Data from: Phylogenetic relationships within the lizard clade Xantusiidae: using trees and divergence times to address evolutionary questions at multiple levels

Xantusiidae (night lizards) is a clade of small-bodied, cryptic lizards endemic to the New World. The clade is characterized by several features that would benefit from interpretation in a phylogenetic context, including: (1) monophyletic status of extant taxa Cricosaura, Lepidophyma, and Xantusia; (2) a species endemic to Cuba (Cricosaura typica) of disputed age; (3) origins of the parthenogenetic species of Lepidophyma; (4) pronounced micro-habitat differences accompanied by distinct morphologies in both Xantusia and Lepidophyma; and (5) placement of Xantusia riversiana, the only vertebrate species endemic to the California Channel Islands, which is highly divergent from its mainland relatives. This study incorporates extensive new character data from multiple gene regions to investigate the phylogeny of Xantusiidae using the most comprehensive taxonomic sampling available to date. Parsimony and partitioned Bayesian analyses of more than 7 kb of mitochondrial and nuclear sequence data from 11 loci all confirm that Xantusiidae is monophyletic, and comprises three well-supported clades: Cricosaura, Xantusia, and Lepidophyma. The Cuban endemic Cricosaura typica is well supported as the sister to all other xantusiids. Estimates of divergence time indicate that Cricosaura diverged from the (Lepidophyma + Xantusia) clade ∼81 million years ago (Ma), a time frame consistent with the separation of the Antilles from North America. Our results also confirm and extend an earlier study suggesting that parthenogenesis has arisen at least twice within Lepidophyma without hybridization, that rock-crevice ecomorphs evolved numerous times (>9) within Xantusia and Lepidophyma, and that the large-bodied Channel Island endemic X. riversiana is a distinct, early lineage that may form the sister group to the small-bodied congeners of the mainland.

夜蜥科（Xantusiidae）是一类小型、具隐蔽性的蜥蜴演化支，仅分布于新大陆。该演化支存在多项有待结合系统发育背景进行解析的特征，具体包括：(1) 现生类群圆鼻蜥属（Cricosaura）、鳞睑蜥属（Lepidophyma）以及夜蜥属（Xantusia）的单系性；(2) 古巴特有种圆鼻蜥（Cricosaura typica）的演化年代尚存争议；(3) 鳞睑蜥属单性生殖物种的起源；(4) 夜蜥属与鳞睑蜥属均存在显著的微生境分化，并伴随对应的形态差异；(5) 加州海峡群岛特有脊椎动物物种河生夜蜥（Xantusia riversiana）的系统发育定位，该物种与其大陆近缘类群差异显著。本研究整合了来自多个基因区域的大量全新性状数据，采用目前最全面的分类群采样策略，对夜蜥科的系统发育关系展开探究。研究对11个基因位点、总计超过7kb的线粒体与核基因序列数据进行简约法（Parsimony）和分区贝叶斯分析（partitioned Bayesian analyses），结果均证实夜蜥科为单系群，且包含三个支持度较高的演化支：圆鼻蜥属、夜蜥属与鳞睑蜥属。古巴特有种圆鼻蜥被高度支持为其余所有夜蜥科物种的姊妹群。分化时间估算结果显示，圆鼻蜥属与（鳞睑蜥属+夜蜥属）演化支的分化时间约为8100万年前，这一时间框架与安的列斯群岛与北美大陆的分离时间相吻合。本研究结果同时验证并拓展了此前一项研究的结论：单性生殖在鳞睑蜥属中至少独立起源两次且未伴随杂交事件；岩缝生态型在夜蜥属与鳞睑蜥属中独立演化超过9次；体型较大的海峡群岛特有物种河生夜蜥是一个独立的早期演化支，可能构成大陆小型同属物种的姊妹群。