1) A kinetic model of Phanerozoic taxonomic diversity: I. Analysis of marine orders, 4(3), pp 223-251 (1978); 2) II. Early Phanerozoic families and multiple equilibria, 5(3), pp 222-251 (1979); 3) III. Post-Paleozoic families and mass extinctions 10(2), pp 246-267 (1984); 4) Alpha, beta, or gamma: where does all the diversity go? 14(3), pp 221-234 (1988); 5) Ten years in the library: new data confirm paleontological patterns, 19(1), pp 43-51 (1993)

1978, 1979, 1984, 1988, 1993. First editions.
SCARCE KEY PAPERS BY PIONEERING AMERICAN PALEONTOLOGIST.
Five journal articles: 1-3 (1978-1984) offprints and 4,5 (1988, 1993) extracts from original issues. Unmarked except for pen notation, "Cambrian time scale p 226" to cover of 1979 paper. Very good.
J. JOHN SEPKOSKI JR. (1948-1999) received his PhD from Harvard under the mentorship of Stephen Jay Gould. After 4 years on the faculty of the University of Rochester, he devoted the rest of his short career to the University of Chicago. He developed a kinetic model, extrapolated back into geological time and considered on a global scale, predicted (truncated) an exponential rise in faunal diversity after the origin of multicellular animals, followed by a constant equilibrium. Sepkoski showed that the fossil record of marine taxonomic orders from the late Precambrian — around 600 million years (Myr) ago — to the present is remarkably consistent with his model. This provides a simple explanation for the radiation of animal life into major groups during the Cambrian in terms of exponential diversification. But Sepkoski recognized that orders are only a crude proxy for species. Sepkoski's two-phase kinetic model involved separate evolutionary faunas — one characteristic of the Cambrian, the other of the rest of the Palaeozoic (510–245 Myr ago). The first was dominated by ecological generalists, and the second by more specialized taxonomic groups. This analysis confirmed that a plateau of diversity characterizes the Palaeozoic, and emphasized the profound effect of the extinctions at the end of the Permian (245 Myr ago). Sepkoski later confirmed that a third evolutionary fauna, the modern fauna, radiated mainly after this end-Permian extinction. Sepkoski's plot of diversity through time has become the familiar image of the history of life. Moving to the University of Chicago in 1978, Sepkoski turned his attention to extinctions, largely in collaboration with David Raup. Major extinctions disrupt equilibria, although the rebound patterns fit kinetic models of diversification. Raup and Sepkoski first identified mass extinctions statistically as peaks that are different from normal or background levels. If Sepkoski's models of diversification generated controversy in some quarters, it was nothing compared with the effect of the bombshell that he and Raup dropped in 1984. They announced that there is a significant periodicity in mass extinctions over the last 250 Myr. Their preliminary time-series analysis revealed that the 12 major extinctions occurred at regular intervals of 26 Myr, a discovery that created waves well beyond the palaeontological community. Sepkoski's main legacy is the patterns that he revealed in the history of life, and his analytical interpretations of diversity dynamics. He published a paper in 1993 entitled "Ten years in the library: new data confirm paleontological patterns" (Paleobiology 19, 43–51) (offered here), which demonstrated that his conclusions on diversification and extinction remained robust despite considerable refinement of the data, including additions and corrections." -- obituary by DEG Briggs, Nature, 5 August 1999. (Inventory #: 1557)