FIGURE 3.13 Size frequency distribution of geographic ranges in reef stomato-pods (Lat, latitude; Long, longitude). Other measures of geographic range size [latitudinal distance, longitudinal distance, square root of (latitude × longitude)²] yield a similar plot.

(Gaston and Blackburn, 1996). (v) Frequency distributions for geographic ranges are shifted toward small ranges [Gaston (1994, 1998), Gaston and Chown (1999), and Roberts and Hawkins (1999), but see Hughes et al. (2002)]. Commonalities in patterns of body size, life history, and distribution between reef stomatopods and other taxa suggest that the relationship between life history mechanisms and patterns of diversity and endemism we find in benthic reef organisms also may operate in other systems.

Factors that influence the relative rates of speciation vs. extinction control the geography of species diversity and endemism. This section will review briefly some of the factors thought to determine rates of extinction and speciation in marine and other organisms, and Discussion will apply these generalities to the patterns of diversity and endemism observed in IWP reef stomatopods.

Species or genera that are widespread, abundant, and dispersive resist extinction in both marine and terrestrial environments and both fossil and contemporary lineages (Jablonski, 1986a,b, 1987, 1991; Gaston, 1994; Hubbell, 2001; Jablonski et al., 2003a). In addition to geographic range, which is sufficient on its own to explain species survival (Jablonski and Hunt, 2006), the presence of long-lived larvae and species richness of the clade confer resistance to background extinction in fossil marine bivalves (Jablonski, 1986a, 1991). Broad distribution of the clade confers protection against mass extinction (Jablonski, 1986a, 1991, 2007; Powell, 2007a). In addition, latitudinal distribution affects extinction, with the tropics—especially reef faunas—being subject to repeated upheaval, particularly during mass extinctions (Jablonski, 1991, 1993; Powell, 2007b).