Evolutionary Patterns Within the Reef Coral Siderastrea in the Mio-Pliocene of the Dominican Republic

In 1972 Eldredge and Gould argued that the current evolutionary paradigm of the time (gradualism punctuated by stratigraphic gaps) did not explain patterns observed in the fossil record. They proposed an alternative hypothesis, punctuated equilibrium, which states that species lineages exhibit long periods of stasis and new species are formed during short periods of rapid evolutionary change (Eldredge and Gould, 1972; Gould, 2002). Since Eldredge and Gould’s original studies, several additional studies have found examples of phyletic gradualism, punctuated equilibrium, and various combinations of the two modes (e.g., Cheetham, 1986; Stanley and Yang, 1987; Geary, 1990; Nehm and Geary, 1994; Erwin and Anstey, 1995; Jackson and Cheetham, 1999; Jablonski, 2000; Nehm, 2005; Cheetham et al., 2007). The present study examines evolutionary patterns in the scleractinian reef coral Siderastrea (Blainville, 1830) to determine if the observed patterns follow phyletic gradualism or punctuated equilibrium.