Night lizards survived the Cretaceous-Palaeogene mass extinction near the asteroid impact.

Abstract

Discovering traits that facilitate survival through mass extinctions is of great interest to scholars of macroevolution. Here, we show that the common ancestry of xantusiid night lizards, a species-poor lineage with conserved anatomy, precedes the Cretaceous-Palaeogene boundary. We reconstruct the geographic distribution of the stem lineages of three living genera, Lepidophyma, Xantusia, and the monospecific Cricosaura, as surrounding the Gulf of Mexico, identifying Xantusiidae as the only tetrapod crown clade currently known to have survived the Cretaceous-Palaeogene mass extinction proximal to the site of the bolide impact on the Yucatan Peninsula. By integrating data from living species, we show that the night lizard lineages that witnessed the bolide impact likely possessed low litter or clutch sizes of 1-2 individuals, challenging prevailing hypotheses derived from studies focused on species-rich clades such as birds and mammals about what traits are necessary to survive a terrestrial mass extinction.