Etmopteridae (lantern sharks) is the most species-rich family of sharks, comprising more than 50 species. Many species are described from few individuals, and re-collection of specimens is often hindered by the remoteness of their sampling sites. For taxonomic studies, comparative morphological analysis of type specimens housed in natural history collections has been the main source of evidence. In contrast, DNA sequence information has rarely been used. Most lantern shark collection specimens, including the types, were formalin fixed before long-term storage in ethanol solutions. The DNA damage caused by both fixation and preservation of specimens has excluded these specimens from DNA sequence-based phylogenetic analyses so far. However, recent advances in the field of ancient DNA have allowed recovery of wet-collection specimen DNA sequence data. Here we analyse archival mitochondrial DNA sequences, obtained using ancient DNA approaches, of two wet-collection lantern shark paratype specimens, namely Etmopterus litvinovi and E. pycnolepis, for which the type series represent the only known individuals. Target capture of mitochondrial markers from single-stranded DNA libraries allows for phylogenetic placement of both species. Our results suggest synonymy of E. benchleyi with E. litvinovi but support the species status of E. pycnolepis. This revised taxonomy is helpful for future conservation and management efforts, as our results indicate a larger distribution range of E. litvinovi. This study further demonstrates the importance of wet-collection type specimens as genetic resource for taxonomic research.

Etmopteridae（灯笼鲨）是物种最丰富的鲨鱼科，包括 50 多种。许多物种是从少数个体中描述的，并且样本的重新收集通常受到其采样地点偏远的阻碍。对于分类学研究，自然历史收藏中类型标本的比较形态分析一直是主要的证据来源。相比之下，很少使用 DNA 序列信息。大多数灯笼鲨收集标本，包括这些类型，在长期储存在乙醇溶液中之前都经过福尔马林固定。迄今为止，由于标本的固定和保存引起的 DNA 损伤已将这些标本排除在基于 DNA 序列的系统发育分析之外。然而，古代 DNA 领域的最新进展已经允许恢复湿收集标本 DNA 序列数据。鲽鱼和E. pycnolepis，其中类型系列代表唯一已知的个体。从单链 DNA 文库中靶向捕获线粒体标记可以对两个物种进行系统发育定位。我们的结果表明E. benchleyi和E. litvinovi但支持物种地位E. pycnolepis. 这种修订后的分类法有助于未来的保护和管理工作，因为我们的结果表明更大的分布范围E. litvinovi. 本研究进一步证明了湿采集型标本作为分类学研究遗传资源的重要性。