Teiid lizards are well represented in the fossil record and are common components of modern ecosystems in North and South America. Many fossils were referred to the cnemidophorine teiid group (whiptails, racerunners and relatives), particularly from North America. However, systematic interpretations of morphological features in cnemidophorines were hampered by the historically problematic taxonomy of the clade, and the biogeography and chronology of cnemidophorine evolution in North America is poorly understood from the fossil record. Few fossil cnemidophorines were identified with an apomorphy-based diagnosis, and there are almost no fossil cnemidophorines that could be used to anchor node calibrations. Here, I describe a cnemidophorine from the Miocene Ogallala Group of Nebraska and diagnose the fossil using apomorphies. In that process, I clarify the systematic utility of several morphological features of cnemidophorine lizards. I refer the fossil to the least inclusive clade containing Aspidoscelis, Holcosus and Pholidoscelis. The most conservative minimum age of the locality of the fossil is a fission-track date of 6.3 Ma, but mammal biochronology provides a more refined age of 9.4 Ma, which can be used as a minimum age for the crown cnemidophorine clade in divergence time analyses. The fossil indicates that a cnemidophorine lineage that does not live in Nebraska today inhabited the area during the Miocene. I refrain from naming a new taxon pending discovery of additional fossil material of the lineage to which the fossil belonged.

泰伊德蜥蜴在化石记录中有很好的代表，是北美和南美现代生态系统的常见组成部分。许多化石都属于 cnemidophorine teiid 类群（鞭尾鱼、赛跑鸟及其近亲），尤其是来自北美的化石。然而，对cnemidophorine形态特征的系统解释受到历史上有问题的进化枝分类学的阻碍，并且从化石记录中对北美cnemidophorine进化的生物地理学和年代学了解甚少。很少有化石 cnemidophorine 通过基于无源性的诊断被识别出来，并且几乎没有化石 cnemidophorine 可用于锚定节点校准。在这里，我描述了来自内布拉斯加州中新世奥加拉拉群的一种cnemidophorine，并使用apomorphies诊断了该化石。在此过程中，我阐明了cnemidophorine蜥蜴的几个形态特征的系统用途。我将这块化石称为包含性最差的分支，包括Aspidoscelis、Holcosus和Pholidoscelis。化石所在地最保守的最小年龄是裂变径迹日期6.3 Ma，但哺乳动物生物年代学提供了更精确的年龄9.4 Ma，这可以用作分歧时间分析中冠cnemidophorine分支的最小年龄。该化石表明，在中新世期间，一个不生活在今天内布拉斯加州的cnemidophorine谱系曾居住在该地区。在发现该化石所属谱系的其他化石材料之前，我不会命名一个新的分类单元。