Category Archives: reptiles

March 26, 2013 · 3:18 pm

Another JP4 Feathers Post

Okay, I’ll bite.

A week ago, Jurassic Park 4 director Colin Treverrow tweeted two words and a hashtag that set the corners of the internet I hang out in aflame for days afterward. The dinosaurs in the upcoming third sequel will not have feathers, in defiance of the twenty years of irrefutable fossil evidence that has come to light since the original film’s 1993 release. Reactions to this news demonstrate a clear divide among dinosaur enthusiasts: there are those who hate the idea of scientifically inaccurate dinosaurs appearing in mass media, and those who are enamored with the “classic” dinosaurs of their youth, and vocally resist any change. And in this case, I don’t really agree with either.

The problem is that dinosaurs straddle two different roles in our culture. There is the scientific reality of their existence, informed by careful scrutiny of hard evidence. Brilliant researchers collect and interpret fossils, broadening our understanding of not only the lives of dinosaurs, but how life on earth evolves and adapts to change in general. As a science educator, this is the perspective on dinosaurs I am usually invested in.

But dinosaurs also have what John Conway calls “awesomebro” appeal. From this angle, dinosaurs are appealing because they are monsters with big teeth and are generally super cool. This is coupled with an innate association of dinosaurs with early childhood that people are remarkably protective of. For example, on Brian Switek’s 10 Dinosaur Myths that Need to Go Extinct article for Tor Publishing, commenter Alan B. declares “I don’t care what anyone says, the dinos we learned about when I was in grade school were awesome! And given a choice between factual and awesome, I will choose awesome every time!” Clearly there is a a bit of tongue-in-cheek humor at play here, but comments like this appear virtually anywhere feathered dinosaurs are discussed. Many people genuinely care about their “classic” dinosaurs, and react negatively to new discoveries that threaten the dinosaur paradigm they associate with childhood bliss.

As Conway points out, the typical reaction of anyone with a vested interest actual scientific paleontology is to reject and belittle pop-culture dinosaurs whenever possible. Unfortunately, this we’re-right-and-you’re-wrong approach veers into deficit model territory, and doesn’t seem to accomplish much other than make the rift among dinosaur enthusiasts more antagonistic. It makes our audience of potential learners defensive, even angry, that scientists are “ruining” dinosaurs. And focusing conversations on the fact that popular conceptions of dinosaurs are wrong removes focus from the real benefits of researching past life.

I think it would be more helpful to recognize the validity and significance of pop-culture dinosaurs, but to work towards separating them in the public consciousness from real dinosaurs. A potential conversation: You think the Jurassic Park Raptors are cool? Great, so do I, but I think they’re cool in the way other movie monsters like the Predator or the T-1000 are cool. But perhaps you’d be interested in learning about the real animal Velociraptor mongoliensis that the movie Raptors were inspired by? My point is, the widespread appreciation/nostalgia for pop-culture dinosaurs (or fantasy dinosaurs, or classic dinosaurs, or awesomebro dinosaurs, whatever you want to call them) is potentially valuable, but I think it often gets dismissed too gruffly. If would-be educators are outright dismissing what their audience is bringing to the conversation, that audience has little incentive to learn more.

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Filed under dinosaurs, education, movies, opinion, reptiles, science communication

Tagged as deficit model, dinosaurs, Jurassic Park, science communication, Velociraptor

March 18, 2013 · 4:45 pm

A Visit to the Academy of Natural Sciences

I spent yesterday in Philadelphia, my first visit in at least 10 years, and of course made a point of visiting the Academy of Natural Sciences. Founded in 1812, the Academy is the oldest natural science research institution and museum in North America, established “for the encouragement and cultivation of the sciences, and the advancement of useful learning.” Initially formed as a hub for research on the American frontier, the Academy has sponsored scientific expeditions across the world and has amassed a collection of 17 million specimens that is still actively used 200 years after its founding.

In 1868, the Academy museum made a landmark contribution to paleontology by hosting the first mounted dinosaur skeleton ever constructed. The mount, the work of paleontologist Joseph Leidy and sculptor Benjamin Waterhouse Hawkins, depicted Hadrosaurus foulki, the first dinosaur discovered in North America and at the time the most complete dinosaur ever found. With only two limbs, a section of the spinal column and some other odds and ends to work with, Hawkins invented many of the mounting techniques that are still in use today. 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 most of the vertebrae using extant animals as reference. By modern standards, the Leidy-Hawkins Hadrosaurus mount wasn’t especially accurate (the sculpted scapulae and vertebrae resemble those of a mammal, not a reptile; the skull, based on that of an iguana, turned out to be completely off the mark; the fully upright, kangaroo-like posture is now known to be anatomically implausible), but it nevertheless presented the first-ever opportunity to stand in the presence of a dinosaur. Extinct animals were already known to the public, and some had even been mounted, but the Hadrosaurus was so bizarre, so utterly unlike anything alive today, that it really opened people’s eyes to the unexplored depths of the Earth’s primordial history.

Original 1868 Hadrosaurus mount.

The Hadrosaurus display caused public visitation to skyrocket, prompting the Academy to relocate in 1876 to a larger building in central Philadelphia, where it remains today. I haven’t been able to find any photographs or detailed information about it, but for much of the 20th century the Academy had a fossil exhibit with a Corythosaurus mount as its centerpiece. This was replaced in 1986 with an expanded “Discovering Dinosaurs” exhibit, which apparently was among the first to showcase the discoveries of the dinosaur renaissance. This exhibit has just about zero web presence, as well (seriously, any help tracking down details about it would be greatly appreciated). The current version of the Dinosaur Hall opened in 1998, and is what I will discuss below.

This cast of the AMNH Tyrannosaurus is the centerpiece of the Dinosaur gallery. Source: Wikipedia Commons.

What’s Cool

Although crammed into a fairly small space, the Academy’s two-level Dinosaur Hall is packed with mounts of North American fossil reptiles, including Tyrannosaurus, Chasmosaurus, Deinonychus, Tylosaurus, Pachycephalosaurus and many more. Compared to the sterile and coldly scientific displays at larger museums like the American Museum of Natural History, the Academy’s exhibit designers clearly put an emphasis on accessibility, particularly for younger visitors. Signs are attractive, colorful and use simple language, but do not sacrifice scientific accuracy. Although “Do Not Touch” notices abound, guardrails are low and allow visitors to view the mounts up close. Even the fossil prep lab, a staple in paleontology exhibits, is not behind glass but is separated from visitors by a low wall, allowing guests to converse freely with the preparators if they so choose (This might not be so fun for the preparators; I’ve worked in a couple of these labs and I’ll be the first to admit that our conversations are not always for public ears).

The Academy’s Dinosaur Hall is also filled with interactive activities. I question the educational value of a green-screen that places visitors into a scene with dinosaurs running around (the last thing we need is to encourage more people to think humans and dinosaurs coexisted), but many of the other interactives are quite inspired. In one corner, children are encouraged to climb inside a Tyrannosaurus skull cast to find evidence for its diet and lifestyle. Crouching between its jaws, kids find partially-erupted teeth, evidence that the predator broke and regrew teeth throughout its life. My favorite interactive, however, featured parallel rows of theropod and crocodile footprints on the floor. Visitors were directed to walk down each trackway, comparing how it felt different to move with an upright or sprawling gait. At the end, a sign explained that it’s harder, and less energy efficient, to move like a crocodile. I loved this activity because it was simple (just images on the floor, no technology required) and yet conveyed a clear explanation of biomechanics. Visitors use their own bodies to reach the conclusion, finding the answer in a tactile and experiential way that is more memorable than just being told that a sprawling posture is inefficient.

Overall, the Dinosaur Hall is a great overview of dinosaur science. It focuses on the biology of dinosaurs, emphasizing their similarity to animals we know today, and how scientists can draw conclusions about past life by studying the modern world. This content is communicated in a way that is clear and engaging for visitors of all ages, making this exhibit a good example of the old adage that all good science can be explained in simple terms. When I visited, there were a couple children using the open exhibits like a playground, but for the most part I think this highly accessible dinosaur exhibit is quite successful.

What’s Not So Cool

The Academy’s Dinosaur Hall is 15 years old, and is in some places showing its age. Some of the exhibit content is not entirely up-to-date; for instance, a display on the relationship between birds and dinosaurs leaves the question completely open ended. I also saw at least two invalid names, “Majungatholus” and “Ultrasauros”, used on labels. Probably more obvious to most visitors is the general wear and tear visible in certain parts of the exhibit. Some labels, particularly those facing large windows, are badly faded. The Elasmosaurus mount was moved from the Dinosaur Hall proper to the entrance lobby at some point, but Elasmosaurus signage, now labeling an empty space, is still in place in the exhibit. I got the impression that the Academy, like much of Philadelphia, is hurting for funding.

Corythosaurus and Chasmosaurus mounts. Source: TravelMuse.

The story of Leidy’s Hadrosaurus appears in several places throughout the museum. Casts of the original fossil material are displayed over a silhouette of the dinosaur toward the back of the Dinosaur Hall. Elsewhere , there is a new full casted mount of Hadrosaurus (signs explain that it is filled in with Maiasaura material), and the original tibia is displayed as part of a rather cool 200th Anniversary special exhibit. At the time, I wished that these displays were consolidated in one place, since the Hadrosaurus story is an important chapter in the history of science and of museums that can be seen exclusively at the Academy. I later found out that in 2008, the Academy had a major temporary exhibit commemorating the 150th anniversary of the original Hadrosaurus mount, which featured, among other things, a recreation of the victorian-era exhibit and the workshop of Benjamin Waterhouse Hawkins (great videos and interviews about the exhibit here). I wish I had been able to see that, because it blends the scientific, cultural and historic value of fossil mounts in a way that only this museum can.

The sadly closed Hadrosaurus Anniversary exhibit. Note Hawkins’ original sculpted head on the red pillow. Source: The Art Blog.

The current centerpiece of the Dinosaur Hall is a cast of the AMNH Tyrannosaurus. It’s neat, but I imagine most visitors would be more enthused to see the real one just a couple hours down the road. Indeed, most of the dinosaurs on display at the Academy are casts from other institutions. I have no problem with displaying casts, but I can’t help but feel that this generalized dinosaur exhibit is underselling the Academy’s own fossil collections, not to mention its contributions to paleontology. Should the Academy renovate this space again, I’d love to see the institutions’ unique history play a more prominent role, as well as the work that Academy-affiliated researchers are doing today.

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Tagged as Academy of Natural Sciences, dinosaurs, Hadrosaurus, history of science, museums, natural history museums, paleontology

January 8, 2013 · 8:28 pm

Extinct Monsters: Murals and Dioramas

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

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

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

The Life-Sized Models

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

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

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

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

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

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

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

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

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

The Murals

The first dedicated prehistoric mammal exhibit at NMNH opened in the summer of 1961. Alongside the array of Cenozoic fossil mounts, the exhibit featured four brand new murals created by paleoartist Jay Matternes (he painted two more for the Ice Age hall several years later). Still active today, Matternes is a prolific artist of both modern and prehistoric wildlife. In addition to the NMNH murals, Matternes has contributed to exhibits at the American Museum of Natural History and the Cleveland Museum of Natural History, as well as numerous publications including National Geographic Magazine.

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

Oligocene and early Miocene murals, as seen in the 1985-2014 iteration of the exhibit, Mammals in the Limelight. Photo by the author.

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

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

The “Life in the Ancient Seas” exhibit debuted in 1990 with a monumental 130-foot mural by Eleanor Kish. From the explosion of invertebrate diversity in the Cambrian to the proliferation of aquatic mammals in the recent past, the mural spans 541 years of deep time. The project took Kish two years to complete and is, simply put, a masterpiece. Within the exhibit, this meticulously crafted image defines the space’s layout and color palate. It visually separates concepts and themes, and even directs visitor traffic with its strong leftward momentum.

The Dioramas

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

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

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

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

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

Cretaceous diorama by Norman Deaton. Source: flickr.

Cretaceous diorama by Norman Deaton. Photo by the author.

Triassic diorama by Norman Deaton. Source

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

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

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

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Filed under dinosaurs, Extinct Monsters, history of science, mammals, museums, NMNH, paleoart, reptiles, science communication

Tagged as dinosaurs, dioramas, Extinct Monsters, museums, natural history museums, NMNH, paleoart, paleontology, science communication, Smithsonian

September 23, 2012 · 9:10 am

Extinct Monsters: The Marsh Dinosaurs, Part II

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

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

The Ceratosaurus

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

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

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

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

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

The Camptosaurus

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

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

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

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

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

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

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

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

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

The Stegosaurus

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

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

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

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

Cast of Stegosaurus and Camptosaurus. Photo by the author.

Casts of Stegosaurus and Camptosaurus. Photo by the author.

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

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

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

References

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

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

Jabo, S. 2012. Personal communication.

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

Tagged as Camptosaurus, Ceratosaurus, dinosaurs, fossils, museums, National Museum of Natural History, Smithsonian, Stegosaurus

July 16, 2012 · 4:47 am

Extinct Monsters: Gilmore’s Diplodocus

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

More than 80 years ago, Smithsonian paleontologist Charles Whitney Gilmore supervised the installation of the mounted Diplodocus skeleton known as USNM 10865. In December 2014, that same skeleton was finally disassembled for conservation and eventual re-mounting.This post is about the history of this particular mount: where it came from, who put it together, and what it has and continues to tell us about prehistory.

Predecessor at CMNH

The story of the NMNH Diplodocus mount actually began in Pittsburgh, Pennsylvania around the turn of the century. In November of 1898, Steel tycoon-turned-philanthropist Andrew Carnegie read that the remains of a giant “Brontosaurus” had been discovered in Wyoming. Carnegie’s interest was piqued and the following year, he contributed $10,000 to the Carnegie Museum of Natural History (which he had founded two years earlier) to find a complete “Brontosaurus” – or something like it – for display in Pittsburgh. Perhaps proving that money can indeed buy anything, on July 4th, 1989 the CMNH team found a reasonably complete sauropod skeleton in Sheep Creek Basin, Wyoming. CMNH Curator of Paleontology John Bell Hatcher declared the specimen to be a new species, which he named for the Museum’s benefactor: Diplodocus carnegii.

Back in Pittsburgh, the task of preparing and mounting the fossils fell to preparator Arthur Coggeshall and his staff. Creating a permanent armature for a delicate 84-foot skeleton was a monumental undertaking, beyond anything that had ever been attempted before. Coggeshall used a steel rod, shaped to the contours of the vertebral column, as the basis for the mount. Once the backbone was in place, the limbs, ribs, and other extremities were mounted on steel rods of their own and attached to the rest of the skeleton. The fossils were connected to the steel armature by drilling screws and bolts directly into the bone. Since the original Diplodocus carnegii skeleton was not complete, the mount was supplemented with fossils uncovered during subsequent field seasons at Sheep Creek and elsewhere in Wyoming.

The CMNH Diplodocus was unveiled in 1907 in a brand-new wing that had been constructed to display it. Although the American Museum of Natural History had by that point completed a sauropod mount of their own, the Pittsburgh display was well-received by paleontologists and laypeople alike. Not to be bested by the New York competition, Carnegie also commissioned eight Diplodocus replicas, which he donated to museums throughout Europe and Latin America.

The original CMNH Diplodocus mount, in the hall built specifically to accomodate it. Source

The original CMNH Diplodocus mount, in the hall built specifically to accommodate it. Source

This wave of publicity allowed the paleontology staff at CMNH and elsewhere to continue to undergo large-scale fossil hunting expeditions. In 1909, a team led by Earl Douglass hit the jackpot north of Jensen, Utah. At the site now known as Dinosaur National Monument, CMNH teams excavated over 300 tons of Jurassic fossils over 13 field seasons. The immensely productive “Dinosaur Quarry” site is thought to represent a prehistoric river bar, where dead animals from upsteam accumulated over time. In addition to an assortment of crocodiles and other small reptiles, this location has yielded remains of Apatosaurus, Diplodocus, Stegosaurus, Allosaurus and many other taxa. Although the site was far from exhausted, the CMNH team moved on in 1922, at which point paleontologist Charles Gilmore from the United States National Museum took over.

USNM Excavation at Dinosaur National Monument

Gilmore led the first USNM field season at Dinosaur National Monument in May of 1923. In their final year at the site, the CMNH team had located two partial sauropod skeletons. Gilmore opted to focus on excavating these “in order to secure a mountable skeleton” for display (Gilmore 1932). As with the CMNH team before them, the primary motivation of Gilmore’s team was not scientific research, but to bring back spectacular display specimens. Gilmore was unarguably a phenomenal scientist who made lasting contributions to our knowledge about prehistory, but this focus on impressive displays was typical of early 20th century paleontology. As such, valuable taphonomic and ecological data that would been collected by modern paleontologists was probably destroyed when unearthing this and other exhibition-caliber dinosaur specimens.

Once the excavation began, Gilmore decided that the Diplodocus skeleton dubbed specimen 355 was the best candidate for a mount. The skeleton consisted of an articulated vertebral column, from the 15th cervical to the 5th caudal, a separated but virtually complete tail, the pelvis, both pectoral girdles, much of the rib cage, both humeri, and a complete left hind limb. Unfortunately, the head and most of the neck had eroded out of the hillside and long since weathered away. Some elements not preserved with specimen 355 were reportedly cherry-picked from another specimen at the same site. Again, this sort of selective excavation is discouraged today, but was typical at the time. On August 8, the team wrapped up and shipped 25 tons of material back to Washington, DC via railway.

Preparation, Mounting and Description

Preparing and mounting the Diplodocus was, according to Gilmore, the single most ambitious undertaking attempted by the department during his tenure. In his words, “the magnitude of the task, by a small force, of preparing one of these huge skeletons for public exhibition can be fully appreciated only by those who have passed through such an experience” (Gilmore 1932). Gilmore, along with preparators Norman Boss, Thomas Horne, and John Barrett, spent 2,545 working days over the course of six years preparing the skeleton for exhibition. Gilmore reported that his team followed the method Arthur Coggeshall had developed at CMNH over 20 years earlier for mounting their sauropod. The vertebral column was assembled first, supported by a series of steel rods. This structure was mounted at the appropriate height on four upright steel beams securely anchored to the floor. Limbs and other extremities were subsequently added, with steel rods shaped to the contours of the fossils supporting each portion of the skeleton.

Diplodocus under construction, ca. 1930. Source

Missing parts of the skeleton, including the right hindlimb and the distal portions of the forelimbs, were filled in using casts of the Carnegie Diplodocus. According to Gilmore, the casted elements were colored “to harmonize with the actual bones but with sufficient difference to be at once distinguished from the originals” (Gilmore 1932). This is noteworthy, because the creators of other dinosaur mounts at that time had been known to deliberately disguise artificial elements by painting them to match the fossils. Although the Smithsonian Diplodocus was a composite of multiple specimens and therefore does not represent any single animal that actually existed, the decision to make the casted elements readily visible represents a degree of honesty and integrity that is more common in modern museum displays than it was in Gilmore’s time.

Gilmore presents plans for the in-progress Diplodocus mount at the 1927 Conference of the Future of the Smithsonian. Photo courtesy of the Smithsonian Institution Archives.

In the process of preparing and mounting the Diplodocus (at this point designated USNM 10865), Gilmore was able to further refine our understanding of sauropod physiology. Looking at the specimen, Gilmore was easily able to dismiss notions by earlier workers that Diplodocus had sprawled like a crocodile, asserting that “the crocodilian attitude for Diplodocus involves anotomical imposibilities” (Gilmore 1932). Additionally, since the entire dorsal portion of the vertebral column was present and intact, Gilmore determined that the presacral vertebrae (in the lower back) arch downward, toward the sacrum. The CMNH Diplodocus and AMNH Apatosaurus had been mounted with completely straight backs, so Gilmore was able to create a more accurate mount. Studying the articulated vertebral column also convinced Gilmore to raise the tail higher than in previous sauropod mounts. Although it would be decades before paleontologists started raising the tail completely clear of the ground, this was certainly a step in the right direction. Gilmore refrained, however, from definitively assigning USNM 10865 to a particular species of Diplodocus, since at the time (and to this day, apparently) the differences among the named species of this genus were unclear.

Exhibition and Legacy

USNM 10865 in the Hall of Extinct Monsters, circa 1932. Photo courtesy of the Smithsonian Institution Archives.

The completed Diplodocus skeleton was 70 feet, 2 inches long and 12 feet, five inches tall at the hips, making it about 14 feet shorter in length than its CMNH counterpart. The mount was introduced to the Hall of Extinct Monsters at the United States National Museum in 1931, positioned atop three pedestals so that visitors could walk right underneath it. The Diplodocus was placed right in the center of the gallery, facing west so that it could stare down visitors as they entered the hall.

The unveiling of the Diplodocus mount was a big deal, but did not catch the public’s attention in quite the same way as its CMNH predecessor. After all, by 1931 several of the other major natural history museums had had sauropods on display for over two decades. Nevertheless, for residents and visitors in Washington, DC the new mount was an unforgettable look at the life of the past.

The Diplodocus, as it stood from 1963 through 1981. Image courtesy of the Smithsonian Institution Archives.

The Diplodocus was not moved during the 1963 modernization of the fossil exhibits, but the walkable area around the mount was significantly reduced. Visitors could no longer walk under the skeleton, or get as close to it. The Diplodocus was not moved during the 1981 renovation, either, but the neck support coming up from the floor was replaced by less intrusive cables suspended from the ceiling. In the new exhibit, the sauropod centerpiece was surrounded by contemporaneous friends from the Morrison Formation, including Stegosaurus, Camptosaurus, Camarasaurus and Allosaurus.

National Museum of Natural History in Washington, DC.

Diplodocus as it stood from 1981-2014. Photo by the author.

From 1931 to 2014, the Diplodocus remained an unchanging fixture of the Museum’s east wing. Although this specimen’s story has not been as widely told as that of the CMNH Diplodocus, the Smithsonian sauropod is certainly just as interesting. For more than 80 years, USNM 10865 has mesmerized generations of viewers with its size and elegance. What’s more, this specimen, and the associated measurements and drawings meticulously prepared by Gilmore, are frequently referred to in publications by modern paleontologists. For its contributions to public education and to scientific inquiry, USNM 10865 is one to celebrate.

References

Brinkman, P.D. The Second Jurassic Dinosaur Rush: Museums and Paleontology in America at the Turn of the 20th Century. Chicago: University of Chicago Press, 2010.

Gilmore, C.W. “On a Newly Mounted Skeleton of Diplodocus in the United States National Museum.” Proceedings of the United States National Museum 81:1-21, 1932.

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

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

Tagged as dinosaurs, diplodocus, museums, natural history museums, Smithsonian

July 11, 2012 · 8:56 am

Extinct Monsters: History of Smithsonian Fossil Exhibits

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

Upon his death in 1829, British scientist James Smithson left his fortune to the United States government to found “at Washington…an establishment for the increase and diffusion of knowledge.” Congress used Smithson’s estate to establish the publicly funded Smithsonian Institution in 1846, which has since grown into an expansive research institute and museum complex that is recognized the world over. Vertebrate paleontology has been an important part of the Smithsonian’s agenda since the beginning, and this article by Ray Rye provides a compelling history of the scientific staff and their research. This post will take a slightly different approach, summarizing the changing public face of Smithsonian paleontology in the form of its genre-defining exhibits.

In 1847, Joseph Henry, the Smithsonian’s first secretary, started construction on the original Smithsonian building, which today is colloquially known as “the castle.” The first vertebrate paleontology exhibit housed within its walls consisted of a trio of casted skeletons: the ground sloth Megatherium, the glyptodont Scistopleurum, and the tortoise Collossochelys. These exhibits were probably obtained through Ward’s Natural Science Establishment. The Smithsonian’s first skeletal mount made from original fossils was a Megaloceros, purchased from antiquities dealers Thomas and Sons in 1872.

Exhibits like this one at USNM were deemed incomprehensible and inspired early reform

Basilosaurus, Megatherium, and Megaloceros are visible in the southwest court of the first United States National Museum. Image courtesy of the Smithsonian Institution Archives.

1881 saw the completion of the original United States National Museum, next door to the castle (this structure is now called the Arts and Industries Building). The southwest court was dedicated to osteology and paleontology, and the existing skeletal mounts were placed here among rows of cases containing smaller specimens. At this point in time, the Smithsonian had very few permanent staff members, instead relying mostly on scholars serving in unpaid “honorary” positions to curate the growing national collection. Famed paleontologist O.C. Marsh (the beardier half of the “bone wars” rivals) was the honorary curator of vertebrate paleontology. Under contract with the United States Geological Survey, Marsh supervised numerous field expeditions to the American west and oversaw the collection of untold thousands of fossil specimens. When Marsh died in 1899 the fossils he collected for the government were relocated from Yale University (his home institution) to the Smithsonian.

Gilmore and the Hall of Extinct Monsters

C.W. Gilmore with some Diplodocus vertebrae. Image courtesy of the Smithsonian Institution Archives.

Charles Whitney Gilmore was a student in mine engineering at the University of Wyoming when he became involved in the Carnegie Museum’s fossil hunting expeditions in 1899. Recognizing the young man’s enthusiasm and talent, John Bell Hatcher hired Gilmore immediately after his graduation in 1901. Gilmore worked with Hatcher for two field seasons, but in 1903 he moved to Washington, DC upon being offered a position as a full-time preparator at the USNM. He was promoted to Curator of Vertebrate Paleontology in 1924, and is fondly remembered as an exceptionally modest but extraordinarily productive scientist. As curator, Gilmore led sixteen fossil-hunting expeditions to the western interior. Gilmore’s most enduring contribution to paleontology, however, is his extensive body of descriptive publications on the Marsh fossils. His monographs on Apatosaurus, Camarasaurus, Ceratosaurus, and many others are still regularly cited today.

Along with preparators Norman Boss and James Gidley, Gilmore is responsible for creating most of the mounted dinosaur skeletons that are on display at the Smithsonian. The first dinosaur mount Gilmore and his team completed was Edmontosaurus, which went on display in the original USNM building in 1904. Gilmore would go on to supervise the construction of Triceratops (the first mount of this taxon in the world), Camptosaurus, Stegosaurus, Dimetrodon, Ceratosaurus, Diplodocus, and numerous other displays that have been enjoyed by generations of museum visitors.

The Hall of Extinct Monsters, sometime before 1929. Image courtesy of the Smithsonian Institution Archives.

Congress authorized the construction of a new United States National Museum on the north side of the National Mall in 1911. In contrast to the Victorian style of the original building, the new museum sported neoclassical granite construction which matched the aesthetic of the other federal buildings. Exactly when the museum opened is the subject of some debate. Collections and offices began moving across the mall via horse and wagon in 1908, and part of the first floor opened to the public on March 17th, 1910. Nevertheless, it was not until 1911 that all the exhibit spaces were ready for visitors, including the evocatively titled “Hall of Extinct Monsters” in the museum’s east wing. This cavernous space devoted to fossil displays was primarily under Gilmore’s stewardship, and generally resembled a classic “cabinet of curiosity” approach to exhibit design. Gilmore and his team would gradually fill the Hall of Extinct Monsters will new specimens over the coming decades, culminating in the towering Diplodocus mount completed in 1932.

Modernization and Renaissance

Gilmore retired in 1945, and vertebrate paleontology research at the USNM, particularly in dinosaurs, quieted in his absence. Charles Gazin, Gilmore’s successor as Curator of Vertebrate Paleontology, specialized in mammals, and the museum remained without a curator specializing in dinosaurs until Matt Carrano was hired in 2003. In 1957, the USNM split into two subdivisions, the Museum of Natural History and the Museum of History and Technology. The Smithsonian’s history collections were moved to a new building next door, now called the National Museum of American History, and other collections gradually dispersed into 20-some other Smithsonian museums. The site of the disbanded USNM was officially renamed the National Museum of Natural History in 1967, and remains the home of natural sciences and anthropology.

The Hall of Fossil Reptiles lasted from 1962 to 1981. Image courtesy of the Smithsonian Institution Archives.

The Hall of Extinct Monsters persisted largely unchanged until 1962, when it was finally renovated as part of a Smithsonian-wide modernization project. The fossil exhibits were among the last to be updated, in part due to ambivalence from the paleontology curators. The department did not employ any staff members exclusively devoted to exhibit work, so the task of reinventing the displays was an added burden for the research staff. As such, the changes to the hall ended up being more cosmetic than structural. The largest mount, Gilmore’s Diplodocus, was too difficult to disassemble and move, so the new exhibit was designed around it. Solid earth tones and wall-to-wall carpet replaced the original neoclassical aesthetic. The John Elliot mural Diana of the Tides, positioned high on the east wall, was simply boarded over during construction (and has remained so ever since).

The 1981 renovation saw the addition of a mezzanine over the dinosaur exhibit. Source

In 1974, the addition of the Hall of Ice Age Mammals and the Rise of Man expanded the paleontology display space beyond the east wing. Further renovations took place in three stages starting in 1979. Entitled “Fossils: The History of Life”, the overhauled exhibit complex represented a significant departure from earlier iterations of this space. While the previous renovation arranged specimens according to taxonomy and curatorial specialties, “The History of Life” followed the evolutionary progression of fossil plants and animals through time. The new exhibits also differed from prior efforts in that they were not put together exclusively by curators. Instead, the design process was led by educators and exhibits specialists, who sought curatorial input at all stages. The new specimens and displays also required the once spacious hall to be carved up into a maze of small rooms and narrow corridors. Even with the additional floor space provided by a new balcony over the dinosaurs, the east wing had become quite crowded.

Of course, the science of paleontology has advanced by leaps and bounds since the 1980s, and NMNH staff have made piecemeal updates to the exhibits when possible. These changes include restorations of deteriorating mounts, the addition of a cast of Stan the Tyrannosaurus, and a few revised signs addressing the dinosaurian origin of birds and new dates for geologic time periods. Still, the east wing remained largely the same for over 30 years, and began to look a bit tired next to the brand-new exhibits that have opened at NMNH over the last decade.

Looking Ahead

The NMNH fossil halls closed on April 27th, 2014 for a five year renovation project. For the first time, the east wing was completely gutted and its underlying infrastructure overhauled. Aging specimens like the 1932 Diplodocus and the 1911 Ceratosaurus were be painstakingly disassembled and conserved, and the space itself was restored to its original Beaux Arts splendor. The re-imagined exhibit is arranged in reverse chronological order: visitors start among mammoths and ground sloths in the Pleistocene and move backward in time through increasingly alien-looking versions of North America. Unlike the present exhibit, however, an open floor plan will allow visitors to get a sense of what they’re in for from the moment they walk into the hall.

Mesozoic section of the new Hall of Fossils – Deep Time. Concept art on display in the Last American Dinosaurs exhibit at NMNH.

The overall theme is change over geologic time, highlighting the myriad ways that climate, geography, evolution, and other living and nonliving systems interact and shape the world’s environments. Not all the classic mounts will make it into the new space (Brachyceratops, Zygorhiza, and Stegomastodon are among the retirees), but there are many new additions, including the Nation’s T. rex. The result will be a compelling mix of classic early 20th century museum aesthetics and modern visitor-focused educational strategies.

References

Gilmore, C.W. (1941). A History of the Division of Vertebrate Paleontology in the United States National Museum. Proceedings of the United States National Museum No. 90.

Rye, R. (2002.) History of the NMNH Paleobiology Department. http://paleobiology.si.edu/history/rye.html

Sues, H. and Marsh, D. (2013). Charles Whitney Gilmore: The Forgotten Dinosaur Hunter. http://paleobiology.si.edu/history/gilmore.html

Yochelson, E.L. (1985). The National Museum of Natural History: 75 Years in the Natural History Building. Washington, DC: Smithsonian Institution Press.

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

Tagged as dinosaurs, Extinct Monsters, fossil mounts, fossils, museums, natural history museums, paleontology, Smithsonian

June 20, 2012 · 9:41 am

Communicating Systematics, Part 2

In the previous post, I discussed how phylogenetic trees, while powerful and informative to trained eyes, can be misinterpreted by lay audiences. These misunderstandings are easy to diagnose, but actually finding solutions to the problem is challenging.

In a perfect world, every child would be introduced to evolutionary theory early and often in their obligatory science education, and everybody would be able to interpret phylogenetic trees the way scientists do. This is unlikely to happen anytime soon, especially in the United States, so educators are going to have to get creative. One option is to provide additional information to aid in the interpretation of the diagram. On the surface, adding more information is always an attractive prospect, but unfortunately it does not always work as intended. Attention spans are perilously short, and the goal of a visual representation should be to make the content immediately intuitive and easier to understand.

If conventional shapes and symbols in evolutionary trees are not getting the intended message across to target audiences, then perhaps we need to rethink how we are structuring these trees. I don’t have a catch-all solution, but the following might be enough to at least start a conversation.

Change the shape of the tree

Torrens and Barahona argue that many misinterpretations of trees stem from ideas of essentialism and teleology that are deeply ingrained in and continually reinforced by western culture. Likewise, equating up with good and down with bad is a recurring, internalized motif. Therefore, trees that illustrate evolution and diversification proceeding upward or to the right only encourage presuppositions of linear, goal-oriented evolution.

One solution that has been experimented with (at AMNH, for example) is to draw trees as circles (see below). This eliminates the problem of associating up with good and bad with down, or upward movement with progress. A circular “tree” has no orientation, and thus does not imply any taxa to be better than the rest. Personally, I find circle diagrams confusing to read, but I appreciate what they are intended to accomplish. A diagram of evolutionary relationships could theoretically take any shape, since the crucial information is in the branching order, not the nature of the lines.

A circular tree. From eplanetscience.com.

Be careful with representation of ancestors

Many phylogenetic diagrams place specific fossil taxa at nodes along the tree in order to illustrate the course of evolution. This is informative of general evolutionary trends, but it can also be confusing. As a case in point, I just did an image search for a horse evolution diagram to use as an example, and found that many of the top results came from creationist websites. These sites aren’t worth linking to (although they are easy enough to find), but they erroneously assume that fossil taxa are thought to be directly ancestral to modern Equus caballus. Evolutionary scientists think no such thing, but looking at the image below I can see how that conclusion could be reached.

This diagram of the evolutionary history of horses can lead to the mistaken assumption that earlier species are thought to be directly ancestral to later ones. That polytomy that leads to three unlabeled nodes doesn’t help either.

In a proper cladogram, taxa are only placed at the ends of branches. Direct ancestry is (almost) never inferred, because the scarcity of the fossil record prevents us from ever knowing exactly what evolved into what when. The cladogram below shows the relationships between the seven modern-day species of Equus. Systematists have determined a series of branching relationships based on anatomical and molecular data, and even provide a suggestion of when these divergences occurred, via the time scale. Each node represents a common ancestor that definitely existed, but we will probably never find or identify their fossils.

A cladogram of modern horse species. From Hooper Virtual Natural History Museum.

In this case, I would prefer if books or exhibits for popular audiences nixed images like the first one and instead went with cladograms that do not suggest specific ancestor-descendant relationships. Obviously the cladogram could be spiced up with colors and illustrations, but it is important to use a format that represents precisely what scientists do and do not know.

Always clarify orientation

Proboscidea phylogeny from academic.reed.edu.

Individuals well-versed in evolutionary science automatically read trees from the basal node out to the tips. Typically, and in the elephant phylogeny above, that would be from the bottom up. It can therefore come as a surprise (it certainly did for me) that non-specialists frequently attempt to read phylogenetic trees from left to right. Viewers may assume that the horizontal order of taxa across the top is significant, representing either the course of evolution or time. Neither would be correct, as Mammut on the far left and Mammuthus on the far right were roughly contemporaneous, and Loxodonta africana and Elephas maximus in the middle are the only extant elephants. Although it may not occur to specialists, it is a simple and necessary precaution to label the orientation of the tree and avoid such confusion.

Avoid calling anything “more evolved”

This is more of a nomenclature issue than a visual one, but poor graphics can exacerbate this misconception. All contemporary species, from sponges to frogs to humans, have been evolving for the same amount of time. An amphibian or reptile is not “primitive”; it is just as adapted to its environment as we are. Using this sort of terminology is attractive as a shortcut when referring to less-diverse sister groups to more-diverse clades, but it misrepresents the nature of evolution and should be discouraged.

References

MacDonald, Teresa E. “Communicating Phylogeny: Evolutionary Tree Diagrams in Museums.” 2010. Paper presented at the NARST (National Association for Research in Science Teaching).

Torrens, Erica and Barahona, Ana. “Why are Some Evolutionary Trees in Natural History Museums Prone to Being Misinterpreted?” 2012 Evolution: Education and Outreach 1-25.

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Tagged as cladistics, evolution, science communication, science education, systematics

June 8, 2012 · 9:55 am

Communicating Systematics

In case you forgot, only 15% of Americans polled by Gallup accept that human beings evolved from other animals through natural processes*. This statistic has not changed meaningfully since Gallup started asking this question in 1982. This fact should be in the back of the mind of every science educator, and for that matter, every scientist, each and every day we go to work. It is a scientifically well-established fact that all life has evolved over long periods of time, and that all forms of life are related to each other. This fact is fundamental to our understanding of life on Earth. The goal of both educators and scientists is to expand our knowledge and awareness of our world, and it is therefore disconcerting that so few people are willing (or have had to opportunity to) acknowledge the wealth of information that an understanding of evolution provides.

*A couple complaints about that link. First, the phrasing of the question, “human beings evolved over millions of years from less advanced forms of life” (emphasis mine) is poor, read on for reasons why. Second, belief that humans evolved “with God’s guidance” does not seem like a meaningful distinction to me, and does not suggest a proper understanding of evolution.

The overwhelming number of people who do not accept evolution is intimidating. The fact that our politicians and leaders are often among this number is even more troubling. It can be tempting to retreat into academia and whine about the problem to our peers, or perhaps ignore it entirely. However, 30 years of unchanging results on the Gallup poll indicate that the issue is not going to go away. Both educators and scientists need to take the offensive and directly address misconceptions and misunderstandings about evolution, as well as find effective means to mitigate them.

Phylogenetic Trees

In the world of science education, one of the trickiest issues is supplying appropriate context. Although all good science can be explained in clear, readily-understandable language, most research still requires some background on the Big Ideas in science. Two huge examples are evolution by natural selection and the scientific method, which I briefly discussed here and here. Without an understanding of how scientific ideas or generated or how evolution works, discussing the finer points of, say, feeding strategies of tyrannosaurs is quite pointless. Unfortunately, even among people who accept the fact that evolution is a real phenomenon, this background all too often does not exist.

Educators need to supply the public with the context they need to understand current science, and one good area to focus is the reading of phylogenetic trees. A phylogenetic tree is a branching diagram that depicts inferred evolutionary relationships among organisms. A tree implicitly shows that included organisms descended and diversified from a common ancestor. As such, phylogenetic trees are a visual embodiment of evolutionary theory, and provide an informative narrative of the history of life.

As is often the case, David Hone has already provided a wonderful explanation of how scientists construct trees and how to read them correctly, so I’ll just drop that link and move on. The problem is that although evolutionary trees are often used to convey ideas in museum displays and general interest science articles, many lay-viewers are interpreting them inaccurately. Reading a tree requires practice and expertise that shouldn’t be taken for granted, because misinterpretations only provide fodder for the anti-evolution/anti-science lobby. Let’s go through the common misinterpretations one at a time (many of these are discussed in Torrens and Barahona 2012, a few are my own additions).

Evolution is goal-oriented. In fact, evolution is not progressive, but is the product of organisms adapting to their specific environment. When that environment changes, taxa that were once well-adapted often die out. Being “well-evolved” is therefore fluid and transitory state. The misconception of directed evolution is probably related to ingrained western religious views of human superiority over nature. Rather annoyingly, cultural anthropologists often buy into the erroneous idea of progressive evolution, and attempt to use it as evidence that science is but one of many equally correct world-views.

There is a “main line” of evolution. This is largely the product of late 19th century drawings of trees of life which used literal trees as the basis of the diagram. Most famously, German natualist Ernst Haeckel illustrated the Systematischer Stammbaum des Menschen in his book Anthropogenie in 1874. In this drawing, the diversity of life is overlaid on a tree, which has a thick trunk running straight up to humans and other primates at the top. Again, this plays into concepts of human superiority and inevitability that have nothing to do with biological evolution.

Some contemporary species are more or less evolved than others. All contemporary species, from sponges to frogs to humans, have been evolving for the same amount of time, and are just as adapted to their environments as we are. Unfortunately, placing humans or mammals at the top or the right of phylogenetic trees seems to be an unshakable habit, even for systematists, which only encourages the notion that these taxa are somehow better.

Similarity among taxa always implies relatedness. Determining evolutionary relationships is a complex process. Modern systematists use huge matrices of independent characters to calculate the most parsimonious trees. Furthermore, Hennigean cladistics requires that relationships only be determined using synapomorphies (shared derived traits) rather than plesiomorphies (shared primitive conditions). Although the salmon and the lungfish below superficially appear more like one another than the cow, similarities like a fishy shape and a lack of a neck are primitive conditions, not specializations. The synapomorphies shared by the lungfish and cow, such as jointed limbs and the ability to breathe air, inform us that they shared a more recent common ancestor than either did with ray-finned fish.

A counter-intuitive cladogram. Subjective similarity does not always mean relatedness.

Change only occurs at nodes. The nodes in a phylogenetic tree do not represent literal evolutionary events. Rather, evolution is a continuous process. This is a case where I like to ask people who make this misconception, “how could we know that?” This can get people thinking about what evidence is available to scientists, what conclusions can be reached from these data, and what isn’t known.

Example taxa illustrated lower in the tree represent direct ancestors of taxa higher in the tree. It can be helpful to use fossil species to illustrate the general state of an evolutionary lineage at varying points in time (this is done all the time with diagrams of horse evolution). However, with few exceptions, the incomplete nature of the fossil record makes it impossible to know exactly which species were directly ancestral to others.

Traditional Linnean categories are directly applicable to trees. In fact, most (sensible) modern systematists prefer the cladistic methodology, which requires that all groups be monophyletic (that is, made up of all descendents of a common ancestor, with no exclusions). For example, the traditonal Linnean definition of reptiles, which includes turtles, lizards, snakes, tuataras and crocodiles, is not monophyletic, because any cladistic unification of these taxa would also have to include birds.

The traditional definition of reptiles, which excludes birds, is paraphyletic.

This went on a bit longer than I expected, so I’m going to leave these issues hanging for the time being. But do not fret, I will finish this train of thought soon with a discussion of potential solutions to these misinterpretations that have been attempted, and some that may be attempted in the future.

References

MacDonald, Teresa E. “Communicating Phylogeny: Evolutionary Tree Diagrams in Museums.” 2010. Paper presented at the NARST (National Association for Research in Science Teaching).

Torrens, Erica and Barahona, Ana. “Why are Some Evolutionary Trees in Natural History Museums Prone to Being Misinterpreted?” 2012 Evolution: Education and Outreach 1-25.

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Tagged as evolution, museums, pictures, science communication, science museums, systematics

May 5, 2012 · 1:10 am

A brief history of mounted dinosaur skeletons

Mounted fossil skeletons, especially those of dinosaurs, are common at medium and large natural history museums. These mounts play a central role in the public’s perception of not only dinosaurs and other prehistoric animals, but of museums as well. However, just as dinosaurs are relatively new to science, fossil mounts have not always been a part of museums. The word dinosaur was coined in 1842 by British anatomist Richard Owen, based on a handful of fragmentary remains of large, extinct reptiles. Nevertheless, the study of dinosaurs did not start in earnest until 1865, when Joseph Leidy of Philadelphia’s Academy of Natural Sciences described Hadrosaurus, the first dinosaur found in the United States, and eventually, the first dinosaur skeleton to be mounted. The western frontier of North America proved to be a richer dinosaur hunting ground than Europe had been, and so vertebrate paleontology was among the first realms of science that American researchers could claim as their own.

The American fossil rush that followed came in two waves. In the 1870s, the field was dominated by the well-publicized but ultimately counterproductive feud between Othneil Charles Marsh of Yale and Edward Drinker Cope of the Academy of Natural Sciences. While these collectors amassed enormous collections of fossils for their respective institutions, their research remained largely out of the public eye.

1868 Hadrosaurus mount at the Academy of Natural Sciences. From http://www.naturalhistorymag.com.

The second wave came at the turn of the 20^th century, and was intrinsically related to the rise of the large museums that sprang up in America’s cities at this time. The American Museum of Natural History in New York, the Carnegie Museum of Natural History in Pittsburgh, the Field Museum of Natural History in Chicago and other, similar institutions became involved in a fierce competition to find and display the largest dinosaur (Spalding 1993). At this point, the discipline of paleontology had been marginalized in American universities, in part because of a rising interest in experiment-driven “hard” sciences like molecular biology and physics, but also because the demands of space, labor and money required by paleontological research was prohibitive.

1905 Brontosaurus mount at AMNH. From Dinosaur Tracking.

Instead, paleontologists made their homes at the large natural history museums, which were backed by wealthy benefactors who were impressed by their collections of giant fossils. At the time, it was fashionable for wealthy businesspeople to donate extravagantly to cultural institutions, including museums, in the cities where they made their fortunes. To the benefactors, there was no doubt that paleontologists and their fossil specimens could draw larger crowds than a chemist or physicist ever could. Steel tycoon Andrew Carnegie is credited with conceiving of the idea to display a mounted dinosaur skeleton as the centerpiece of his new museum in Pittsburgh. Carnegie gave CMNH $10,000 to find a giant sauropod dinosaur, preferably just like the Apatosaurus (then called “Brontosaurus”) collected by Marsh 30 years earlier. Patrons of the other large museums followed suit, and by 1905 the Carnegie Museum, the American Museum and the Field Museum all had sauropod mounts on display, along with a menagerie of other dinosaurs and prehistoric animals.

Unfortunately, by modern standards these displays favored spectacle over good science. As mentioned, vertebrate fossils almost never found as complete skeletons, but as scattered and isolated elements. As such, the museum collectors were not racing to find a single, perfect skeleton, but to amass enough individual dinosaur bones to complete a mount. The early 20^th century dinosaur mounts are typically composed of fossils found in rocks separated by hundreds of miles and millions of years in age. The collectors did not keep good records of where the fossils came from, so modern museum workers can only guess how many individual dinosaurs make up the mounts they have inherited. For example, the Stegosaurus at the Peabody Museum of Natural History is composed of at least five individuals, and researchers disagree whether the Giraffatitan at Berlin’s Museum fur Naturkunde is made up of three or five different animals.

A preparator at AMNH assembles the “Brontosaurus” mount. From http://preparation.paleo.amnh.org/5/expeditions.

Additionally, the technicians that created the mounts were attempting something that had never been done before, and perhaps inevitably, poor choices were made during the construction process. Adam Hermann, lead fossil preparatory at the American Museum of Natural History during the early 20^th century, used highly destructive techniques when creating fossil mounts. Fossils were connected to steel armatures by drilling screws and bolts directly into the bone, and broken bones and visible sections of the armature were hidden with liberal applications of plaster (Evander 2004). These practices turned out to be essentially irreversible, and modern workers are hesitant to attempt to dismantle old mounts for fear of destroying the fossils entirely.

The creation of the first fossil mounts was chiefly inspired by the vanity of museum benefactors, but their influence on audiences and their ability to draw crowds is undeniable. Although new dinosaur mounts have been constructed over the course of the 20^th century, many, if not most, of the historic mounts remain on display, important not only as evidence of prehistoric life, but as icons of the history of science and museums in America.

References

Brinkman, Paul D. (2010.) The Second Jurassic Dinosaur Rush: Museums and Paleontology in America at the Turn of the 20^th Century. Chicago, IL: University of Chicago Press.

Evander, Robert L. (2004.) “Armature Damage in a Mounted Specimen.” Presented at Society of Vertebrate Paleontology Annual Conference, Bristol, U.K.

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Tagged as dinosaurs, fossils, museums, science communication

April 3, 2012 · 1:33 am

Their hands were everywhere: the Morrison Natural History Museum

Outside the Morrison Natural History Museum. Doesn’t look like much…

Last week, I had a fantastic experience at the Morrison Natural History Museum, a little gem tucked away in the tiny town of Morrison, Colorado, on the north side of Denver. Since its opening in 1985, the Museum has served as a local educational resource covering the region’s plentiful paleontological resources. According to its website, the Museum is primarily a teaching institution. An affiliated foundation raises funds to bring local students on field trips, in support of the Museum’s mission to nurture “an understanding of and respect for the deep past.” In keeping with this teaching institution, gentle touching of all the fossils and casts is encouraged. This policy, and the design choices that go with it, are what truly set the Morrison Museum exhibits apart.

Paleontologically-inclined people are of course familiar with the Morrison Formation, the sequence of Upper Jurassic beds that extends across much of the western United States. The formation, which extends some 600,000 square miles, was named for the town of Morrison, where fossils were first discovered in 1877. The Morrison formation is probably best known as the epicenter of the “bone wars” between Othniel Charles Marsh and Edward Drinker Cope, who each led competing teams of fossil hunters across the region, attempting to best one another’s discoveries. Marsh and Cope were affiliated with the Peabody Museum in New Haven and the Academy of Natural Sciences in Philadelphia, respectively, so the fossils they collected all ended up back east. Indeed, while the Morrison region is among the most important and productive places for finding dinosaurs in the country, comparatively few of the treasures found there have remained in the region. The Morrison Natural History Museum therefore exists, at least in part, as a dedicated local repository and interpretative center for the region’s natural history.

The 1st floor Jurassic exhibit.

The Museum’s exhibit space is tiny, only 2000 square feet, but it is chock full of awesome. The exhibition consists of three main rooms, each one representing a geological time period. In the first floor Jurassic gallery, highlights include partial casts of Allosaurus and Apatosaurus, the holotype of Stegosaurus, trackways attributed to Stegosaurus and a baby sauropod, and some original 19th century lithographic prints from Marsh’s monographs. For those interested in the history of paleontology, and of science in general, those prints are particularly fascinating.

Infant sauropod trackway with model of probable trackmaker.

Cretaceous and Cenozoic exhibits are found on the second floor. Most of the objects here are casts, most notably full skeletons of Platycarpus and Pteranodon, and skulls of Triceratops, Tylosaurus and a Columbian Mammoth. There are also a number of live animals on display, including a very charismatic monitor lizard thoughtfully placed next to its close relatives, the mosasaurs.

Original 19th century lithograph prints of fossil illustrations by Marsh’s team.

The signs and labels in the exhibit are noteworthy for their succinctness and clarity. It can be extremely challenging for writers of museum copy to provide appropriate depth of content without confusing, boring or alienating audiences with too much text. Overlong and unfocused labels are particularly common in small museums, where most of the copy is written by a single curator bent on sharing everything he or she knows about a topic. On the other end of the spectrum, larger, committee-designed exhibit labels can be too brief, too simple and too narrowly focused on the exhibit’s educational goals to be of much use to anybody. Happily, the Morrison Museum avoids both of these pitfalls. Labels are simple and attractive, but still informative and up-to-date. I was rather impressed by the economical way in which they addressed the most important topics in paleontology.

An example of a brief but content-rich label.

Obviously, the fossils and other objects on display are fantastic, and many, like the trackways, are quite unique. However, as mentioned above, one of the most remarkable aspects of the Museum is that touching of all the fossils and casts is encouraged. Few objects are behind glass; everything is out in the open for people to touch and examine up close. There are many in the museum field who would be horrified by such an arrangement. When putting objects on exhibit, it is a given that they are considered consumable. No matter what precautions are taken, anything put on display will inevitably suffer damage. Of course, the flip side is that exhibit designers want to allow visitors to get as close to the objects as possible. The Morrison Museum has taken this to the extreme. The fossils, many one them irreplaceable holotype specimens, are fully exposed to accidental or intentional abuse by visitors. This is a very bold move on the part of the Museum, and it makes the point that the knowledge visitors can gain from full access to objects is more valuable that the objects themselves.

I won’t lie, my initial reaction upon seeing this exhibit layout was open-mouthed horror. But after spending some time in the space, I think the Morrison Museum may be on to something. This is a great way to tap into the multiple intelligences of visitors. Obviously, this system only works because the Museum’s attendance is on the low side (I would hate to see what the summer hordes at NMNH or AMNH would do if they were allowed to run wild among the mounts), but given these circumstances I think the open-access approach is a great educational tool.

Overall, I was very pleased with my visit to the Morrison Museum. The volunteer staff knowledgable, passionate and helpful, the exhibits were excellent, and the handful of other visitors passing through (mostly young children) seemed genuinely engaged. The Museum is well worth a stop for anyone in the Denver area, and may well be a worthwhile model for other museums to follow.

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Category Archives: reptiles

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The Life-Sized Models

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The Camptosaurus

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USNM Excavation at Dinosaur National Monument

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