Abstract Geography and climate have been the main drivers of evolution in recent geological epochs. While new lineages of species have been formed in the last millions of years (speciation) and others have vanished as a result of historical climate changes (extinction), some ancient lineages appear to have persisted to the present day without net diversification. In this paper, evolution of ancient lineages is addressed by combining phylogenetic and conservation approaches to test the concept of ‘endangered living fossil’ (ELF). Using endangered, monospecific genera as starting point, we propose three criteria to identify ELFs (in order): (1) scarcity and narrow distribution of populations, i.e. the species (and thus the genus) is categorised as either ‘endangered’ or ‘critically endangered’ using IUCN criteria; (2) evolutionary distinctiveness, i.e. phylogenetic singularity of a single-species lineage as a result of a null net diversification rate; (iii) ancient divergence, i.e. split from the closest extant relatives predating the dramatic climate changes of particular geological epochs (specifically changes since the Miocene-Pliocene boundary). The vascular flora of the Iberian Peninsula offers a suitable study system to reliably test the ELF concept. Indeed, time-calibrated phylogenies revealed that five of the six critically endangered, monospecific genera endemic to the Iberian Peninsula are ELFs. These five genera appear to have diverged from their closest relatives in the Oligocene (Gyrocaryum), Miocene (Avellara, Castrilanthemum, Gadoria) and around the Miocene-Pliocene boundary (Naufraga). This result entails long-term survival (with no net diversification) through at least three dramatic climate changes: the Messinian Salinity Crisis (late Miocene), the establishment of the mediterranean climate (Pliocene), and the glacial-interglacial cycles (Pleistocene). Using results from the literature, we found examples of ELFs for the mediterranean floras of California (Dodecahema), Chile (Avellanita, Gomortega, Legrandia) and other Mediterranean areas of Europe (Petagnaea, Phitosia). ELFs are unique and threatened lineages representing an exceptional evolutionary heritage, and therefore they should be prioritised in biodiversity research and conservation programs.

中文翻译：

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“濒危活化石”（ELFs）：经历剧烈气候变化时期的长期幸存者

摘要 地理和气候是近代地质时代演化的主要驱动力。虽然新的物种谱系在过去数百万年中形成（物种形成），而其他谱系由于历史气候变化（灭绝）而消失，但一些古老的谱系似乎一直持续到今天，没有净多样化。在本文中，通过结合系统发育和保护方法来测试“濒危活化石”（ELF）的概念，解决了古代谱系的进化问题。以濒临灭绝的单种属为起点，我们提出了三个标准来识别 ELF（按顺序）：（1）种群稀少且分布狭窄，即物种（因此属）被归类为“濒危”或“严重”使用 IUCN 标准濒危；(2) 进化独特性，i．e. 由于零净多样化率导致的单一物种谱系的系统发育奇异性；(iii) 古代分歧，即在特定地质时代的剧烈气候变化（特别是自中新世-上新世边界以来的变化）之前，与现存最亲缘关系的分裂。伊比利亚半岛的维管植物群提供了一个合适的研究系统来可靠地测试 ELF 概念。事实上，时间校准的系统发育表明，伊比利亚半岛特有的六个极度濒危的单一特异性属中有五个是 ELF。这五个属似乎与它们在渐新世（Gyrocaryum）、中新世（Avellara、Castrilanthemum、Gadoria）和中新世-上新世边界（Naufraga）附近的近亲分开。这一结果需要通过至少三个剧烈的气候变化长期生存（没有净多样化）：墨西拿盐度危机（晚中新世）、地中海气候的建立（上新世）和冰川-间冰期循环（更新世）。根据文献结果，我们找到了加利福尼亚（Dodecahema）、智利（Avellanita、Gomortega、Legrandia）和欧洲其他地中海地区（Petagnaea、Phitosia）地中海植物群的 ELF 示例。ELF 是独特且受到威胁的谱系，代表着特殊的进化遗产，因此应优先考虑生物多样性研究和保护计划。根据文献结果，我们找到了加利福尼亚（Dodecahema）、智利（Avellanita、Gomortega、Legrandia）和欧洲其他地中海地区（Petagnaea、Phitosia）地中海植物群的 ELF 示例。ELF 是独特且受到威胁的谱系，代表着特殊的进化遗产，因此应优先考虑生物多样性研究和保护计划。根据文献结果，我们找到了加利福尼亚（Dodecahema）、智利（Avellanita、Gomortega、Legrandia）和欧洲其他地中海地区（Petagnaea、Phitosia）地中海植物群的 ELF 示例。ELF 是独特且受到威胁的谱系，代表着特殊的进化遗产，因此应优先考虑生物多样性研究和保护计划。