• Two

    John Day Fossil Beds

    National Monument Oregon

Meet the Paleontologists


Paleontologist and Museum Curator, Josh Samuels, recording field notes.

NPS photo

Joshua X. Samuels

Museum Curator/ Paleontologist


2001 B.Sc., Biology - College of Idaho

2007: Ph.D., Biology - University of California, Los Angeles

2007: Dissertation: Paleoecology and Functional Morphology of Beavers (Family Castoridae)

2007: Ph.D. Advisor: Dr. Blaire Van Valkenburgh

Research Interests: My primary research interests lie in the broad fields of vertebrate paleontology and evolution. My dissertation research was designed to aid in reconstruction of past ecosystems and in understanding of the evolution of rodents. Rodents are the most species rich group of mammals, live in nearly every terrestrial habitat on earth, and display diverse locomotor and dietary adaptations. Relative to larger mammals, rodents tend to have more localized populations, shorter dispersal distances, and shorter generation times. Consequently, rodents are likely to adapt more rapidly to changing conditions, making them very informative as to the timing and magnitude of environmental changes over the Cenozoic. Nevertheless, rodents have been largely overlooked in paleoecological reconstructions due to a lack of data on their ecomorphology.

Much of my research to date has focused on using morphometric techniques to infer the locomotor and dietary ecology of extinct rodents. Living rodents show a diverse array of locomotor types, including: swimming, climbing, digging, jumping, and gliding forms. Though most rodents are omnivores or generalist herbivores, some species have independently evolved highly specialized carnivorous, insectivorous, and herbivorous diets. Examination of skeletal and dental differences between rodents with different habits has revealed how their anatomy relates to functional characteristics. My results can be used by other researchers to easily infer the locomotor and dietary habits of extinct rodents, and to study their evolution over time.

I am currently working on several collaborative projects in the areas of evolution and paleoecology. These include: 1) the evolution of burrowing and semi-aquatic mammals, 2) the evolution of mammalian body size, and 3) the differing responses of large and small mammals to past and future climate change. I am also working on a revision of the lagomorphs (rabbits and pikas) and description of several new species from the John Day Formation.

Disciplinary Expertise: Vertebrate paleontology, evolutionary biology, functional morphology, and paleoecology.

Recent Publications:
Meachen, J.A., and J.X. Samuels. In Press. Evolution in coyotes (Canis latrans) in response to the megafaunal extinctions. Proceedings of the National Academy of Sciences.

Samuels, J.X., and J. Zancanella. 2011. An early Hemphillian occurrence of Castor (Castoridae) from the Rattlesnake Formation of Oregon. Journal of Paleontology, 85(5): 930-935.

Van Valkenburgh, B., A. Curtis, J.X. Samuels, D. Bird, B. Fulkerson, J. Meachen-Samuels, G.J. Slater. 2011. Aquatic adaptations in the nose of carnivorans: evidence from the turbinates. Journal of Anatomy, 218: 298-310.

Rybczynski, N., E.M. Ross, J.X. Samuels, and W. Korth. 2010. Re-Evaluation of Sinocastor (Rodentia: Castoridae) with Implications on the Origin of Modern Beavers. PLoS ONE 5(11): e13990. doi:10.1371/journal.pone.0013990

Samuels, J.X. 2009. Cranial morphology and dietary habits of rodents. Zoological Journal of the Linnaean Society, 156(4): 864-888.

Samuels, J.X., J.A. Meachen-Samuels, and P.A. Gensler. 2009. The first mid-Blancan occurrence of Agriotherium (Ursidae) in North America: a record from Hagerman Fossil Beds National Monument, Idaho. Journal of Paleontology, 83(4): 597-603.

Samuels, J.X. and B. Van Valkenburgh. 2009. Craniodental adaptations for digging in extinct burrowing beavers. Journal of Vertebrate Paleontology, 29(1): 254-268.

Samuels, J.X. and B. Van Valkenburgh. 2008. Skeletal indicators of locomotor adaptations in living and extinct rodents. Journal of Morphology, 269: 1387-1411.

Jennifer Cavin

Jennifer L. Cavin
Museum Technician/Fossil Preparator

NPS Photo

Jennifer L. Cavin
Museum Technician/Fossil Preparator

2000. BS in Biology with a minor in Geology from Chadron State College, Nebraska
2004. MS in Paleontology from South Dakota School of Mines and Technology

Master's Thesis: A Pleistocene paleofauna from the Sand Hills of Nebraska, Graves/Potter localities, Cherry County

Jennifer has been preparing fossil specimens since she was an undergraduate in 1997. She remembers her first day in a paleontology lab, "I walked in the door. They handed me a tool and an oreodont skull. I was hooked from that moment on!" Jennifer continued to work as a fossil preparator throughout graduate school. She spent her winters preparing fossils in the School of Mines laboratory, and she spent her summers at Badlands National Park doing field work, mostly at the Big Pig Dig Quarry. After graduation, Jennifer worked at Augustana College in Illinois and for the Utah Geological Survey in Salt Lake City, Utah preparing and doing field work with dinosaurs. Jennifer's first love in paleontology, however, was ancient mammals. So it is not surprising that she jumped at the chance to work with mammals once again. After a brief time at the University of Nebraska, Lincoln, she accepted a job at John Day Fossil Beds NM. Jennifer spends her time preparing, molding and casting the fossil specimens found within the fossil beds. She is also part of the field collecting team. Jennifer really enjoys all aspects of her job and says she has found her permanent home here in eastern Oregon.

Did You Know?

Image of fossilized alder leaves

The fossil leaves found at the Painted Hills represent an assemblage of broad-leaf deciduous trees that were growing on the edge of lakes and streams.