Abstract
AbstractMany traits have been linked to extinction risk among modern vertebrates, including mode of life and body size. However, previous work has indicated there is little evidence that body size, or any other trait, was selective during past mass extinctions. Here, we investigate the impact of the Triassic–Jurassic mass extinction on early Archosauromorpha (basal dinosaurs, crocodylomorphs and their relatives) by focusing on body size and other life history traits. We built several new archosauromorph maximum‐likelihood supertrees, incorporating uncertainty in phylogenetic relationships. These supertrees were then employed as a framework to test whether extinction had a phylogenetic signal during the Triassic–Jurassic mass extinction, and whether species with certain traits were more or less likely to go extinct. We find evidence for phylogenetic signal in extinction, in that taxa were more likely to become extinct if a close relative also did. However, there is no correlation between extinction and body size, or any other tested trait. These conclusions add to previous findings that body size, and other traits, were not subject to selection during mass extinctions in closely‐related clades, although the phylogenetic signal in extinction indicates that selection may have acted on traits not investigated here.
Highlights
M A S S extinction events have played a major role in shaping macroevolutionary trends through time (Barnosky et al 2011)
Phylogenies, and have D likelihoods of 0. These two trees were used for the main analyses (Table 2), with supertree A used for the MCMCglmm procedure
Regardless, here we found no evidence for trait-related selection at this mass extinction event; a result that conforms with many previous analyses on other taxonomic groups, hitherto largely marine (Jablonski & Raup 1995; Smith & Jeffery 1998; Friedman 2009; Puttick et al 2017a)
Summary
M A S S extinction events have played a major role in shaping macroevolutionary trends through time (Barnosky et al 2011). One is to assume that the phylogenetic clustering of extinctions is a logical consequence of selection acting on phylogenetically conserved traits within closely related taxa (McKinney 1997) This approach is valuable in clades for which trait data are lacking, but phylogenies are relatively robust (Soul & Friedman 2017). Other traits relating to extinction risk during mass extinctions include diet and motility (Payne & Clapham 2012; Song et al 2012), with evidence that ecological specialists and slow dispersers cannot tolerate rapid environmental change (Erwin 1998; Jablonski 2005) Geographical factors such as range size and occupied latitude have been suggested, as these traits may influence survival during spatially heterogeneous disturbances (Erwin 1998; Powell 2007; Jablonski 2008). Most of these studies have focused on marine taxa, and extinction selectivity in the terrestrial realm in deep time has only recently come under investigation
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