The greatest hits of all time: the histories of dominant genera in the fossil record

Abstract

Certain taxa are noticeably common within collections, widely distributed, and frequently long-lived. We have examined these dominant genera as compared with rarer genera, with a focus on their temporal histories. Using occurrence data from the Paleobiology Database, we determined which genera belonging to six target groups ranked among the most common within each of 49 temporal bins based on occurrences. The turnover among these dominant taxa from bin to bin was then determined for each of these groups, and all six groups when pooled. Although dominant genera are only a small fraction of all genera, the patterns of turnover mimic those seen in much larger compilations of total biodiversity. We also found that differences in patterns of turnover at the top ranks among the higher taxa reflect previously documented comparison of overall turnover among these classes. Both dominant and nondominant genera exhibit, on average, symmetrical patterns of rise and fall between first and last appearances. Dominant genera rarely begin at high ranks, but nevertheless tend to be more common when they first appear than nondominant genera. Moreover, dominant genera rarely are in the top 20 when they last appear, but still typically occupy more localities than nondominant genera occupy in their last interval. The mechanism(s) that produce dominant genera remain unclear. Nearly half of dominant genera are the type genus of a family or subfamily. This is consistent with a simple model of morphological and phylogenetic diversification and sampling.

Enforced symmetry: the necessity of symmetric waxing and waning

“…It is also manifested in the averaged CG (center of gravity) measure introduced by Gould, Gilinsky & German (1987), which corresponds to the center of mass of the diversity of a taxon plotted against its relative lifespan. For most of the Phanerozoic and when averaged across multiple taxa, the CG metric is indistinguishable from 0.5 (Gould, Gilinsky & German, 1987; Plotnick & Wagner, 2018), in concordance with symmetric waxing and waning.…”

“…We demonstrate theoretically and through examples that mathematical constraints on transforming and averaging taxon trajectories through time have important implications for what can and cannot be derived from these trajectories in terms of mechanisms and patterns of changes in range size (Willis, 1922; Gaston, 1998; Webb & Gaston, 2000), occupancy, and diversity through time (Gould, Gilinsky & German, 1987; Foote, 2007; Foote et al, 2007; Liow & Stenseth, 2007; Pigot, Owens & Orme, 2012; Plotnick & Wagner, 2018). The constraints apply to all research questions in which symmetric waxing and waning has emerged and served to infer on macroecological patterns.…”

Peer Review #2 of "Enforced symmetry: the necessity of symmetric waxing and waning (v0.1)"

“…Manuscript to be reviewed metric is indistinguishable from 0.5 (Gould, Gilinsky and German, 1987;Plotnick and Wagner, 2018), in concordance with symmetric waxing and waning.…”

“…We demonstrate theoretically and through examples that mathematical constraints on transforming and averaging taxon trajectories through time have important implications for what can and cannot be derived from these trajectories in terms of mechanisms and patterns of changes in range size (Willis, 1922;Gaston, 1998;Webb and Gaston, 2000), occupancy, and diversity through time (Gould, Gilinsky and German, 1987;Foote, 2007;Foote et al, 2007;Liow and Stensteth, 2007;Pigot et al, 2012;Plotnick and Wagner, 2018). The constraints apply to all research questions in which symmetric waxing and waning has emerged and served to infer on macroecological patterns.…”

Peer Review #1 of "Enforced symmetry: the necessity of symmetric waxing and waning (v0.2)"

“…We demonstrate theoretically and through examples that mathematical constraints on transforming and averaging taxon trajectories through time have important implications for what can and cannot be derived from these trajectories in terms of mechanisms and patterns of changes in range size (Willis, 1922;Gaston, 1998;Webb and Gaston, 2000), occupancy, and diversity through time (Gould, Gilinsky and German, 1987;Foote, 2007;Foote et al, 2007;Liow and Stensteth, 2007;Pigot et al, 2012;Plotnick and Wagner, 2018). The constraints apply to all research questions in which symmetric waxing and waning has emerged and served to infer on macroecological patterns.…”