Data from: Lepidosaurian diversity in the Mesozoic–Paleogene: the potential roles of sampling biases and environmental drivers

Lepidosauria is a speciose clade with a long evolutionary history, but there have been few attempts to explore its taxon-richness through time. Here we estimate patterns of terrestrial lepidosaur genus diversity for the Triassic–Paleogene (252–23 Ma), and compare observed and sampling-corrected richness curves generated using Shareholder Quorum Subsampling and classical rarefaction. Generalized least-squares regression (GLS) is used to investigate the relationships between richness, sampling and environmental proxies. We found low levels of richness from the Triassic until the Late Cretaceous (except in the Kimmeridgian–Tithonian of Europe). High richness is recovered for the Late Cretaceous of North America, which declined across the K–Pg boundary but remained relatively high throughout the Paleogene. Richness decreased following the Eocene–Oligocene Grande Coupure in North America and Europe, but remained high in North America and very high in Europe compared to the Late Cretaceous; elsewhere data are lacking. GLS analyses indicate that sampling biases (particularly the number of fossil collections per interval) are the best explanation for long-term face-value genus richness trends. The lepidosaur fossil record presents many problems when attempting to reconstruct past diversity, with geographic sampling biases being of particular concern, especially in the Southern Hemisphere.

鳞龙类（Lepidosauria）是一个物种丰富度极高的演化支，拥有漫长的演化历史，但此前鲜有研究尝试探究其随时间变化的类群丰富度。本研究估算了三叠纪-古近纪（252 Ma~23 Ma）期间陆地鳞龙类的属级多样性变化模式，并对比了通过股东配额子采样（Shareholder Quorum Subsampling）与经典稀疏法生成的观测丰富度曲线与采样校正后丰富度曲线。研究采用广义最小二乘回归（GLS）分析了丰富度、采样强度与环境代用指标之间的关联。结果显示，从三叠纪至白垩纪晚期，类群丰富度整体处于较低水平（欧洲基默里奇阶-提通阶时期除外）。北美白垩纪晚期的类群丰富度达到峰值，随后在K-Pg界线处出现下降，但在整个古近纪仍维持在相对较高的水平。北美与欧洲的类群丰富度在始新世-渐新世大更替（Grande Coupure）后出现下降，但相较于白垩纪晚期，北美丰富度仍处于较高水平，欧洲则维持在极高水平；其余区域则缺乏相关数据。GLS分析表明，采样偏差（尤其是各时间间隔内的化石藏品数量）是解释长期表观属级丰富度变化趋势的最佳因素。在重建过去生物多样性的过程中，鳞龙类化石记录存在诸多问题，其中地理采样偏差尤为值得关注，南半球地区的相关问题尤其突出。