Part of a series of articles titled Park Paleontology News—Vol. 18, No. 2, Fall 2026.
Article
Discovering the First Fossil Insects in Badlands National Park
The White River Badlands, which include Badlands National Park in South Dakota, played a central role in the early development of paleontology in the American West. Just a few years after British paleontologist Sir Richard Owen coined the term “Dinosaur” in 1842, Hiram Prout described the first fossils from the Badlands (Prout 1846). Joseph Leidy described more Badlands fossils in 1847 through the 1850s (Leidy 1847, 1848, 1853). The infamous Bone Wars rivalry between Leidy’s protégé, Edward Drinker Cope, and Othniel Charles Marsh, begun in 1868, included numerous White River fossils. Consequently, many natural history museums have White River Badlands fossils on display or in their collections.
The Badlands is best known for fossil mammals of the middle Cenozoic (Age of Mammals), including marsupials, insectivores, rodents, carnivores, and herbivores. It also contains a decent record of fish, amphibians, reptiles, and birds. Invertebrates, particularly snails, are common, but a few atypical deposits have produced clams and ostracods (Evans and Welzenbach 1998; Benton et al. 2015). Insect traces have been found throughout some of the Badlands’ units in the form of dung beetle balls and larval casings (Benton et al. 2015). However, insect body fossils were never found.
In 1971, Dr. Phil Bjork from the South Dakota School of Mines and Technology conducted expeditions to collect from a layer of sediment known as the Leptauchenia beds. Bjork and his associates found nearly everything that could be found in the Badlands in this zone. This collection had the potential to be the most significant of his career, but he retired before publishing about anything from that collection.
Fast forward to 2010. I had just graduated from the school of mines and was working with a private consulting company doing monitoring and mitigation. The school had just opened its new paleontology collections and lab facility, the Paleontology Research Laboratory. The original collections area was in the old gymnasium and had to be moved into the new facility. This was a massive undertaking by everyone working in the Museum of Geology and the paleontology department.
For my consulting work, I would be on a job site for several weeks straight, then off for a few weeks. This allowed me time to volunteer with the Museum of Geology and help with the collections move. Two undergraduates helped me unpack and organize the collection made by Bjork’s 1971 field work. As we were going through the insect trace material, I noticed a vial labeled “Carabidae,” which I did not recognize. We were coming across “Scarabidae” for every dung beetle ball, so the novelty of a different, unrecognizable name caught my attention.
Looking into the vial, I noticed a small, round, oval-shaped object that didn’t look too different from a fossil seed. Fossilized Hackberry tree (Celtis) seeds were common, including in the Leptauchenia beds. Having pretty good nearsighted vision, I noticed that one side had striated grooves going along the length of the object, and the other side was smooth with four bumps. It hit me that I was looking at the fossilized remains of a tiny beetle abdomen. The striations were the ornamentation of the wing casings, and the bumps on the other side were attachment sites for the abdominal legs.
I was familiar enough with White River fossils to know that fossilized insects had never been found anywhere in the White River Group sediments (South Dakota, Nebraska, Colorado, Wyoming, North Dakota, and Montana). The only site that came close was Florissant Fossil Beds National Monument, which is the same age as the Chadron Formation (latest Eocene). But the depositional environment of the two sites was dramatically different.
The Florissant Formation preserved soft-body material: insects, leaves, feathers, and even fur. On the other hand, the Chadron and Brule formations of the White River Group only yielded hard parts: bones, teeth, and shell. Insect exoskeletons are made of chitin reinforced by sclerotin, a protein that helps with rigidity. This is very different from bone, so I knew that the presence of an insect body fossil in the White River was significant.
NPS / Ed Welsh
I studied the specimen and did an X-ray fluorescence analysis under a scanning electron microscope, which was graciously provided by Ed Duke at the South Dakota School of Mines and Technology. It became clear that no original material was preserved, and the insect body itself was composed of high amounts of calcium (Ca), carbon (C), and an even higher amount of oxygen (O). Together, they make calcium carbonate (CaCO3). The entire body was replaced by this mineral. I held on to this information but nearly forgot about it because I had to work, pay rent, and figure out life after grad school.
I began working at Badlands National Park in 2012, doing monitoring and mitigation work, finding new fossils and sites associated with construction projects. My first substantial site from that year would become my first publication from working in the park (Boyd and Welsh 2014). I would find other things to publish later in regard to Badlands fossils.
These included the oldest occurrence of the rare dog Osbornodon renjiei (Welsh 2014), a description and restudy of the only known American nimravid cub (Welsh et al. 2015), and the new latest occurrence of amynodonts (hippo-like rhinos) from North America (Welsh et al. 2018). My specialty was White River vertebrates, particularly carnivores and ungulates. Through it all, the knowledge that a fossil insect existed from this park was always in the back of my mind, and I kept an eye out for another one.
Skip ahead to 2023, and I was on a casual outing with some park seasonal staff and volunteers. We were prospecting at an improvised location to help them experience what it is like to find fossils in the park. One of the seasonal staff members found some bones on a small mound of outcrop. I was looking closely at small fragments when I saw Hackberry seeds, or so I thought. I picked one up to show the others what a fossil seed looks like.
Then I noticed something was off. The “seed” was oval-shaped and had striations running along its length. I realized I had finally found the second-ever fossil beetle from the Leptauchenia beds. I would like to say my reaction was calm, collected, and mature. It was actually quite the opposite, involving some repetitive deity acknowledgments coupled with excited pacing and arm-waving.
Courtesy A. Neubaum
In 2026, I teamed up with an entomologist and beetle specialist, Matt Brust, from my undergraduate alma mater, Chadron State College. We finally described and got the word out that fossil insects can be found in the White River Group. It is not often that someone gets to add an entire class of animal to a study area that has been so heavily collected and explored for nearly two centuries: 180 years between 1846 and this article.
We were only able to identify the beetles at the familial level, belonging to the Carabidae, a family of common ground beetles. The beetles we described are well documented in other insect sites like the Florissant Formation. They provide no groundbreaking news for the natural history of the family. However, their presence is one of the more significant discoveries in the history of Badlands paleontology.
NPS / Ed Welsh
Fossil insects are rare, but they are not unheard of. Normally, sites that produce them experienced exceptional conditions that created sedimentary deposits called Lagerstätte. Out of 433 official NPS sites, more than 280 (65%) are known to have fossils. Only a few have fossil insects. The two best sites by far are Lagerstätte: Fossil Butte National Monument in Wyoming and Florissant Fossil Beds National Monument in Colorado.
Badlands does not fit the criteria of a Lagerstätte, so it is perplexing to discover creatures that usually indicate such a site. Further exploration into the circumstances of such fossil insect preservation is now apparently needed. I am more than thrilled to add Badlands National Park to this exclusive list of NPS insect sites. I hope the announcement of this discovery will inspire future paleoentomologists to discover (or vertebrate paleontologists to notice) more and add to the expansive lexicon of Badlands fossils.
An article by Ed Welsh and Matthew Brust will be released this fall in the 2026 Proceedings of the South Dakota Academy of Science.
References
Benton, R. C., D. O. Terry, E. Evanoff, and H. G. McDonald. 2015. The White River Badlands: geology and paleontology. Indiana University Press, Bloomington, Indiana.
Boyd, C. A., and E. Welsh. 2014. Description of an earliest Orellan Fauna from Badlands National Park, Interior, South Dakota and implications for the stratigraphic position of the Bloom Basin Limestone Bed. Dakoterra 6: 124–147.
Evans, J. E., and L. C. Welzenbach. 1998. Episodes of carbonate deposition in a siliciclastic-dominated fluvial sequence, Eocene-Oligocene White River Group, South Dakota and Nebraska. Geological Society of America Special Paper 325: 93–115.
Leidy, J. 1847. On a new genus and species of fossil Ruminantia, Poebrotherium wilsoni. Proceedings of the Academy of Natural Sciences of Philadelphia 3: 322–326.
Leidy, J. 1848. On a new fossil genus and species of ruminatoid Pachydermata, Merycoidodon culbertsonii. Proceedings of the Academy of Natural Sciences of Philadelphia 4: 47–50.
Leidy, J. 1853. Remarks on a collection of fossil Mammalia from Nebraska. Proceedings of the Academy of Natural Sciences of Philadelphia 6: 392–394.
Prout, H. A. 1846. Gigantic Palaeotherium. American Journal of Science 2: 88–89.
Welsh, E. 2014. The first record of Osbornodon (Carnivora: Canidae) from the Orellan of South Dakota. Proceedings of the South Dakota Academy of Science 93: 43-53.
Welsh, E., C. A Boyd, K. Spearing, and P. Z. Barrett. 2015. Stratigraphic and taxonomic revision of a North American false saber-toothed cat cub. Proceedings of the South Dakota Academy of Science 94: 141–153.
Welsh, E., D. C. Pagnac, and C. A. Boyd. 2018. New material of Amyndontidae (Perissodactyla) from Badlands National Park and its implications on the Whitneyan-Arikareean transition. Proceedings of the South Dakota Academy of Science 97: 175–191.
Last updated: October 28, 2026