at AMNH

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

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

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

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

Gorgosaurus libratus – USNM 12814

gorgo

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

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

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

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

Gorgosaurus sp. – AMNH 5458

albertosaurus

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

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

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

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

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

Gorgosaurus sternbergi” – AMNH 5664

gorgo sternbergi

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

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

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

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

AMNH 5027 was restored and remounted in 1995.

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

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

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

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

References

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

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

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

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

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

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

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

Permo-Triassic Synapsids at NMNH

Click here to start the NMNH series from the beginning.

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

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

Layout of the USNM east wing, circa 1963.

Layout of the NMNH east wing as of 1963.

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

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

The Dimetrodon

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

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

Note short tail

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

Dimetrodon first displaed on north wall

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

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

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

dimetrodon

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

Dimetrodon in 2014. Photo by the author.

Dimetrodon after the 1981 renovation. Photo by the author.

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

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

The Thrinaxodon

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

Thrinraxodon with Cynognathus skull

Thrinaxodon paired with Cynognathus skull. Photo by the author.

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

Since the 1970s, the Thrinaxodon has been displayed alongside the skull of Cynognathus crateronotus (USNM 22813), which Hotton collected on the same expedition. Both are members of the cynodont clade, which includes some of the closest relatives of modern mammals.

 The Daptocephalus

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

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

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

Photo by Christian Kammerer

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

Back at the museum, Nicholas Hotton prepared the specimen (USNM 299746) and determined it to be Daplocephalus leoniceps, one of the plethora of dicynodonts known from the Beaufort Group. Based on this classification, he reconstructed the badly damaged skull to resemble more complete Daplocephalus specimens, and added casts of Daplocephalus limbs. As it turns out, however, USNM 299749 is not a Daplocephalus – it is a somewhat distantly related dicynodont currently called Odontocyclops (also subject to change). To varying degrees, fossil mounts are hypotheses made of bone and plaster. They are based on the best information available at the time, but sometimes they need to be corrected. The NMNH “Daplocephalus” has been mislabeled and erroneously reconstructed for many years, but the current renovation of the NMNH fossil halls now presents an opportunity to deconstruct the specimen and study it up close.

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

References

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

Kammerer, C. (2015). Personal communication.

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

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

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

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

Fossil sandboxes are terrible

Are these kids learning yet?

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.

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

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.

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

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.

Fancy fisheye photo.

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.

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.

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.

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.

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.

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

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.

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.

Modern photo by the author.

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

Bully for Camarasaurus

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.

In 1903, Elmer Riggs of the Field Museum of Natural History (then called the Field Columbian Museum) underwent a survey of sauropod fossils held at various east coast museums and concluded that the names Apatosaurus and Brontosaurus had been applied to the same animal. Riggs’ treatment, however, was also somewhat incomplete. The unsung hero of the story is Charles Gilmore, whose thorough 1936 monograph on Apatosaurus should have put the admittedly catchier junior synonym to rest for good.

This is not a Camarasaurus skull.

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

Enter the mustache-twirling villain of turn of the century paleontology, Henry Osborn. The founder of the American Museum of Natural History Department of Vertebrate Paleontology and eventual director of the museum at large, Osborn had a detestable social and political agenda and was generally a bit of a jerk. However, he was also the veritable king of American paleontology during his tenure, and his word was generally the last. As such, when the DVP prepared to unveil the world’s first mounted sauropod skeleton in 1905 (pictured above), Osborn insisted that it be labeled “Brontosaurus”, not Apatosaurus. Osborn was definitely aware of Riggs’ taxonomic work and his reasons for ignoring it may be lost to history. Regardless, by calling the first-ever display of a giant dinosaur skeleton “Brontosaurus”, Osborn ensured that the name would be cemented in the public consciousness forevermore.

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 the invalidity of the name “Brontosaurus,” 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 Brontosaurus

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 (by the same AMNH field crew that was collecting fossils for the 1905 “Brontosaurus” mount). What Marsh had instead were 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 the venerable 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. As mentioned, it was Osborn and the rest of the vertebrate paleontology staff at AMNH that built the original “Brontosaurus” mount (AMNH 460), six years after Marsh’s death in 1899.

Counterclockwise from top:

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

Preparator Adam Hermann oversaw the construction of the skeleton, combining 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 sculpt 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 certainly isn’t out of the question 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

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 western Utah quarry that is now Dinosaur National Monument, excavating the most complete Apatosaurus skeleton yet found (CMNH 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 itself 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 casted 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 P25112) 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 museum administrators refused to pay 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 casted 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 Apatosaurus mount was built at the Yale Peabody Museum of Natural History in 1931, using Marsh’s original “Brontosaurus” holotype (YPM 1980) and a lot of plaster padding. The skull this mount originally sported (second 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).

A postcard

The Peabody Apatosaurus 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 this animal. In 1981, McIntosh himself replaced the head of the Peabody Museum Apatosaurus with a cast of the Carnegie skull. AMNH, the Field Museum, and the Carnegie Museum followed suit before the decade was out.

aess

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 ApatosaurusJournal 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 BrontosaurusScience 22:560:374-376.

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

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