Branchiostomatidae (lancelets or amphioxus) comprises about 30 species, several of which are well-established models in evolutionary development. Our zoological and ecological knowledge of the family is nonetheless limited. Despite evident differences can be found among known populations, the taxonomy of Branchiostoma lanceolatum (type species of the genus Branchiostoma) has never been investigated with modern methods through its range in the northeastern Atlantic and Mediterranean Sea. We address this via a multilocus molecular approach and comparing specimens collected from different European populations. Results obtained here confirm the presence of a single species inhabiting the range between the topotypical localities of B. lanceolatum (Atlantic Ocean) and of its junior synonym B. lubricum (Mediterranean Sea), without evincing geographical structure between populations. This suggests that environment most likely drives the characteristics observed in different geographic areas. The long larval phase and the slow mutation rate in lancelets may have played a key role in the evolutionary history of this iconic species.

中文翻译：

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分子分类学证实，大西洋东北部和地中海存在着一种文昌鱼，Branchiostoma lanceolatum (Pallas, 1774)（头索动物门：Leptocardii：Branchiostoma lanceolatum）。


文昌鱼科（文昌鱼或文昌鱼）大约有 30 个物种，其中一些是进化发展中公认的模型。尽管如此，我们对该科的动物学和生态学知识仍然有限。尽管已知种群之间存在明显差异，但从未用现代方法对其分布于东北大西洋和地中海的文昌鱼（文昌鱼属的模式种）进行了分类学研究。我们通过多位点分子方法并比较从不同欧洲人群收集的标本来解决这个问题。这里获得的结果证实了单一物种的存在，栖息在 B. lanceolatum（大西洋）和其次要异名 B. lubricum（地中海）的典型地点之间的范围内，但没有表明种群之间的地理结构。这表明环境很可能驱动在不同地理区域观察到的特征。文昌鱼较长的幼虫期和缓慢的突变率可能在这一标志性物种的进化史上发挥了关键作用。