CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO Laboratório Associado, Vairão, Portugal.
Departamento de Biologia, Faculdade de Ciencias da Universidade do Porto, Porto, Portugal.
BMC Ecol Evol. 2021 Nov 22;21(1):210. doi: 10.1186/s12862-021-01941-3.
The contribution of North Africa to the assembly of biodiversity within the Western Palaearctic is still poorly documented. Since the Miocene, multiple biotic exchanges occurred across the Strait of Gibraltar, underlying the high biogeographic affinity between the western European and African sides of the Mediterranean basin. We investigated the biogeographic and demographic dynamics of two large Mediterranean-adapted snakes across the Strait and assess their relevance to the origin and diversity patterns of current European and North African populations.
We inferred phylogeographic patterns and demographic history of M. monspessulanus and H. hippocrepis, based on range-wide multilocus data, combined with fossil data and species distribution modelling, under present and past bioclimatic envelopes. For both species we identified endemic lineages in the High Atlas Mountains (Morocco) and in eastern Iberia, suggesting their persistence in Europe during the Pleistocene. One lineage is shared between North Africa and southern Iberia and likely spread from the former to the latter during the sea-level low stand of the last glacial stage. During this period M. monspessulanus shows a sudden demographic expansion, associated with increased habitat suitability in North Africa. Lower habitat suitability is predicted for both species during interglacial stages, with suitable areas restricted to coastal and mountain ranges of Iberia and Morocco. Compiled fossil data for M. monspessulanus show a continuous fossil record in Iberia at least since the Pliocene and throughout the Pleistocene.
The previously proposed hypothesis of Pleistocene glacial extinction of both species in Europe is not supported based on genetic data, bioclimatic envelopes models, and the available fossil record. A model of range retraction to mountain refugia during arid periods and of glacial expansion (demographic and spatial) associated to an increase of Mediterranean habitats during glacial epochs emerges as a general pattern for mesic vertebrates in North Africa. Moreover, the phylogeographic pattern of H. hippocrepis conforms to a well-established biogeographic partition between western and eastern Maghreb.
北非对西古北区生物多样性形成的贡献仍未得到充分记录。从中新世以来，通过直布罗陀海峡发生了多次生物交流，这奠定了地中海盆地西部欧洲和非洲两侧之间高生物地理亲缘关系的基础。我们调查了跨越海峡的两种大型适应地中海的蛇的生物地理和人口动态，并评估了它们与当前欧洲和北非种群起源和多样性模式的相关性。
我们根据范围广泛的多基因数据推断了 M. monspessulanus 和 H. hippocrepis 的系统地理格局和种群历史，结合化石数据和物种分布模型，在当前和过去的生物气候环境下进行分析。对于这两个物种，我们在摩洛哥的高阿特拉斯山脉和伊比利亚东部地区发现了特有谱系，表明它们在更新世期间在欧洲得以延续。一个谱系在北非和伊比利亚南部共享，并且可能是在上一个冰期海平面低位期间从前者传播到后者的。在此期间，M. monspessulanus 显示出突然的种群扩张，与北非栖息地适宜性的增加有关。在间冰期阶段，预测两个物种的栖息地适宜性较低，适宜区域仅限于伊比利亚和摩洛哥的沿海和山脉。为 M. monspessulanus 汇编的化石数据显示，至少自上新世以来，伊比利亚就有连续的化石记录，贯穿整个更新世。
根据遗传数据、生物气候环境模型和可用的化石记录，先前提出的这两个物种在欧洲更新世冰川灭绝的假设是不成立的。在干旱时期退缩到山地避难所，以及在冰川时期与地中海栖息地增加相关的冰川扩张（种群和空间）的模型，作为北非湿润脊椎动物的一般模式出现。此外，H. hippocrepis 的系统地理格局符合西马格里布和东马格里布之间已确立的生物地理分区。
