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

Vizcaíno, S. F., et al. “The armadillos (Mammalia, Xenarthra, Dasypodidae) of the Santa Cruz Formation (early-middle Miocene): An approach to their paleobiology.” Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 237, no. 2–4, Aug. 2006, pp. 255–69. Scopus, doi:10.1016/j.palaeo.2005.12.006. Full Text

Kay, Richard F., and Mario Alberto Cozzuol. “New platyrrhine monkeys from the Solimões Formation (late Miocene, Acre State, Brazil).Journal of Human Evolution, vol. 50, no. 6, June 2006, pp. 673–86. Epmc, doi:10.1016/j.jhevol.2006.01.002. Full Text

Tafforeau, P., et al. “Applications of X-ray synchrotron microtomography for non-destructive 3D studies of paleontological specimens.” Applied Physics A: Materials Science and Processing, vol. 83, no. 2, May 2006, pp. 195–202. Scopus, doi:10.1007/s00339-006-3507-2. Full Text

Fleagle, J. G., and R. F. Kay. “A new humerus of Homunculus from the Santa Cruz Formation, (early-middle Miocene, Patagonia).Journal of Vertebrate Paleontology, vol. 26, 2006, p. 62A.

Vizcaino, R. R., et al. “The armadillos (Mammalia, Xenarthra, Dasypodidae) of the Santa Cruz formation (early-middle Miocene).” Palaeogeography, Palaeoclimatology and  Paleoecology, vol. 237, 2006, pp. 255–69.

Kay, R. F. “A synopsis of the phylogeny and paleobiology of Amphipithecidae, South Asian middle and late Eocene primates.” Anthropological Science, vol. 113, no. 1, Apr. 2005, pp. 33–42. Scopus, doi:10.1537/ase.04S005. Full Text

Kay, R. F., et al. “Three newly discovered skulls of Homunculus patagonicus support its position as a stem platyrrhine and establish its diurnal arboreal folivorous habits.American Journal of Physical Anthropology, WILEY-LISS, Jan. 2005, pp. 127–127.

Kay, Richard F., et al. “Olfactory fossa of Tremacebus harringtoni (platyrrhini, early Miocene, Sacanana, Argentina): implications for activity pattern.The Anatomical Record. Part A, Discoveries in Molecular, Cellular, and Evolutionary Biology, vol. 281, no. 1, Nov. 2004, pp. 1157–72. Epmc, doi:10.1002/ar.a.20121. Full Text

Kohn, M. J., et al. “Climate stability across the Eocene-Oligocene transition, southern Argentina.” Geology, vol. 32, no. 7, July 2004, pp. 621–24. Scopus, doi:10.1130/G20442.1. Full Text


KAY, R. F., and H. H. COVERT. “SPECIES NUMBER DETERMINATION AND SPECIMEN ALLOCATION IN FOSSIL SAMPLES.” American Journal of Physical Anthropology, vol. 57, no. 2, WILEY-LISS, 1982, pp. 201–201.

KAY, R. F. “THE ADAPTIVE SIGNIFICANCE OF ENAMEL THICKNESS WITH IMPLICATIONS FOR HOMINID ORIGINS.” American Journal of Physical Anthropology, vol. 52, no. 2, WILEY-LISS, 1980, pp. 243–243.

SIMONS, E. L., et al. “RECENTLY RECOVERED OLIGOCENE APES FROM EGYPT.” American Journal of Physical Anthropology, vol. 52, no. 2, WILEY-LISS, 1980, pp. 279–279.

KAY, R. F., and W. S. SHEINE. “MODEL FOR COMPARISON OF MASTICATORY EFFICIENCY IN PRIMATES.” American Journal of Physical Anthropology, vol. 48, no. 3, WILEY-LISS, 1978, pp. 410–11.

KAY, R. F. “POST-OLIGOCENE EVOLUTION OF CATARRHINE DIETS.” American Journal of Physical Anthropology, vol. 47, no. 1, WILEY-LISS, 1977, pp. 141–42.

Cartmill, M., and R. F. Kay. Craniodental morphology and development and the problem of tarsier affinities. Vol. Abstract volume, 1976.

Hiemae, K., and R. F. Kay. “Trends in the evolution of primate mastication.Nature, vol. 240, no. 5382, 1972, pp. 486–87. Epmc, doi:10.1038/240486a0. Full Text

Kay, Richard F., et al. The Basicranial Anatomy of African Eocene/Oligocene Anthropoids. Are There Any Clues for Platyrrhine Origins? Springer New York, pp. 125–58. Crossref, doi:10.1007/978-0-387-73896-3_11. Full Text

Teaford, Mark F. “Back to the future.” Evolutionary Anthropology: Issues, News, and Reviews, vol. 13, no. 5, Wiley, pp. 198–99. Crossref, doi:10.1002/evan.20016. Full Text