Morphological Aspects of Mammalian Evolution

J. G. M. "Hans" Thewissen, Ph.D.

Professor
Department of Anatomy

Member, School of Biomedical Sciences, Kent State University

Northeastern Ohio Universities
College of Medicine
4209 St. Rt. 44, P.O. Box 95
Rootstown, Ohio 44272-0095
Phone: (330) 325-6295
Fax: (330) 325-5913
Email: thewisse@neoucom.edu
Community of Science Expertise

EXPLORE WHALE ORIGINS

Education:

1989	Ph.D.	Department of Geological Sciences (Paleontology), University of Michigan, Ann Arbor, MI.
1984	M.S.	Department of Biology, University of Utrecht, Utrecht, The Netherlands
1981	B.S.	Biology and Geology, University of Utrecht, Utrecht, The Netherlands

Professional Experience:

2006-present	Professor, Northeastern Ohio Universities College of Medicine, Rootstown, OH
1998-2006	Associate Professor, Northeastern Ohio Universities College of Medicine, Rootstown, OH
1993-1998	Assistant Professor, Northeastern Ohio Universities College of Medicine, Rootstown, OH
	Research Associate, Cleveland Museum of Natural History, Cleveland, OH
1989-1993	Postdoctoral Research Associate, Duke University Medical Center, Durham, NC

Graduate Faculty Status:

Adjunct Assistant Professor, Biological Anthropology Program, School of Biomedical Sciences, KSU

Research Interests:

My research interests center around the evolutionary patterns associated with major morphological shifts in mammalian evolution. These patterns are the best model systems for the study of evolutionary processes because they document most directly the interaction of phylogeny, functional morphology, ontogeny, and environment. To gain as full an understanding of evolutionary shifts as possible, my research program uses data from a variety of subdisciplines, including paleontology, anatomy and embryology. Overall, my research is question-driven, I use any method that can help in unraveling relevant problems, and take advantage of emerging techniques to explore questions that were previously unanswerable.

Specific morphological shifts that I have been interested in are the origin of flight in bats and its relevance to the higher phylogeny of primates and the emergence of aquatic adaptations in whales (cetaceans). The latter is a major ongoing project, focusing on the study of those cetaceans that document the land to water transition as well as the adaptations of modern cetaceans. Fossil data provide direct evidence of the evolutionary transition while the analyses of modern species offer a functional framework for interpreting the fossil data.

Of special interest are the emerging adaptations of the organ systems involved with hearing, locomotion, and osmoregulation, as these systems underwent dramatic change. The ultimate goal of this work is to provide a detailed account of the evolving adaptations in early whales, and to use this account to identify the constraints on cetacean evolution.

This project is large and growing and involves paleontological and sedimentological fieldwork in Pakistan and India, study of the embryology of cetacean ears, the functional morphology of locomotor organs, geochemistry of dental tissues, the biophysical properties of modern dolphin earbones and phylogenetic analysis. This research will be expanded by undertaking a parallel study of a group of animals that also crossed the land-water boundary in Eocene Indo-Pakistan: sirenians (manatees and dugongs).

In addition, I am also involved in a series of other projects, including the study of Eocene Pakistani micromammals (including primates), Eocene Turkish ungulates, Oligocene cetaceans from Venezuela, and patterns of bone formation in the human skull.