The extinct Gomphotheriidae is the only proboscidean family that colonized South America. The phylogenetic position of the endemic taxa has been through several revisions using morphological comparisons. Morphological studies are enhanced by paleogenetic analyses, a powerful tool to resolve phylogenetic relationships; however, ancient DNA (aDNA) preservation decreases in warmer regions. Despite the poor preservation conditions for aDNA in humid, sub-tropical climates, we recovered ∼3,000 bp of mtDNA of Notiomastodon platensis from the Arroyo del Vizcaíno site, Uruguay. Our calibrated phylogeny places Notiomastodon as a sister taxon to Elephantidae, with a divergence time of ∼13.5 Ma. Additionally, a total evidence analysis combining morphological and paleogenetic data shows that the three most diverse clades within Proboscidea diverged during the early Miocene, coinciding with the formation of a land passage between Africa and Eurasia. Our results are a further step toward aDNA analyses on Pleistocene samples from subtropical regions and provide a framework for proboscidean evolution.

已灭绝的 Gomphotheriidae 是唯一殖民南美洲的长鼻科。地方性类群的系统发育位置已经通过形态学比较进行了多次修订。古遗传学分析增强了形态学研究，古遗传学分析是解决系统发育关系的有力工具；然而，在较温暖的地区，古代 DNA (aDNA) 的保存会减少。尽管在潮湿的亚热带气候条件下，aDNA 的保存条件很差，但我们还是从乌拉圭阿罗约德尔比斯卡伊诺遗址恢复了 3,000 bp 的Notiomastodonplatensis mtDNA。我们经过校准的系统发育将Notiomastodon视为象科的姊妹分类单元，其分歧时间约为13.5 Ma。此外，结合形态学和古遗传学数据的全面证据分析表明，长鼻目中三个最多样化的进化枝在中新世早期出现分歧，恰逢非洲和欧亚大陆之间陆地通道的形成。我们的结果是对亚热带地区更新世样本进行DNA分析的又一步，并为长鼻类动物的进化提供了框架。