Oklahoma State University Center for Health Sciences
Oklahoma State University Center for Health Sciences

Anatomy and Vertebrate Paleontology

O'BrienHaley O'Brien, Ph.D.
Assistant Professor of Anatomy

Education | Professional Experience | Professional Societies
| Publications | Outreach and Press | Awards



Dr. O’Brien’s main research focus is on paleophysiology, or how unique thermoregulatory capabilities have influenced the evolution of large mammals across Cenozoic climate change. She uses a phenomenon called “selective brain cooling,” which is common to many large, Laurasiatherian mammals, as a model system for generating inferences regarding the interface between an organism’s physiology and its environment over geological time. Her primary data collection involves radiopaque latex injection of ungulate cranial vasculature and CT-scan examination. The osteological correlates established through these methods can then be sought in fossil skulls to directly infer evolution of this physiology from the fossil record.


Instructional Activities

  • Nervous Systems – MSII and Graduate
  • Biomedical Foundations – MSI and Graduate
  • Vertebrate Paleontology – Graduate



Ph.D. Biomedical Sciences – Anatomical Sciences Track
Ohio University
Ohio Center for Ecology and Evolutionary Studies
Athens, OH

B.S. Marine Biology
College of Charleston
Charleston, SC


Professional Experience

Assistant Professor, Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK

Research Associate in Mammalogy, Department of Zoology, American Museum of Natural History, New York, NY

Affiliated Research Associate in Mammalogy, Sam Noble Museum of Natural History, Norman, OK

Research Associate, Department of Vertebrate Paleontology, National Museum of Kenya, Nairobi, Kenya

Instructor of Mammalogy, Department of Biology, Ohio University, Athens, OH


Professional Societies

American Society of Mammalogists
Society for the Preservation of Natural History Collections
Lambda Alpha, the Anthropology Honors Society
Society of Vertebrate Paleontology
The Paleontological Society
Sigma Xi, the Scientific Research Society
Geological Society of America
Society for Integrative and Comparative Biology


Exemplar Publications

Integrative and Comparative BiologyGignac, P. M. and H. D. O’Brien. 2016. “Suchian feeding success at the interface of ontogeny and macroevolution.” Integrative and Comparative Biology, 56: 449­–458. [doi: 10.1093/icb/icw041]

O’Brien, H. D., P. M. Gignac, T. Hieronymus, and L. M. Witmer. 2016. “Post-natal growth of the cranial arteries of the giraffe (Artiodactyla: Giraffa camelopardalis).”PeerJ, 4:e1696. [doi: 10.7717/peerj.1696]

O'Brien, H.D., Faith, J.T., Jenkins, K.E., Peppe, D.J., Plummer, T.W., Jacobs, Z.L., Li, B., Joannes-Boyau, R., Price, G., Feng, Y-X., & Tryon, C.A. 2016. Unexpected convergent evolution of nasal domes between Pleistocene bovids and Cretaceous hadrosaur dinosaurs. Current Biologyhttp://dx.doi.org/10.1016/j.cub.2015.12.050

O'Brien, H.D. 2015. Cranial arterial pattern of the Sri Lankan spotted chevrotain, Moschiola memmina, and comparative basicranial osteology of the Tragulidae. PeerJ 3:e1451. PDF DOI: 10.7717/peerj.1451.

O'Brien, H.D. & Bourke, J. 2015. Physical and computational fluid dynamics models for the hemodynamics of the artiodactyl carotid rete. Journal of Theoretical Biology 386: 122-131. PDF.

O'Brien, H.D. & Williams, S.H. 2014. Using Biplanar Fluoroscopy to Guide Radiopaque Vascular Injections: A New Method for Vascular Imaging. PLoS ONE  9(5):e97940.

Outreach and Press

Anatomical Models

"Vascular safety net" doesn't protect the brains of giraffes from dangerous pressure changes," an Anatomy To You blog post, co-authored with Jason Bourke.

Nature Research Highlights: "Mammal with a dinosaur nose"

Christian Science Monitor​: "Weird convergence: Extinct wildebeest cousin and dinosaur shared noses"

National Geographic"Ice Age beast honked like a dinosaur"

CBC Radio Program Quirks and Quarks: "Ancient wildebeest cousin with dinosaur horn"



2016                Society of Vertebrate Paleontology’s Alfred Sherwood Romer Prize

2013                Mid-American Paleontology Society Outstanding Research Award

2011                Distinguished Osteopathic Commitment Award, Ohio University Heritage College of Osteopathic Medicine

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