1. The sand tiger shark (Carcharias taurus) is a coastal species distributed in temperate and sub‐tropical waters, classified as ‘Vulnerable’ at global level and ‘Critically endangered’ in eastern Australia, south‐western Atlantic Ocean, and Mediterranean Sea. Six populations (north‐western Atlantic, Brazil, South Africa, Japan, eastern Australia, and western Australia) with low genetic diversity and limited gene flow were identified worldwide, but genetic information for many other geographic areas are still missing. Specifically, this species is listed in several reports as part of the Mediterranean fauna, even if there has been a lack of catches and sightings in recent years in this basin. To clarify the origin of C. taurus individuals caught in the past in the Mediterranean Sea, historical samples were genetically analysed.
2. Nine samples with certain Mediterranean origin were collected from different European museums. DNA was extracted and ~600 bp of the mitochondrial DNA control region were amplified using eight overlapping species‐specific primer pairs. Sequences obtained were aligned with all the haplotypes globally known so far.
3. Genetic analysis revealed the misidentification of one museum specimen. Among the remaining Mediterranean historical samples, three different haplotypes were recovered. Two of them previously observed only in South Africa and one described in both South African and Brazilian populations.
4. Results suggest a genetic relationship between Mediterranean sand tiger sharks and those from the western Indian Ocean. According to previous studies, we hypothesized that, during the Pleistocene, the cold Benguela upwelling barrier was temporarily reduced allowing the passage of C. taurus individuals from the Indian to Atlantic Ocean. After the restoration of this phylogeographic barrier some individuals were trapped in the Atlantic Ocean and probably migrated northward colonizing the western African coasts and the Mediterranean Sea.

中文翻译：

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历史DNA作为对地中海沙虎鲨（Carcharias taurus，Lamniformes：Odontaspididae）进行遗传学表征的工具：一种物种可能已从该盆地消失

1. 虎鲨（Carcharias taurus）是分布在温带和亚热带水域的沿海物种，在全球范围内被列为“脆弱”，在澳大利亚东部，西南大西洋和地中海地区被列为“极度濒危”。在世界范围内发现了六种遗传多样性低且基因流受限的种群（西北大西洋，巴西，南非，日本，东澳大利亚和西澳大利亚），但许多其他地理区域的遗传信息仍然缺失。具体来说，该物种在几份报告中都被列为地中海动物区系的一部分，即使近年来该盆地缺乏捕获物和目击者也是如此。澄清金牛座的起源 过去在地中海捕获的个体，对历史样本进行了遗传分析。
2. 从某些欧洲博物馆收集了九种具有某些地中海血统的样品。提取DNA，并使用八个重叠的物种特异性引物对扩增约600 bp的线粒体DNA控制区。将获得的序列与迄今为止全球已知的所有单倍型进行比对。
3. 遗传分析揭示了一个博物馆标本的错误识别。在其余的地中海历史样本中，回收了三种不同的单倍型。其中有两个以前只在南非观察到，一个在南非和巴西人​​口中都见过。
4. 结果表明，地中海沙虎鲨与印度洋西部鲨鱼之间存在遗传关系。根据以前的研究，我们假设，在更新世期间，本格拉的冷上升流屏障被暂时减少，从而使金牛（C. taurus）个体从印度流向大西洋。恢复了这种地理学屏障之后，一些人被困在大西洋中，并可能向北迁移，定居在西非海岸和地中海。