Uhen Lab Research
I have broad interests centered on the diversification of mammals and their expansion into new adaptive zones, particularly focused on Cetacea and other marine mammals. The origin and diversification of cetaceans and aquatic adaptations that develop in the evolution of cetaceans are of great interest to me. My doctoral dissertation and monograph include a reassessment of the taxonomy of Dorudon atrox, an archaeocete whale from Egypt, a description of its anatomy, and analyses of functional morphology. I have continued my work on archaeocetes by searching museums and prospecting for fossils throughout the southeast US and the world. This work has produced many new fossil whale specimens, including several new species, genera, and a new family as well.
Dorudon atrox by Mary Parrish.
New Taxa Named by Uhen: Notnamaia, Natchitochia, Natchitochia jonesi, Pelagiceti, Ancalecetus, Ancalecetus simonsi,
Basilotritus wardii (originally Eocetus wardii), Chrysocetus, Chrysocetus healyorum, Cynthiacetus,
Cynthiacetus maxwelli, Ocucajea, Ocucajea picklingi, Supayacetus, Supayacetus muizoni, Xenorophidae,
Albertocetus, Albertocetus meffordorum
Basilotritus wardii (originally Eocetus wardii), Chrysocetus, Chrysocetus healyorum, Cynthiacetus,
Cynthiacetus maxwelli, Ocucajea, Ocucajea picklingi, Supayacetus, Supayacetus muizoni, Xenorophidae,
Albertocetus, Albertocetus meffordorum
Peruvian Eocene archaeocetes and penguins by Karl Buell.
I also study the origin of modern cetaceans (Neoceti) to characterize the origin of Mysticeti and Odontoceti from archaeocete ancestors. I am studying specimens from the Pacific Northwest, Alaska, and North and South Carolina to better characterize the transition from archaeocetes to Neoceti. This work involves the documentation of the dramatic changes in cranial architecture involved in the shift in feeding modes from individual prey capture and oral processing in archaeocetes, to prey capture using echolocation in odontocetes, and filter feeding in masticates.
Evolution of fully aquatic whales by Mary Parrish.
As Chair of the Executive Committee and a member of the Paleobiology Database (PBDB), I have compiled occurrence data for all marine mammal and marine bird fossils worldwide, covering their entire temporal and geographic distribution. One goal for this project is to be able to see how cetacean diversity changes in response to global climate change, and in particular, what effect changes in oceanic circulation have on the origin of modern whales. The initial phase of this work on cetaceans has been completed, so now I and fellow researchers are planning to compare changes in all secondarily aquatic tetrapods to changes in mollusk faunas and geochemical indicators of past sea surface temperatures and other paleoclimatic indicators.
All cetacean fossil localities on the planet created with the Paleobiology Database Navigator.
I have an ongoing field project in the Pisco Basin of Peru, which includes sediments from the middle Eocene to the Pliocene. The Eocene deposits have produced both protocetid (middle Eocene) and basilosaurid (late Eocene) archaeocetes. I am currently working on specimens curated at the Museo de Historia Natural, University Nacional Mayor de San Marcos (Lima), and am planning to develop this project further, along with colleagues from Europe and Peru. I am currently exploring the use of unmanned aerial vehicles (UAVs) to assist in finding additional fossil specimens in the field. This technology has advanced dramatically in recent years, and will undoubtedly prove to be transformational in field paleontology.
Mark D. Uhen (foreground) and Daniel Ksepka (background) in the field in the Pisco Basin in Peru.
I am also working on several collaborative projects with many others including an exploration of the evolution of body size in marine mammals over the Cenozoic with the Integrating Macroecologial Pattern and Processes across Scales NSF Research Coordination Network. Also, a project with Mark Clementz on documenting life history events using stable isotopes of carbon and oxygen in the deciduous and adult teeth of basilosaurid archaeocetes from the US and Egypt.
Dental eruption sequence in Dorudon atrox.
My students are pursuing projects in foraminifera of the Cretaceous of Tanzania, cranial morphometrics of odontocetes, biogeography of marine mammals over the Cenozoic, and macroecological changes of terrestrial mammal faunas over the Cenozoic in response to climate change. The prep lab is also busy preparing early odontocetes and masticates from the Pacific Northwest on loan from the Emlong Collection at the Department of Paleobiology at the USNM.