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. “Anthropoid origins: past, present, and future.Anthropoid Origins: The Fossil Evidence, edited by J. G. Fleagle and R. F. Kay, Plenum Press, 1994, pp. 675–98.

Rasmussen, D. T., and R. F. Kay. “A Miocene Anhinga from Colombia, and comments on the zoogeographic relationships of South America's Tertiary avifanua.” Avian Paleontology, edited by K. E. Campell, Special Publication, Nat. Hist. Mus. of Los Angeles County, Los Angeles, 1992, pp. 225–30.

Kay, R. F., and B. A. Williams. Dental evidence for anthropoid origins. Vol. Suppl. 14, 1992.

Kay, R. F., and F. E. Grine. “Tooth Morphology, wear, and diet in Austrolopithecus and Paranthropus.Evolutionary History of the “Robust” Austrolopithecines, edited by F. E. Grine, Aldine de Gruyter, 1989, pp. 427–47.

Kay, R. F. “Fayum.” Encyclopedia of Human Evolution and Prehistory, edited by I. Tattersal et al., Garland Pub., 1988, pp. 205–06.

Kay, R. F. “Oligocene.” Encyclopedia of Human Evolution and Prehistory, edited by I. Tattersal et al., Garland Pub., 1988, pp. 392–94.

Kay, R. F. “Diet.” Encyclopedia of Human Evolution and Prehistory, edited by I. Tattersal et al., Garland Pub., 1988, pp. 155–59.

Kay, R. F. “Teeth.” Encyclopedia of Human Evolution and Prehistory, edited by I. Tattersal et al., Garland Pub., 1988, pp. 571–78.

Kay, R. F. “Parapithecidae.” Encyclopedia of Human Evolution and Prehistory, edited by I. Tattersal et al., Garland Pub., 1988, pp. 440–43.

Fleagle, J. G., and R. F. Kay. “The paleobiology of catarrhines.” Ancestors: The Hard Evidence, edited by E. Delson, Alan R. Liss, Inc., 1985, pp. 23–36.


Malinzak, Michael D., et al. “Locomotor head movements and semicircular canal morphology in primates.Proc Natl Acad Sci U S A, vol. 109, no. 44, Oct. 2012, pp. 17914–19. Pubmed, doi:10.1073/pnas.1206139109. Full Text Open Access Copy

Kay, Richard F. “Evidence for an Asian origin of stem anthropoids.Proceedings of the National Academy of Sciences of the United States of America, vol. 109, no. 26, June 2012, pp. 10132–33. Epmc, doi:10.1073/pnas.1207933109. Full Text Open Access Copy

Wilson, L. A. B., et al. “Testing a developmental model in the fossil record: Molar proportions in South American ungulates.” Paleobiology, vol. 38, no. 2, Mar. 2012, pp. 308–21. Scopus, doi:10.1666/11001.1. Full Text Open Access Copy

Allen, Kari L., and Richard F. Kay. “Dietary quality and encephalization in platyrrhine primates.Proceedings. Biological Sciences, vol. 279, no. 1729, Feb. 2012, pp. 715–21. Epmc, doi:10.1098/rspb.2011.1311. Full Text Open Access Copy

Malinzak, T., et al. “Predicting locomotion from the primate semicircular canal system.” Proceedings of the National Academy (Usa), vol. 109, 2012, pp. 17914–19. Open Access Copy



Kay, Richard F., et al. “Preliminary notes on a newly discovered skull of the extinct monkey Antillothrix from Hispaniola and the origin of the Greater Antillean monkeys.Journal of Human Evolution, vol. 60, no. 1, Jan. 2011, pp. 124–28. Epmc, doi:10.1016/j.jhevol.2010.09.003. Full Text Open Access Copy

Williams, Blythe A., et al. “Darwinius masillae is a strepsirrhine--a reply to Franzen et al. (2009).Journal of Human Evolution, vol. 59, no. 5, Nov. 2010, pp. 567–73. Epmc, doi:10.1016/j.jhevol.2010.01.003. Full Text Open Access Copy

Coleman, Mark N., et al. “Auditory morphology and hearing sensitivity in fossil New World monkeys.Anatomical Record (Hoboken, N.J. : 2007), vol. 293, no. 10, Oct. 2010, pp. 1711–21. Epmc, doi:10.1002/ar.21199. Full Text Open Access Copy


Mitchell, T. R. T., et al. “The role of binocular vision in primate locomotion.American Journal of Physical Anthropology, WILEY-LISS, 2006, pp. 132–33.

Vizcaíno, S. F., et al. “Morfología y paleobiología de vertebrados. Aplicación a los mamíferos de la Formación Santa Cruz (Mioceno temprano-medio), Patagonia, Argentina.” Ix Congreso Argentino De Paleontología Y Bioestratigrafía, 18  22 De Septiembre, Córdoba, Argentina, 2006.

Perry, J. M. G., et al. “Tooth root size and chewing muscle leverage in Homunculus, a Miocene Primate from Patagonia.Journal of Vertebrate Paleontology, vol. 26, 2006, p. 110A.

Kay, R. F., et al. “Observations on the olfactory system of Tremacebus harringtoni (Platyrrhini, early Miocene, Sacanana, Argentina) based on high resolution X-ray CT scans.American Journal of Physical Anthropology, WILEY-BLACKWELL, 2004, pp. 123–24.

Mitchell, T. R. T., et al. “The interorbital region of Dolichocebus gaimanensis (Platyrrhini, early Miocene, Argentina) based on high resolution X-ray CT imaging-phylogenetic implications.American Journal of Physical Anthropology, WILEY-BLACKWELL, 2004, pp. 148–148.

Vucetich, G., et al. “New Discoveries among the Oldest Rodents in South America: How Old and How Primitive?Journal of Vertebrate Paleontology, vol. 24, 2004, p. 125A.

Vucetich, G., et al. “Nuevos hallazgos entre los más antiguos roedores de América del Sur: una dispersion post-transición Eoceno-Oligoceno.” Resumenes De Comunicaciones De La Asociación Argentina De Paleontologia (Diamante, Argentina), vol. 2004, 2004.