Blogs from our Scientific Researchers

Carnegie Museum of Natural History is home to active research and vast scientific collections. Our scientific researchers regularly contribute to the blog at the museum.

June 25, 2020 by wpengine

Behind the Scenes with the Baron de Bayet and L. W. Stilwell Collection Part 3: The Wild West Formed Million of Years Ago

photo of Badlands National Park — Figure 1: Badlands National Park today, National Park Service photo, 2014. This view of the Badlands topography illustrates the erosion that took place over the last 2 million years.

The Lakota called the Badlands “Mako Sica” or “land bad.” The early French-Canadian trappers referred to it as “les mauvais terres pour traverse” or “bad lands to travel through.” Seventy-five million years ago, this area was a lush underwater seaway filled with creatures such as mosasaurs, plesiosaurs, diving birds, fish, baculites, and ammonites (Figure 2).

Figure 2: Taxa that swam in the Western Interior Seaway from *Dinosaurs in Their Time* exhibit at Carnegie Museum of Natural History. Photo by Patty Dineen.

The Stilwell fossils of Cretaceous age (Figure 3) were deposited in a black mud that accumulated on the sea floor from 82 to 70 million years ago (Figure 4). The Pierre Shale is part of the extensive Western Interior Seaway of North America (Figure 5). Museum visitors can view a changing geographic representation of the seaway on a wall-mounted flat screen monitor within the Dinosaurs in Their Time exhibit. The seaway extended from the Gulf of Mexico, Florida, and southern Gulf Coast, north through Texas, Kansas, Colorado, Wyoming, Montana, the Dakotas, and the Canadian Provinces of Alberta and Saskatchewan. This vast waterway terminated in the Artic region of Canada. At the time of the Pierre Sea, the ice sheet-free greenhouse to hothouse paleoclimate was much warmer than it is today, creating the highest sea levels in earth’s history. Sea level rises and falls were primarily controlled by the presence or melting of glaciers in the polar regions, the shifting of the continents, and the uplifting of proto-Rocky Mountains by plate tectonics.

Figure 3: Western Interior Seaway fossils on display at Carnegie Museum’s *Dinosaurs in Their Time* exhibit. Stilwell fossils are highlighted in blue.

Figure 4: Outcrop photo of Pierre shale.

Figure 5: Western Interior Seaway approximately 75 million years ago. Red dot locates Deadwood, South Dakota today.

Fast forward to the Wild West of the 1890’s, and dealers such as Stilwell found and sold fossils to museums and private collectors. Knowledge of Badlands fossils spread as far as Europe, and by 1889 Bayet wanted some for his own collection.

Next, in our final post of this series, we will delve into the Stilwell-Bayet correspondence in search of clues about how fossils were bought and sold over a century ago.

Joann Wilson is an Interpreter for the Department of Education and a volunteer with the Section of Invertebrate Paleontology. Albert Kollar is Collections Manager for the Section of Invertebrate Paleontology. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

The Bromacker Project Part VI: Seymouria sanjuanensis, the Tambach Lovers

New to this series? Read The Bromacker Fossil Project Part I, Part II, Part III, Part IV, and Part V.

Seymouria sanjuanensis fossils — Two exquisitely preserved, nearly complete adult skeletons of *Seymouria sanjuanensis* that were discovered in the Bromacker quarry in 1997. Photo by Dave Berman.

At lunchtime on the last day of the 1997 field season, Thomas Martens discovered the two exquiste specimens shown above, the only fossils found that year. Thomas had uncovered a piece of the hip region with some attached vertebrae that resembled, once again, those of the ancient amphibian Seymouria. Because our work time was limited, we estimated the length of the specimen and rushed to extract it from the quarry. When we flipped the block over, a few pieces of rock fell out, revealing a series of vertebrae of a second individual in the block. We were thrilled to learn that Thomas had discovered two specimens of Seymouria. We put the rock pieces back in place and quickly finished plastering the block. There was just enough time for Dave, Stuart Sumida, and I to return to our hotel, clean up, quickly pack, and meet Thomas, his family, and his fossil preparator Georg Sommer for a celebratory dinner. What a great way to end the field season.

Working in tight quarters to quickly extract the *Seymouria* specimens discovered at lunchtime on the last day of the field season. Clockwise from right: Georg Sommer, Dave Berman, and the author. Photo by Stuart Sumida, 1997.

Seymouria had already been known from the Bromacker quarry. Thomas had discovered and identified two skulls in 1985, fossils he brought with him when he came to Carnegie Museum of Natural History (CMNH) in 1993 to study for six months with Dave Berman under a CMNH-financed fellowship. Both skulls were of juvenile individuals. Of the two known species of Seymouria, Dave and Thomas were excited to discover that the Bromacker skulls were nearly identical to those of Seymouria sanjuanensis. The 1997 lunchtime discovery of the two complete adult specimens confirmed the identification of the Bromacker Seymouria as S. sanjuanensis.

The first discovered species of Seymouria was Seymouria baylorensis, from near Seymour, Baylor County, Texas, from which its name was derived. Seymouria sanjuanensis was first found in San Juan County, Utah, by Dave Berman and the field team he was leading as a graduate student at the University of California, Los Angeles. Dave’s advisor, Dr. Peter Vaughn, named it Seymouria sanjuanensis in reference to the county of discovery. Another discovery of five specimens of this species preserved together was made by Dave in New Mexico in 1982.

Comparison of the skulls of *Seymouria baylorensis* (top) and *S. sanjuanensis* (bottom). The individual bones of the skull are color coded. Skulls scaled to same size. Image from Wikimedia Commons.

Seymouria baylorensis is geologically younger than S. sanjuanensis and has a more robust skull, larger and fewer teeth of variable size, and a subrectangular postorbital bone compared to the chevron-shaped postorbital of S. sanjuanensis.

Seymouria is considered a terrestrial amphibian that only returned to water to breed. Its strongly built skeleton provided the support needed to move on land. With its numerous, slender, pointed teeth, S. sanjuanensis most likely ate insects and small land-living vertebrates. We know that the Bromacker Seymouria didn’t consume fish, because not a single fish fossil, scrap of fish fossil, or fish coprolite (fossil poop) has ever been found at the Bromacker quarry. Study of the rock deposits preserving the fossils at the Bromacker indicate a lack of permanent water, which would explain the absence of fish.

Growth series of skulls of *Seymouria sanjuanensis* from the Bromacker Quarry showing (left to right) early juvenile, late juvenile, and adult growth stages. Photos by the author, 2006.

Conditions for breeding must have been favorable in the Tambach Basin, the ancient basin where sediments preserving the Bromacker fossils accumulated, because several juvenile specimens of Seymouria are known. The smallest is a skull measuring about ¾ of an inch long. In a study led by our colleague Josef Klembara (Comenius University, Slovak Republic), we determined that the smallest individual was post-metamorphic—in other words, no longer a tadpole—based on the presence of certain ossified bones in the skull. In tadpoles, these skull elements are cartilaginous; that is, they haven’t yet turned to bone.

The discovery in Germany of the same species of Seymouria previously known only from New Mexico and Utah has important implications in terms of paleobiogeography (the study of the distribution of species in space and time). At the time S. sanjuanensis was alive, the continents were merged to form the supercontinent Pangaea. The presence of S. sanjuanensis across Pangaea, north of a roughly east-west trending mountain range, indicates that climatic or physical barriers (e.g., deserts, inland seas, mountain ranges) didn’t prevent its dispersal.

Map showing the arrangements of the continents in the Early Permian. The locality where *Seymouria* occurs in present-day New Mexico, Texas, and Utah and the Bromacker locality in present-day Germany are indicated. Map modified from Scotese, 1987.

The two Seymouria specimens preserved together were a big hit in the local region in Germany. Museum der Natur (MNG) exhibit preparator Peter Mildner nicknamed them the “Tambacher Liebespaar” (“Tambach Lovers”) after a painting entitled “Gothaer Liebespaar” (“Gotha Lovers”) on exhibit in the Herzogliches Museum of the Stiftung Schloss Friedenstein (also the parent organization of MNG). This name caught on and is fondly used by our German friends and colleagues. Peter even made a fleshed-out model of the two Seymouria specimens in their death pose. The proprietor of the hotel in which we stayed hung a copy of the model of the Tambach Lovers and a framed collage of newspaper articles featuring the Bromacker on a wall in one of the hotel rooms, which she named the “Präparation Suite” (i.e. “Preparation Suite” in reference to the preparation of fossils). I often stayed in this room.

The painting entitled “Gothaer Liebespaar” (“Gotha Lovers”), which is on display at Herzogliches Museum of the Stiftung Schloss Friedenstein, Gotha, Germany. Image from Wikimedia Commons and provided by Thomas Martens.

Tambach Lovers postcard — Postcard showing the Tambach Lovers. The postcard was made for and sold by the Museum der Natur, Gotha. Photo of the postcard by the author, 2020.

Stuart Sumida (left) and Heike Scheffel, proprietor of the Hotel Wanderslaben where we stayed (right), with the model of the Tambach Lovers in the “Präparation Suite.” The framed collage to the right of the model holds newspaper articles featuring the Bromacker project. Photo by the author, 2003.

A cast of the Tambach Lovers specimen and a model of Seymouria sanjuanensis are exhibited in the Fossil Frontiers display case in CMNH’s Dinosaurs in Their Time exhibition. Be sure to look for them once the museum re-opens. And stay tuned for my next post, which will feature the unusual bipedal reptile Eudibamus cursoris.

For those of you who would like to learn more about Seymouria sanjuanensis, here is a link to the publication describing the 1997 specimens: https://www.tandfonline.com/doi/abs/10.1671/0272-4634(2000)020%5B0253%3AROSSSF%5D2.0.CO%3B2.

Amy Henrici is Collection Manager in the Section of Vertebrate Paleontology at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Keep Reading

The Bromacker Fossil Project Part VII: Eudibamus cursoris, the Original Two-legged Runner

June 22, 2020 by wpengine

The Zebra Mussel and the Shopping Cart

Zebra mussels (Dreissena polymorpha) are eastern European freshwater bivalves that invaded North America. Something unusual about their biology facilitated this invasion.

In marine waters, many benthic (living on the bottom) animals add their babies to the plankton, the mix of small and microscopic organisms largely adrift in the water column.

The situation is different in freshwater where almost all benthic animals lay their eggs on the bottom. (Freshwater plankton exist, but the organisms that compromise it spend their whole lives as plankton.) I don’t know why marine and freshwater animals differ that way, but they do. Zebra mussels are a major exception to this rule; they live in freshwater, but they put their babies (larvae) in the plankton.

How did zebra mussels invade North America? Partially loaded ships require ballast to safely navigate at sea. Decades ago, ships were loaded with rocks and dirt (and slug eggs) as ballast, and when they reached their intended port these materials were removed and replaced with cargo. That is why so many invasive slugs (essentially all your garden slugs are non-native) arrived first in seaports and spread from there. Ballast tanks that can be easily filled with water and drained are a design feature of modern ships, and depending upon some ship’s departure points, their ballast water sometimes contains larval zebra mussels. For many years, ships were slow enough that zebra mussel larvae arrived in North America dead, but eventually reductions in ocean crossing time worked in the invaders’ favor. In 1988 some larval zebra mussels arrived alive in the ballast water pumped out into Lake St. Clair near Detroit. By 1990, zebra mussels had infested all the Great Lakes and now they occur in more than half of the 50 United States.

Fig. 1. Freshwater snail (*Elimia livescens*) colonized by zebra mussels (left) and uncolonized (right). From Douglas Lake, Michigan 30 Aug. 2015 (photo by T.A. Pearce).

The economic and ecological devastation caused by zebra mussels is legendary. Zebra mussels make threads (byssal threads) for attaching to hard objects. They clog intake pipes of city water supplies and power station cooling pipes, requiring costly removal. They compete with native mussels and young fish for food and can smother or hinder movements of our native mussels, snails (Fig. 1), and crayfish when they settle in large numbers.

Fig. 2. Replica of shopping cart covered in zebra mussels.

A noteworthy item that became encrusted with zebra mussels is a shopping cart that was dredged out of Lake Superior in 2012. A replica of the shopping cart was on display during the We Are Nature exhibit at Carnegie Museum in 2018 (Fig. 2).

Lest you think I am biased against zebra mussels, I will note two possibly positive things you can say about them. First, they filter water efficiently and because they pump up to a liter (quart) per day, they cleaned up the formerly polluted water in Lake Erie. But even that can be negative, because they removed so much plankton from the water that our native species now have a hard time finding enough to eat. Second, because zebra mussels selectively concentrate certain toxic metals, including uranium, they have potential to be used in bioremediation efforts to clean water of this radioactive pollutant (Immel et al. 2016). But those are the only good things you can say about them. Mostly, they wreak havoc.

Literature Cited

Immel, F., Broussard, C., Catherinet, B., Plasseraud, L., Alcaraz, G., Bundeleva, I. & Marin, F. 2016. The shell of the invasive bivalve species Dreissena polymorpha: biochemical, elemental and textural investigations. PloS One, 11(5): e0154264. https://doi.org/10.1371/journal.pone.0154264

Timothy A. Pearce, PhD, is the head of the mollusks section at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Behind the Scenes with the Baron de Bayet and L. W. Stilwell Collection, Part 2: The Wild West a Century Ago

black and white photo of Deadwood from a distance — Figure 1: Deadwood, Dakota Territories 1879. Image courtesy of the Deadwood Historic Preservation Commission, City of Deadwood Archives.

black and white photo of a Deadwood street — Figure 2: Deadwood, Dakota Territories 1879. Image Courtesy of Deadwood Historic Preservation Commission, City of Deadwood Archives.

Fancy yourself on the hottest day in summer in the hottest spot of such a place without water — without an animal and scarce an insect astir — without a single flower to speak pleasant things to you and you will have some idea of the utter loneliness of the Bad Lands.” Thaddeus Culbertson, 1850

When Lucien Stilwell stepped off the stagecoach on September 25, 1879, he was not your typical visitor to Deadwood. Photos of Stilwell in later years show a thin scholarly figure with glasses. In 1879, Deadwood, Dakota Territories was known for gold prospecting, gambling and lawlessness. Just three years prior, Wild Bill Hickock had been shot in the back while playing poker here. It would be a few more years until Seth Bullock, first sheriff of Deadwood, would begin to bring order to town.

As Stilwell stepped off the stagecoach, he was leaving a fifteen-year career in the grocery and grain business in Cairo, Illinois. A yellow fever epidemic blanketing parts of the United Sates prompted him to uproot his life. He arrived just one day before a fire destroyed over 300 buildings and displaced over 2000 people in Deadwood. According to Michael Runge, City Archivist of Deadwood South Dakota, photos of Deadwood in 1879 (Figures 1 and 2), were taken just before the great fire. If you look closely at Figure 2, you can see a law office, hardware store, liquor store, and city market.

Despite the great fire and the dangers of Deadwood, Lucien W. Stilwell found a job at a bank, brought his family to town and built a home. Along the way, he became fascinated by the fossils in the surrounding Black Hills. He began a careful study of the region and developed relationships with other fossil collectors. Eventually, he turned his hobby into a side business.

Figures 3 & 4: CM 33067 – Baculites collected by Stilwell. Baculites, translated as “walking stick rock”, are an extinct group of straight cephalopods that swam the seas 75 to 80 million years. “Sutures” or growth lines are formed when the animal adds new shell material as it grows. Sutures assist paleontologists in the identification of the genus and species.

Prior to leaving the bank in 1890, Stilwell began selling Badland fossils and minerals. In a correspondence to the Baron de Bayet of Brussels dated January 12, 1889, Stilwell said, “I tried to catch your meaning in your last letter. As I understand it, you wanted one of every specie and variety of fossils I had, excepting the large and costly specimens of mammals.”

In one letter to Bayet, Stilwell wrote, “I put in a number of baculites, all of which have some different interest. One is to show fine sutures another to show iridescence to rare degree, another to show size, another to show form so differing as to be a specie of baculite by another name…” Albert Kollar of the Section of Invertebrate Paleontology explained that in circumstances when the exact stratigraphic locality is questionable, having the original fossil labels as seen in Fig. 4 are critical to accurate fossil identification. Stillwell was a capable researcher because of his grasp of the geology and paleontology of the Badlands region. Figures 3 and 4 show a baculites sold by Stilwell to Bayet. There are 100 Stilwell fossils in the 130,000 specimen Bayet collection.

The next post in this series will explore why dealers such as Lucien W. Stilwell, found so many fossils in the Badlands.

Many thanks to the generous assistance of Michael Runge, Archivist for the City of Deadwood, South Dakota.

Meet our two new curators!

Dr. Travis Olds

photo of new curator of minerals Travis Olds

Hello! My name is Travis Olds. I’m Assistant Curator of Minerals in the Section of Minerals and Earth Sciences at Carnegie Museum of Natural History. I’m from the Upper Peninsula of Michigan, the northern part of the state that is sometimes confused as being a part of Canada, but also considered by many as one of the most beautiful places on Earth. People born in the U.P., as we call it, are known colloquially as “Yoopers,” and like Canadians we are some of the kindest people you will meet. Many Yoopers have an accent that is best described as a mix between Canadian and Minnesotan; we tend to elongate and over-emphasize vowels in spoken words, with favorites being “ya, eh, you betcha, and don’tchya know.” Our favorite dish is the pasty (“pastee”), a baked meat and vegetable-filled pastry that was introduced early in our state’s history by Cornish miners who traveled to the area to make a living and share their knowledge of mining techniques developed overseas.

Hundreds of mines have operated in the U.P. over the last ~200 years, yielding billions of tons of iron and manganese used for the steel produced here in Pittsburgh, and millions of tons of copper used across the world for plumbing, electrical lines, and electronics. Although many mines in the U.P. have long been abandoned, a few iron and copper mines are still in operation today. For several generations my family has made a living working in the mines, including my father and uncle, who were large influencers to my interest in minerals.

As I started collecting and learning more about minerals I became fascinated by radioactive minerals, the ones containing uranium and thorium. Uranium minerals come in many beautiful shapes and colors. They sometimes fluoresce neon green and yellow colors under UV light, and emit invisible high-energy particles during their decay. Although we owe our basic understanding of X-rays and many modern medical technologies and treatments to early studies of radioactive minerals, uranium remains one of the most controversial elements on the periodic table. It has been used to create exceptionally valuable technology but has also created unimaginable evil and pain. In the future, I believe nuclear power will likely become one of the dominant methods for producing “base-load” power to replace the antiquated and highly pollutive coal and natural-gas burning energy plants. I study the atomic arrangement and properties of uranium minerals because they are good analogs for advancing several aspects of nuclear power generation, from mining to processing and storage of used fuel and waste. My mineral collecting trips have taken me to unique places underground in Colorado, Utah, and the Czech Republic, and thanks to the group of friends and researchers that I work with, I have been lucky to find and describe 20 new minerals. At the museum, I research minerals to improve technology and better understand how humans are changing the minerals found on the Earth’s surface.

Photos of our new minerals can be found on my Mindat.org page.

Dr. Carla Rosenfeld

photo of new curator of earth sciences Carla Rosenfeld

Hello! I’m Carla Rosenfeld, the new Assistant Curator of Earth Sciences in the Section of Minerals and Earth Sciences at Carnegie Museum of Natural History. I received my Ph.D. in Soil Science and Biogeochemistry from Penn State and a B.S in Chemistry from McGill University. Following my Ph.D., I worked as a postdoctoral fellow at the Smithsonian National Museum of Natural History and University of Minnesota. After several years away, I am so excited to be returning to Pennsylvania to continue my research!

As a researcher, I am an interdisciplinary environmental biogeochemist. I use tools from mineralogy, geochemistry, and microbiology to study how pollutants and nutrients behave in the environment. I am fascinated by how biology, geology, and chemistry interact – for example when plant roots scavenge nutrients from soils by dissolving minerals, or when organisms form biominerals (think teeth, shells, and corals). Understanding how living and non-living things interact in different environments helps us to understand and predict how nature will respond to changing climate and other human impacts. Because I’m interested in how microbes make and alter minerals in soils, I’ve visited all sorts of places to collect soils, plants, water, and microbes (mostly bacteria and fungi). I’ve been down to the bottom of the deepest and oldest underground iron mine in Minnesota (Sudan Mine, ~ 1 mile below the ground surface!), to hot springs and the world’s only captive geyser in Idaho, and, right here in Southwest PA, to acid mine drainage remediation systems! Outside of science, I love to spend time outdoors biking (I even biked across the US from CT to CA one summer), mushroom hunting (my favorite mushrooms to find are golden chanterelles, Cantharellus cibarius or Cantharellus lateritius), and generally spending time outdoors. I also love to bake (including science cakes!), and I’ve kept a spreadsheet detailing everything I’ve baked for the last 5 years!

The Mineralogy of Ice Cream

by Travis Olds

Have you ever made ice cream at home?

You may have noticed that homemade ice cream has a different texture than what you buy at the grocery store or get at an ice cream shop. Homemade ice cream can taste “grainy” with a coarse texture, unlike the creamy Ben and Jerry’s from the store. This is because ice crystals in homemade ice cream are usually much larger than the ice cream made by professionals.

close up of ice crystals — “Ice Crystals”by glenngurley is licensed under CC BY-NC-SA 2.0

This is where mineralogy comes in. In nature, large mineral crystals take time to grow, sometimes growing for up to 100,000 years or more! The same is true for ice and snow, which happen to be minerals too. The shape and size of snow crystals that fall from the sky are controlled intricately by the outside air temperature, relative humidity, and time. Snowflakes are usually largest when they spend a long time in the air and at temperatures a bit below the freezing point, near 15 °F. At colder temperatures, the crystals grow quickly and are smaller. Fortunately, we won’t be seeing snow for a while, however, summer can bring even larger balls of ice from the sky! During thunderstorms, hail stones can grow VERY large (up to 15 cm or nearly 6 inches in diameter), sometimes spending up to 30 minutes swirling around updrafts in the icy and rainy conditions within storm clouds.

two-inch piece of hail next to ruler in the grass

To make a smooth and creamy ice cream, companies like Ben and Jerry’s use freezers cooled to very cold temperatures, -40 °F, that quickly freezes the cream thereby producing tiny ice crystals. Ice cream prepared at home is made with a salty mixture of ice and water that can reach nearly -5 °F, but at this temperature the ice crystals grow more slowly and larger. When the crystal size reaches about 50 micrometers, roughly the width of a human hair, your mouth senses the coarse texture.

Three steps you can take to make creamier ice cream at home:

1. Use a higher fat content by adding more cream. More fat will “spread” out water molecules in the cream, creating more nucleation sites, or growth places, for ice and smaller crystals.

2. Using crushed ice, instead of ice cubes, will bring the ice/salt mixture to a lower temperature. Also, pre-chilling the cream and sugar before placing it in the salt bath will help speed up freezing, producing smaller crystals.

3. Use “dry ice,” or frozen carbon dioxide, available at many grocery stores, for even lower temperatures and faster crystallization. But be careful, dry ice should only be used with proper gloves and under adult supervision.

Travis Olds is Assistant Curator of Minerals at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences working at the museum.

Behind the Scenes with the Baron de Bayet and L. W. Stilwell Collection Part 3: The Wild West Formed Million of Years Ago

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The Bromacker Project Part VI: Seymouria sanjuanensis, the Tambach Lovers

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The Zebra Mussel and the Shopping Cart

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Behind the Scenes with the Baron de Bayet and L. W. Stilwell Collection, Part 2: The Wild West a Century Ago

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Meet our two new curators!

Dr. Travis Olds

Dr. Carla Rosenfeld

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The Mineralogy of Ice Cream

by Travis Olds

Three steps you can take to make creamier ice cream at home:

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