Richard Frederick Kay

Richard Frederick Kay

Professor of Evolutionary Anthropology

External address: 
0013 Biological Sciences Building, 130 Science Drive, Durham, NC 27708
Internal office address: 
Duke Box 90383, Durham, NC 27708-0383
(919) 684-2143


I have two areas of research:1) the evolution of primates in South America; and 2) the use of primate anatomy to reconstruct the phylogenetic history and adapations of living and extinct primates, especially Anthropoidea.

1) Evolution of primates and mammalian faunal evolution, especially in South America. For the past 30 years, I have been engaged in research in Argentina, Bolivia The Dominican Republic, Peru, and Colombia with three objectives:a) to reconstruct the evolutionary history and adaptive patterns of South America primates and other mammals; b) to establish a more precise geologic chronology for the mammalian faunas between the late Eocene and middle Miocene (between about 36 and about 15 million years ago); and c) to use anatomy and niche structure of modern mammals as a means to reconstruct the evolution of mammalian niche structure in the Neotropics.

2) Primate Anatomy. I am working to reconstruct the phylogeny of primates based (principally) on anatomical evidence; and to infer the adaptations of extinct primates based mainly on cranial and dental evidence.

Field activities
Current fieldwork is focused on the study of terrestrial biotic change in Patagonia through the 'mid-Miocene Climate Optimum' when global climate was moderate and the subtropical zone, with primates and other typically tropical vertebrates, extended their ranges up to 55 degrees of South latitude.

In this collaborative research undertaking with colleagues at University of Washington and Boise State University, the geochronology of the Santa Cruz Formation at in extreme southern Argentina is being refined using radiometric dating. Stratigraphically-controlled collections have been made of vertebrates and plant macro- and microfossils. Climate change and its impact on the biota is assessed 1) using biogeochemical analysis of stable isotopes in fossil mammalian tooth enamel; 2) by documenting changes in mammalian community structure (richness, origination and extinction rates, and ecological morphology); and 3) by documenting changes in vegetation and floral composition through the study of phytoliths. These three independent lines of evidence in a refined geochronologic framework will then be compared with similar evidence from continental sequences in the Northern Hemisphere and oceanic climatic records to improve our understanding of the timing and character of climatic change in continental high latitudes during this temporal interval.

A second field project project in its early stages is the study of the fossil vertebrates of the Amazon Basin. The latter is a collaborative effort of biologists and geologists across schools at Duke (Nicholas School) and among six North American universities. My role is to direct the vertebrate paleontology component of this project in Brazil and Amazonian Peru. The hope is to recover primates from the Oligocene through Early Miocene. New material will shed light on the phylogenetic status of African Paleogene anthropoids, one of which may be the platyrrhine sister-taxon. Also, new remains of fossil primates will help to refine hypotheses about the origins of the modern families and subfamilies of platyrrhines, all of which trace back to an Early Miocene (17-21 Ma) common ancestor. Finally, new fossil primates may further constrain the time of entry of platyrrhines into South America.

Degrees & Credentials

  • Ph.D., Yale University 1973

  • M.Phil., Yale University 1971

  • B.S., University of Michigan at Ann Arbor 1969

Fleagle, J. G., and R. F. Kay. “New interpretations of the phyletic position of Oligocene hominoids.” New Interpretations of Ape and Human Ancestry, edited by R. L. Ciochon and R. S. Corruccini, Plenum Press, 1978, pp. 181–210.

Cartmill, M., and R. F. Kay. “Craniodental morphology, tarsier affinities, and primate suborders.” Recent Advances in Primatology: Evolution, edited by D. J. Chivers and K. A. Joysey, Academic Press, 1978, pp. 205–14.

Kay, R. F., and K. M. Hiiemae. “Mastication in Galago crassicaudatus, a cinefluorographic and occlusal study.” Prosimian Biology, edited by R. D. Martin et al., Duckworth, 1974, pp. 501–30.

Hiiemae, K. M., and R. F. Kay. “Evolutionary trends in the dynamics of primate mastication.” Symp. Fourth Int. Cong. Primatology, Vol 3: Craniofacial Biology of Primates, edited by M. R. Zingeser, Karger, 1973, pp. 28–64.

Hiiemae, K. M., and R. F. Kay. Evolutionary trends in the dynamics of primate mastication. Vol. 3, 1973, pp. 28–64.


Bajpai, Sunil, et al. “The oldest Asian record of Anthropoidea.Proceedings of the National Academy of Sciences of the United States of America, vol. 105, no. 32, Aug. 2008, pp. 11093–98. Epmc, doi:10.1073/pnas.0804159105. Full Text

Kay, R. F., et al. “Two new fossil vertebrate localities in the Santa Cruz Formation (late early - early middle Miocene, Argentina), ∼51° South latitude.” Journal of South American Earth Sciences, vol. 25, no. 2, Mar. 2008, pp. 187–95. Scopus, doi:10.1016/j.jsames.2007.07.003. Full Text

Kay, Richard F., et al. “The anatomy of Dolichocebus gaimanensis, a stem platyrrhine monkey from Argentina.Journal of Human Evolution, vol. 54, no. 3, Mar. 2008, pp. 323–82. Epmc, doi:10.1016/j.jhevol.2007.09.002. Full Text

Goin, F. J., et al. “A new generalized paucituberculatan marsupial from the oligocene of Bolivia and the origin of 'shrew-like' opossums.” Palaeontology, vol. 50, no. 5, Sept. 2007, pp. 1267–76. Scopus, doi:10.1111/j.1475-4983.2007.00706.x. Full Text

Vizcaíno, S. F., et al. “Vertebrados de los niveles inferiores de la Formación Santa Cruz (Mioceno inferior-medio, Argentina).” Ameghiniana, vol. Resumenes, XXIII Jornadas Argentinas de Paleontología Vertebrados, Trelew, Argentina, 21-23 de mayo., 2007.

Coleman, M., and R. F. Kay. “Evaluaing hearing sensitivity in Homunculus patagonicus.” American Journal of Physical Anthropology, vol. 98, 2007.

Bajpai, S., et al. “An overview of terrestrial mammals from Cambay shale, Vastan lignite mine, Gujarat (western India), with new taxa and age constraints.” Journal of Vertebrate Paleontology, vol. 27, Suppl to Issue 3, 2007, pp. 42A-43A.

Forasiepi, A. M., et al. “A new species of Hathliacynidae (Metatheria, Sparassodonta) from the middle Miocene of Quebrada Honda, Bolivia.” Journal of Vertebrate Paleontology, vol. 26, no. 3, Sept. 2006, pp. 670–84. Scopus, doi:10.1671/0272-4634(2006)26[670:ANSOHM]2.0.CO;2. Full Text


Kay, R. F., and D. D. Johnson. “New platyrrhines from the middle Miocene of Argentina.” American Journal of Physical Anthropology, vol. Suppl. 22, 1996, pp. 136–37.

Kay, R. F., and B. A. Williams. “Recent finds of monkeys from the Oligocene/Miocene of Salla, Bolivia.” American Journal of Physical Anthropology, vol. Suppl. 20, 1995.

Meldrum, D. J., et al. “Phylogenetic relationships of Cebus and Saimiri inferred from mitochondrial DNA sequences and dental anatomy.” American Journal of Physical Anthropology, vol. Suppl. 16, 1993, pp. 144–45.

Madden, R. H., and R. F. Kay. “Aportes al conocimiento de la fauna de mamiferos del Grupo Honda, Mioceno, Colombia.” Ix Jornadas Argeninas De Paleontologia De Vertebrados, Trelew, Chubut, 1992.

Kay, R. F., and M. R. L. Anthony. “Dietary evolution in platyrrhine primates and the comparative method.” Journal of Vertebrate Paleontology, vol. 11, 1991.

Ford, S. M., et al. “New platyrrhine astragalus from the Miocene of Colombia.” American Journal of Physical Anthropology, vol. Supplement 12, 1991, pp. 73–74.

KAY, R. F. “A POSSIBLE GIANT TAMARIN FROM THE MIOCENE OF COLOMBIA.” American Journal of Physical Anthropology, vol. 81, no. 2, WILEY-LISS, 1990, pp. 248–248.

MADDEN, R. H., and R. F. KAY. “NEW STIRTONIA-VICTORIAE MATERIAL FROM THE MIOCENE OF COLOMBIA.” International Journal of Primatology, vol. 8, no. 5, PLENUM PUBL CORP, 1987, pp. 473–473.