James Hopson, PhD

Professor
Department of Organismal Biology and Anatomy
Committee on Evolutionary Biology
Research Associate Field Museum of Natural History

 

Office: Anatomy 34
Department of Organismal Biology and Anatomy
University of Chicago
1027 E. 57th St.
Chicago, IL 60637

Tel. (773) 702-8099
Fax. (773) 702-0037
Email:

 

 

 

 

 

 

 

Research Interests

Vertebrate paleontology, particularly the evolutionary history of the Synapsida - the "mammal-like reptiles" and mammals; morphology and systematic of non-mammalian synapsids (especially therapids) and Mesozoic mammals; functional morphology of the feeding apparatus, especially of the dentition, in the transition from primitive amniotes to mammals; macroevolutionary patterns in the synapsid fossil record; amniote phylogeny; tetrapod faunas of the Permian and Mesozoic.

My research centers on the evolutionary history of the Synapsida, major branch vertebrates that includes fossil and living mammals and the now extinct "mammal-like reptiles". The nearly continuous fossil record of late Paleozoic and Mesozoic synapsids, spanning more than 100 million years, provides the best available evidence of the gradual evolution of a major new grade biological organization. I am interested in tracing the structural changes that have taken place in the transition from basal amniotes of the late Paleozoic to the essentially modern mammals of the late Mesozoic. My studies include both morphological descriptions and functional interpretations of fossil synapids, as well as phylogenetic analyses using cladistic methods and computer-based parismony algorithms. A pervasive factor in synapids evolution, which has created problems in working out a generally agreed-upon phylogeny, has been the independent, i.e., convergent, origin of similar complex morphologies in different lineages. Major goals of this research are:

(1) to develop a well-corroborated phylogeny of synapsids;

(2) to work out patterns of morphological change, including the "progressive" changes in the direction of mammals; and

(3) to utilize these patterns of change to test competing theories of large-scale evolution.

I am interested in supervising research on fossil vertebrates, particularly, though not exclusively, on "mammal-like reptiles" and (primary Mesozoic) mammals. This research may include descriptive and functional morphology and phylogenetic analysis.

 

Selected Publications

Hopson, J.A. and H.R. Barghusen (1986). An analysis of therapsid relationships. In: The Ecology and Biology of Mammal-like reptiles (eds. by N. Hotton III, P.D. MacLean, J.J. Roth, & E.C. Roth) pp. 83-106. Washington, DC: Smithsonian Institution Press.

Hopson, J.A. (1991). Systematic of the non-mammalian Synapsida and implications for patterns of evolution in synapsids. In: Origins of higher groups of tetrapods: controversy and consensus, (eds. by H.P. Schultze & L. Trueb), pp. 635-693. Ithaca: Cornell University Press.

Allen, E.F. and J. A. Hopson (1991). Evolution of the auditory system in Synapsida ("mammal-like reptiles and primitive mammals) as seen in the fossil record. In: The Evolutionary Biology of Hearing (eds. By D.B. Webster, R.R. Fay and A.N. Popper) pp 587-614. New York: Springer-Verlag.

Hopson, J.A. (1995). Patterns of evolution in the manus and peers of non-mammalian therapsids. Journals of Vertebrate Paleontology. Vol. 15 pp. 615-639.

 

 

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