J. John Sepkoski

J. John Sepkoski, 50, dies at home in Hyde Park

University paleontologist J. John Sepkoski Jr., whose innovative work has had far-reaching impact on the scientific understanding of the fossil record and the diversification of animal life throughout much of Earth’s history, died Saturday, May 1, at his Hyde Park home of sudden heart failure related to high blood pressure. He was 50.

“Paleobiology is a small profession, so when we lose one of our very greatest, it’s really a tremendously painful experience,” said Harvard University paleontologist Stephen Jay Gould, with whom Sepkoski, Professor in Geophysical Sciences and Organismal Biology & Anatomy, studied as a graduate student. “Jack was one of the leading lights of the profession.”

One of Sepkoski’s major contributions was quantifying the nature of life’s diversity through time, said Douglas Erwin, a research paleontologist at the Smithsonian Institution in Washington, D.C., and editor of the journal Paleobiology. “He exhaustively documented the ups and downs of life through the last 600 million years. By collecting the data and developing a series of statistical methods to study it, he gave us a new way of understanding the history of life in the oceans.”

Sepkoski’s work is discussed in the book Mystery of Mysteries: Is Evolution a Social Construction? by Michael Ruse, published this year by Harvard University Press. “One of the first chapters is on Charles Darwin, and one of the last chapters is on Jack,” said David Jablonski, Professor in Geophysical Sciences.

Sepkoski was born July 26, 1948, in Presque Isle, Maine. He earned his B.S. degree in geology, magna cum laude, from the University of Notre Dame in 1970 and his Ph.D. in geological sciences from Harvard University in 1977. His Ph.D. research was on the field geology and paleontology of South Dakota’s Black Hills.

He taught at the University of Rochester from 1974 to 1978. He was appointed Assistant Professor in the Department of Geophysical Sciences at the University in 1978. Sepkoski attained the rank of Associate Professor in 1982 and Professor in 1986. He also had been a research associate at the Field Museum of Natural History.

The Paleontological Society bestowed its Charles Schuchert Award upon Sepkoski in 1983. He served a term as the society’s president from 1995 to 1996 and founded the Paleontological Society International Research Program, or PalSIRP, the society’s program for assisting paleontologists in the countries of the former Soviet Union through small competitive grants.

He was co-editor of the journal Paleobiology, regarded as the major journal of his field, from 1983 to 1986 and a member of its editorial board from 1987 to 1989.

Sepkoski is survived by his wife, Christine Janis, Providence, R.I.; his son, David Sepkoski, Minneapolis, Minn.; his father, Joseph Sepkoski, Sparta, N.J.; two sisters, Carol Sepkoski, Cambridge, Mass., and Diane Karl, Cedar Brook, N.J.; and his former wife, Maureen Meter, Chicago.

Arrangements for a public memorial service in June or July are pending. In lieu of flowers, donations may be made to PalSIRP, c/o Dr. Thomas W. Kammer, Treasurer, Paleontological Society, Dept. of Geology and Geography, West Virginia University, P.O. Box 6300, Morgantown, WV