Abstract Extant alligator lizards of the genus Abronia are found in montane cloud forests and pine-oak forests of Mesoamerica and are iconic among the public and scientific communities. Here, we describe a fossilized partial skull from the Miocene of southern California (~12.5–11.0 Mya) that is the first definitive fossil and only recognized extinct species of Abronia. The locality of the fossil is substantially removed from the range of extant species of Abronia. This remarkable biogeographical discovery corroborates previous speculation that Abronia was distributed north of Mexico during the Neogene, a scenario that could not be inferred from the geographical ranges and phylogeny of the extant species alone. Additionally, the fossil preserves a distinctive morphology, osteoderm sails, that appears unique to the new taxon among alligator lizards. The finding emphasizes the importance of the fossil record for historical biogeography and could motivate new avenues of biogeographical research in Mesoamerica and the USA.

中文翻译：

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来自加利福尼亚中新世的装饰精美的鳄鱼蜥蜴化石（Squamata：Abronia）

摘要 现存的 Abronia 鳄鱼蜥存在于中美洲的山地云雾林和松橡树林中，是公众和科学界的标志性动物。在这里，我们描述了一个来自南加州中新世（~12.5-11.0 Mya）的部分头骨化石，它是第一个确定的化石，也是唯一公认的 Abronia 灭绝物种。化石的位置已从 Abronia 现存物种的范围中大大移除。这一非凡的生物地理发现证实了先前的推测，即新近纪期间 Abronia 分布在墨西哥北部，这种情况无法仅从现存物种的地理范围和系统发育中推断出来。此外，化石保留了独特的形态，骨皮帆，这似乎是鳄鱼蜥蜴中新分类群所独有的。这一发现强调了化石记录对历史生物地理学的重要性，并可能激发中美洲和美国生物地理学研究的新途径。