Extinction biases inQuaternaryCaribbean lizards

Abstract

AbstractAimIntrinsic qualities that might affect extinction risk are not well understood for lizards (suborderLacertilia), a highly diverse and globally distributed group of reptiles (orderSquamata). We use theQuaternary fossil record ofCaribbean lizards to explore a commonly studied trait, body size, and its relationship to extinction.LocationTheCaribbean.MethodsWe compiled a body size database for over 300 species. We assessed whether the present‐day body size distribution of lizards differed from the body size distribution of the fossil record. We also compared body sizes of extant lizards with extinct lizards, and we used theInternationalUnion forConservation ofNature (IUCN)RedList to evaluate whether threatened species are larger than non‐threatened species. We examined whether there were geographic or phylogenetic biases to extinction in this system.ResultsQuaternary extinctions were size‐biased, with a higher incidence of extinction in large‐bodied lizards; the same relationship exists between threatened and non‐threatened present‐day lizards. Biases in the fossil record do not drive this trend, as the body sizes of present‐day lizards do not differ from those preserved in the fossil record. While there is no geographic variability in extinction, we find that there is lineage specificity, as the majority of extinctions occur within the family Leiocephalidae. At the family level, size alone does not explain extinction trends for most families, but our data suggest that large‐bodied species in each family have a higher extinction risk than their smaller counterparts.Main conclusionsSize‐biased extinction trends in lizards mirror phenomena in other taxonomic groups, but additional life‐history traits may play a role at the family level. We highlight the utility of fossil datasets in understanding extinction dynamics and underscore the urgency of a thorough assessment of extinction risk for insular lizards.