Carnegie Museum of Natural History

One of the Four Carnegie Museums of Pittsburgh

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.

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The Giant Eurypterid Trackway: A Great Fossil Discovery on Display in the Carnegie Museum of Natural History

Figure 1.

When museum patrons enter Carnegie Museum of Natural History’s Benedum Hall of Geology, they encounter a one-ton block of coarse sandstone with a series of bilateral footprints encased on the rock’s surface. Most visitors don’t know what type of creature made these footprints (Fig. 1) or realize that this fossil trackway represents one of the great fossil discoveries in the history of western Pennsylvania paleontology.

Figure 2. Illustration by Kay Hughes.

Last month, the cover of Pennsylvania Geology (Fig. 2) helped address both deficiencies. The magazine bears a colorful illustration by Kay Hughes of a 315 million-year-old scene: a large six-legged arthropod emerging from the water and dragging its tail onto a sand bar among fallen Lepidodendron logs. The intruder is a Giant Eurypterid, a creature known to science as Palmichnium kosinskiorum, and a member of an extinct family of arthropods informally called “sea scorpions” that are distant biological cousins.

Within the journal is a fuller explanation for the artistic interpretation of the creature behind the Benedum Hall trackway, an article I co-wrote with Kay Hughes and John Harper titled, Reflections on Palmichnium kosinskiorum-The Footprints of Pennsylvania’s Elusive Elk County Monster.

Fortuitous Discovery

Figure 3. Photograph of Elk County in situ trackway looking southward (Brezinski and Kollar 2016).

Figure 4. Trackway closeup showing tail drag on display in Benedum Hall of Geology (Brezinski and Kollar 2016)

Seventy-two years ago, in an Elk County section of the Allegheny National Forest, James Kosinski, a preparator in the Education Department of Carnegie Museum of Natural History, and his brother Michael were hunting deer in heavily wooded terrain. When Michael stumbled upon a large sandstone boulder bearing a pattern of unusual impressions, he informed James, who (Fig. 3) immediately recognized the impressions as the fossil tracks of an unknown animal (Fig. 4).

Later, when James described the discovery to Carnegie Museum’s Dr. E. Rudy Eller, Curator of the Section of Invertebrate Paleontology, and Dr. J. Leroy Kay, Curator of Vertebrate Paleontology, plans were made to remove a section of the boulder containing the best-preserved section of the trackway and transport the heavy block to the museum.

Exhibit History

Figure 5. Former Paleozoic Hall Silurian Period Marine Diorama with Eurypterids.

Upon arrival at the museum in 1948, the sandstone block was prepared for exhibition and placed near the museum’s Coal Forest exhibit in 1949. In 1965, the trackway was incorporated as a floor centerpiece in the newly open Paleozoic Hall which featured dioramas of characteristic life forms of that Era’s time periods (Cambrian, Ordovician, Silurian, Devonian, Pennsylvanian, and Permian) along with representative fossils from the museum collection. (Fig. 5) In 1998, when Paleozoic Hall was dismantled, the trackway was placed temporarily in the Invertebrate Paleontology lab. The trackway returned to public view in 2007 as part of Bizarre Beasts, a temporary exhibition in the R. P. Simmons Family Gallery about unusual life forms. When Bizarre Beasts closed, I worked with James Senior, Chair of the museum’s Exhibit Department, to place the trackway in the Benedum Hall of Geology entrance as an introduction to great fossil discoveries from western Pennsylvania.

The Research – Locality Data Supports Recent Theory

The fossil trackway was initially identified by Dr. Kay as a hopping reptile inhabiting a Pennsylvanian coal forest 300 million years ago. Although Dr. Eller, citing his own research, suggested the track was formed by a crawling eurypterid, it would take 35 more years for the fossil trackway to be studied by expert arthropod paleontologists from Europe.

The eventual designation of Palmichnium kosinskiorum as a holotype specimen (CM 34388), a category of first order scientific importance, dates to the fossil’s description as a eurypterid trackway in a 1983 research paper by Dr. Derek E. G., Briggs and Dr. W. D. J. Rolfe, titled, A giant arthropod trackway from the Lower Mississippian of Pennsylvania (Journal of Paleontology, 57, 377 – 390). In paleontology, when a non-scientist such as Michael Kosinski discovers a fossil of importance, paleontologists, in this case Derek Briggs and Ian Rolfe, name the new fossil species after the founder, hence P. kosinskiorum.

For years, paleontologists in the Section of Invertebrate Paleontology assumed the scientific conclusions of Briggs and Rolfe (1983) about the eurypterid trackway were beyond dispute. This situation changed in 2009, when Yale University Professor Adolph Seilacher, a world-renowned expert on fossil trackways visited the museum. While Briggs and Rolfe concluded the trackway formed in a marine sandstone, Seilacher explained to me that the trackway was likely formed in an eolian or wind-blown sand environment. He also recommended that someone investigate the rocks at the fossil location in Elk County to substantiate his hypothesis.

Figure 6. D.K. Brezinski at trackway. 

Later that year, when I accompanied David K. Brezinski, Associate Curator Adjunct, Section of Invertebrate Paleontology, to re-locate and re-examine the sandstone boulder with the remaining tracks, we discovered the original geologic and deposition conclusion by Briggs and Rolfe (1983) was incorrect (Fig. 6). In 2011, we reported these new findings at the Northeastern Sectional Meeting of the Geological Society of America in Pittsburgh.  After the meeting, we continued our research and eventually published our conclusion that the geologic age of the trackway was Early Pennsylvanian age and the embedded footprints represented a fluvial sand bar environment of deposition.(Reevaluation of the Age and Provenance of the Giant Palmichnium Kosinskiorum Eurypterid Trackway, from Elk County, Pennsylvania, Brezinski and Kollar (2016),  Annals of Carnegie Museum 84, 39 – 45,)

School Groups and Museum Interpreters

Based upon repeated anecdotal reports from the Interpreters who guide tour groups through the museum’s exhibit halls, the eurypterid trackway is one of the most celebrated education stops for elementary school students. According to Interpreter Patty Dineen, the appealing factors of the trackway include the size and possible scariness of the creature who made the tracks, the fact the track-maker lived long before the dinosaurs, the fossil’s local origin, and the sheer amount for information that can be gathered from the ancient preserved tracks.

Figure 7. Interpreter field trip.

As part of an effort to better inform school groups about the eurypterid trackway, in 2017 Patty Dineen and Joann Wilson, co-coordinators and instructors for the museum’s Natural History Interpreters, arranged for six Interpreters to participate in a PAlS geology fall field trip to the fossil site in Elk County. (Fig. 7) An important by-product of field excursion was the creation of an instructional video that explains how museum scientists conduct research.

“Treasures of the Carnegie” Planning for a better Trackway Experience

Now that an illustration exists (Fig. 1) of the eurypterid that shaped the trackway walking out of the 315 million-year-old Olean River onto a sand bar, it might be time to consider how to best devise an improved visual and virtual tour experience for the Carnegie patrons and school groups.

Albert D. Kollar is Collections Manager for the Section of Invertebrate Paleontology at Carnegie Museum of Natural History. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Mesozoic Monthly: Sophogramma

Welcome to April! Have you seen any flowers blooming yet? Often, when we think of flowers, we also think of their pollinating buddies, the bees. However, bees are not the only pollinating insects around today, and the same was true during the Mesozoic Era (the ‘Age of Dinosaurs’). One interesting prehistoric pollinator is Sophogramma lii, a beautiful pollen-eating lacewing from the Cretaceous, the third and final time period of the Mesozoic.

Sketch of Sophogramma lii alongside the Jurassic/Cretaceous seed plant Cycadeoidea by ginjaraptor on DeviantArt. Cycadeoidea was not a flowering plant, even though it looks like one; the flower-like structures are known as strobili and are actually types of cones!

Modern lacewings, for those who aren’t familiar, are a group of small flying insects with two pairs of wings of about equal size. They get their common name from the net-like pattern of veins on their wings. Most of today’s lacewings are predators that eat other small insects. Sophogramma, however, belongs to an extinct group of relatively large lacewings called the Kalligrammatidae, which were not predators but rather pollen eaters and juice drinkers. This group is commonly called the “butterflies of the Jurassic” due to several similarities with modern butterflies: their mouthparts formed long, tube-like siphons for drinking plant juices; their feeding habits resulted in the transference of pollen between plants; and their wings had scales and were distinctly patterned to ward off predators. Astoundingly, we know that kalligrammatids had patterned wings because these patterns are actually preserved in their fossils! Sophogramma lii had whimsical winding stripes along the edges of all four wings. Although we don’t know the exact color of the wings, we do know that these stripes were lighter in color than the rest of the wing. Other kalligrammatids had large eyespots adorning their wings, like many butterflies today.

Beautifully preserved fossil of Sophogramma lii clearly showing the light-colored wavy stripes along the edges of its wings. Image from a research paper by Yang et al. (2014).

The plants that Sophogramma snacked on (and incidentally, pollinated) almost certainly lacked flowers. Flowering plants, technically called angiosperms, didn’t evolve until early in the Cretaceous, roughly 130 million years ago, but kalligrammatids had been around since at least the middle part of the preceding Jurassic Period, about 160 million years ago. So what plants were kalligrammatids eating for all that time? And why did these insects die out just as angiosperms were becoming common? Well, kalligrammatids’ host plants probably consisted of spore-bearing vascular plants such as ferns and non-flowering seed plants including conifers, cycads, ginkgos, and a variety of extinct forms. Before angiosperms burst onto the scene, these types of plants dominated land ecosystems. Despite lacking flowers, these plants would still have used spores and pollen to reproduce, providing kalligrammatids with plenty of food. Once angiosperms evolved their flowers, these plants rapidly diversified and presumably outcompeted the host plants that kalligrammatids such as Sophogramma would have relied upon.

With a wingspan of six inches (15.3 cm), Sophogramma lii was a relatively large insect. Its fossils have been found in the Yixian Formation, an Early Cretaceous-aged rock unit that crops out in northeastern China. The Yixian represents a forested environment that many dinosaurs, archaic birds, pterosaurs, and other hungry critters called home. The distinctive stripes of Sophogramma likely helped it survive attacks by drawing these predators’ attention to its relatively ‘expendable’ wingtips instead of vital parts such as the head or body. I wouldn’t personally be inclined to eat one of these ancient lacewings, but with so many of those polarizing Peeps® on the shelves at this time of year, I think some people might actually prefer a seasonal Sophogramma snack!

Lindsay Kastroll is a volunteer and paleontology student working in the Section of Vertebrate Paleontology at Carnegie Museum of Natural History. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Wind and Migration

Spring is just around the corner, even if it doesn’t feel like it the last few days.  In the Laurel Highlands, the trout lilies and trillium are blooming, the closed umbrella forms of May apples are poking through the leaf litter, and the migrating birds are on their way.  Some are already here.  For many birders, spring is the most exciting time of year.  We’ve waited months to see something different, all dressed up fancy and bright after growing new feathers over the winter.  We also get a chance to see some birds as they lay over, northward bound to the boreal forest or arctic tundra.   So, when will they be here?  That depends on two things: time and wind.

Birds want to arrive as soon as there’s food to eat so they can stake their claim on a nice plot of land to raise a family.  Since the tundra is still frozen, birds that breed there, like the Grey-cheeked Thrush, won’t be coming until around the second week of May.  Louisiana Waterthrushes on the other hand, arrived the beginning of April, as soon as insects were flying along the mountain streams they call home.  Both species know when to depart their wintering grounds based on daylength, honed over thousands of years through natural selection.

Gray-cheeked Thrush

Louisiana Waterthrush

The other thing birds base their decision to leave upon is weather, specifically wind.  And it effects how many migrants might be arriving on a particular day at a particular place.  Put another way, birds’ instincts effect the range of dates they arrive, weather influences the specific dates.

How is wind important? Hawks soar using thermals (warm air rising from heated land masses) or ridges (wind pushed up by ridges). Songbirds on the other hand, migrate at night and fly when the winds are light or are in the direction they are heading (when they literally have a tail wind). Because low pressure systems spin counter-clockwise fall migrants will move after a low front passes in the fall or before a low front arrives in the spring. We like to use Hint.fm wind maps to help predict when and where migrants can move. Besides being informative, these maps show the beautiful complexity of wind patterns.

You might now be wondering how we use these maps. Let’s use Sept 19th, 2012 as an example. At 1pm EST there are light, southerly winds along the eastern seaboard and throughout the Southeast. There are also strong southerly winds in the western part of the Midwest. If you imagine that these patterns will slowly move eastward (say half an inch by sunset) you might predict strong migration for the eastern seaboard, the southeast, and the Midwest.

If you made such a prediction you would be right, but you don’t have to take our word for it. It turns out that birds taking off and migrating at night are picked up on radar. Here’s a radar loop from 5pm EST Sept 19th to 1:40am EST Sept 20th. At the very beginning you can see storm systems across Wisconsin and Iowa. As the frames progress you can see intense circular “clouds” appearing across the east, Southeast, and Midwest. These “clouds” are millions of birds taking off after sunset and continuing to migrate throughout the night. They’re circular because they are centered around each radar. We call these appearances “blooms” because they blossom around the radar sites.

Notice that where the storm system is and several hundred miles to the east (about an inch) there aren’t any blooms. That’s because this is the area which is experiencing strong northerly winds. Rather than fighting the headwind, birds in this area are staying put until more favorable winds come through. The winds along the gulf appear to be favorable for a trans-gulf crossing and you can see the clouds of birds take off and begin to move off the gulf coast shoreline (especially Texas). Looking at the longer loop from 3pm EST the 19th to 2pm EST the 20th you can also see birds taking off in Illinois and Iowa after the front has passed through.

What about the spring you ask?  Remember, since the low-pressure systems spin counter clockwise birds migrate ahead of a front.  A few days ago, the night of April 11th, there were southerly winds resulting in good movement northward across the southeastern U.S.  Looking ahead, the next significant warm-up with nightly, light, southerly winds won’t occur until next week, mid-week (around Tuesday April 21st). If piecing together wind patterns and radar isn’t your thing, Cornell Lab of Ornithology has you covered.  They’ve put together something they call BirdCast which puts combines weather, radar, and bird data (ebird) to forecast bird migration for the U.S.

Ruby-crowned Kinglet

We may be quarantined but that doesn’t mean we have to miss the magic of migration.  As I write, there’s a ruby-crowned kinglet singing in a maple across the street.  We can bird, or learn birds, in our backyard or neighborhood.  We can bird a new local patch and contribute what we see to science by logging our sightings into ebird.com.  Over the last few years people in Pennsylvania have found some amazing birds in their own backyard.  A Black-backed Oriole from Mexico, a Painted Bunting which overshot the Carolinas by more than a few states, and even a Bahama Woodstar.  With migration, we never know exactly what we’re going to get.  To me that’s part of the magic.  That, and knowing that it’s time for them to come, carried hundreds or even thousands of miles by their wings and the wind.

Luke DeGroote is the avian research coordinator at Powdermill Nature Reserve, Carnegie Museum of Natural History’s environmental research center. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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A Rare New Species for Natural History: Earth System Scientists

Part of Anthropocene science is earth system science, the study of anthropogenic change of whole earth systems–the water systems, geological systems, ecosystems, and atmosphere–and their feedbacks with each other and human society. Historically earth system scientists have been a rare species at natural history museums, because they do not collect organismal specimens or valuable rocks. Instead they collect samples of air, water, microorganisms, and soil. But CMNH recognizes these scientists are key to understanding the Anthropocene and translating it to the public.

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Two earth scientists have recently joined CMNH. Dr. Carla Rosenfeld will be the museum’s first curator of Earth Sciences. Rosenfeld’s work focuses on the microbial ecology of earth systems: how they naturally mediate the vast majority of water and soil chemistry and can be used to remediate pollution. For example, she is testing the potential for fungi to remove toxins from acid mine drainage. 

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Dr. Bonnie McGill is a science communication fellow with the Climate and Rural Systems Project (CRSP) in the Anthropocene Science Section. With CRSP she is working with rural communities to explore local climate change impacts, identify the social and ecological systems involved, and design community-level actions. Much of her previous work was in the Midwest studying how soil and water conservation in corn and soybean production impacted greenhouse gas emissions and nitrate pollution of rivers.

Bonnie McGill is a Science Communication Fellow at the Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences working at the museum.

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“Say Cheese!” – Specimen Imaging in Invertebrate Zoology

“A picture tells 1,000 words.”

Specimen imaging is a method of documenting specimens in the Invertebrate Zoology collection for research as well as collection maintenance. Digitizing the collection allows it to be more accessible to the scientific community. Specimen-based documentation includes capturing the data from the specimen as well as images of the specimen from different angles. Images of labels serve as a primary data capture that may then be used to populate a database of specimen records.

Most of the imaging currently being done is based on requests from the entomology community needing images of specimens known to be deposited at the Carnegie. There are many historical specimens that are not otherwise imaged but are referenced in older publications. These specimens include cataloged species vouchers referred to as types, or specimens referenced in publications that are of interest to researchers studying those species.  

Specimen photography is also essential when discovering new species. When a paper is published describing a new species, images of the designated types are included. The type series includes the series of specimens that were examined and used to describe the new species in detail. These images should be taken with a scale line to show the size of the specimen. Images of prepared dissections are also included.

Imaging techniques include using a copy stand, flash lighting, and focus-stacking through software that produces a final high-quality image with all parts of the specimen in focus. A light box may also be used, as an alternative to flash lighting, to provide even lighting and sharp images.  

A macro ring flash helps with producing even lighting when imaging live insects that are moving or are very small and need to be really close to the lens.  

Photographing live specimens that will lose their color when preserved in alcohol, such as caterpillars, is crucial.  Larval images are a major component of the caterpillar collection and are incredibly valuable documentation of larval growth.  Raising caterpillars is a way to document the life history of different species of moths and butterflies, and their associated caterpillars.  Since the caterpillars will be stored in alcohol, the color will be lost in the preserved specimen, but these characteristics will be recorded through high-quality images.  

Several other types of equipment are used to capture images at higher magnification so that characters may be seen in greater detail.  Taking an image through a compound microscope allows one to capture an image that may be used to draw a detailed illustration. An image taken through a Scanning Electron Microscope offers even greater detail. All-together, the image collection is a major component of the archived data that contributes to the understanding of the specimens in the collection. This includes digital files and images on older slide film that still need to be scanned. The digital image collection continues to grow daily, and serves the broader entomological community that needs access to the reference specimens stored in the Invertebrate Zoology collection at the Carnegie.

Vanessa Verdecia is a collection assistant in the museum’s Invertebrate Zoology Section. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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What is the Anthropocene and How Does it Relate to Earth Day?

The Anthropocene translates roughly to “human” “times” and it is the proposed current geological period that started when the activities of human beings collectively began to have big impacts on Earth system processes, so much so that it leaves a record in Earth’s geology. While it is hard to untangle when exactly the Anthropocene should start, the leading proposal is around 1950, when human population and technology really started to grow rapidly.

The first Earth Day was organized about 2 decades after the Anthropocene “officially” started. Back then the public was already seeing how much impact humans were having on the planet and they were concerned. In the 1970s, America responded and passed all of our major environmental laws, the Clean Water Act, the Clean Air Act, the Endangered Species Act. Today, 50 years later, we know a lot more about how human activities are changing the planet, including the threat of global climate change. And like those folks celebrating the first Earth Day, we again have the great opportunity to respond and protect what we love.

Stewardship in the Anthropocene

One big question with the Anthropocene is what the heck are we going to do about it? How can we respond? The concept of stewardship is helpful here. Stewardship can be defined in different ways, but generally it refers to the job of ‘caring for the land and species.’   At CMNH a number of our scientists use their research to inform how people can live and care for the land to produce things they want while taking care of nature. We want to find these beneficial land-use and stewardship practices and share them more broadly. If more people can find ways to support the human economy while also protecting the health of ecosystems, the Anthropocene may cease to be a problem.

Examples of Stewardship Research

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Ancient Canyon Live Oak, Santa Cruz Mountains

Curator of Anthropocene Studies, Dr. Nicole Heller conducts field work in California, where she works to adapt conservation frameworks to better include people and their positive stewardship practices in conservation decision-making. She is working with a group of scientists, farmers, foresters, conservationists, and Indigenous tribes to map and monitor all the different stewardship practices on the landscapes and understand how those practices work together to affect ecological and social health.

Curator of Amphibians and Reptiles, Dr. Jennifer Sheridan, conducts field work in Borneo, where she works with a consortium of scientists and a large palm oil producer to assess how spatial arrangement of forest and plantation can maximize biodiversity conservation. Because deforestation for oil palm plantation is the largest driver of deforestation in this biodiversity hotspot, such partnerships are critical to effective conservation.

Curator of Birds, Chase Mendenhall is a leader in establishing methods for monitoring changes in biodiversity and quantifying factors that enhance re-diversification of human-disturbed landscapes. This work has largely been conducted in Costa Rica.

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Matt Webb and Jon Rice installing decorative bird safe window film. 

Since 1961, Powdermill Avian Research Center (PARC) staff have operated one of the North America’s best bird banding programs, recording the timing of bird migration and a broad variety of life history and ecological attributes of migrating birds. PARC uses their data on birds to inform a wide variety of stewardship actions across the landscape to help birds survive. In one project, PARC works jointly with the American Bird Conservancy and select industrial partners to develop window glass that birds can see and avoid collisions.

Nicole Heller is Curator of Anthropocene Studies at the Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences working at the museum.