N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences, Northern Dvina Emb. 23, 163000 Arkhangelsk, Russia. Northern Arctic Federal University, Northern Dvina Emb. 17, 163002 Arkhangelsk, Russia..
Fauna Flora International-Myanmar Programme, 34 D/9 San Yae Twin Street, Kaba Aye Pagoda Road, Bahan Township, 11201 Yangon, Myanmar. Biology Department, University of New Brunswick, PO Box 5050, 100 Tucker Park Road, Saint John, NB, E2L 4L5, Canada..
Zootaxa. 2021 May 21;4974(3):585595. doi: 10.11646/zootaxa.4974.3.7.
The freshwater leech family Salifidae Johansson has a Paleotropical range, with a hotspot of species richness in the Oriental Region, and a few species endemic to Africa, Madagascar, and Reunion. Barbronia gwalagwalensis Westergren Siddall, 2004 was thought to be a characteristic example of the latter group being a lineage endemic to South Africa. However, we found that this species also occurs in Asia (Myanmar and Korea). Our time-calibrated phylogeny based on the mitochondrial cytochrome c oxidase subunit I (COI) gene reveals that the split between the African and Asian populations of this species occurred in the mid-Pleistocene, approximately 1.3 Ma ago (95% HPD 0.7-2.1 Ma). The statistical biogeographic modeling indicates that a B. gwalagwalensis population in South Africa most likely originated due a long-distance dispersal event with a subsequent vicariance (probability = 88.9%). A Late Quaternary range extension towards South Africa is known to occur in some other freshwater taxa (e.g. the freshwater mussel Unio caffer Krauss species group), which agrees with our hypothesis on the ancient origin of the South African B. gwalagwalensis population. Conversely, we can assume that the African population of this species was recently introduced from Asia. If so, the high levels of genetic divergence between African and Asian populations could be a part of a more general phylogeographic pattern historically originated within the Asian subcontinent due to the isolation by orographic or marine barriers. These two alternative hypotheses need further research efforts, i.e. sampling and sequencing of other Barbronia taxa, the ranges of which are situated between South Africa and Southeast Asia, as well as of topotypes of B. weberi (Blanchard, 1897) from Indonesia. Finally, our results highlight that the salifid genus Barbronia Johansson originated in the Oriental Region and that these leeches share both recently and historically high potential for long-distance dispersal events.
淡水蛭科 Salifidae Johansson 的分布范围为古热带区，其中东方区的物种丰富度热点最为集中，此外还有一些非洲、马达加斯加和留尼汪的特有种。Westergren Siddall, 2004 年认为 Barbronia gwalagwalensis 是后者的一个典型例子，即该物种的谱系是南非特有的。然而，我们发现这种物种也出现在亚洲（缅甸和韩国）。我们基于线粒体细胞色素 c 氧化酶亚基 I（COI）基因构建的时间校准系统发育树表明，该物种的非洲和亚洲种群之间的分裂发生在中更新世，大约 130 万年前（95% HPD 0.7-2.1 Ma）。统计生物地理模型表明，南非的 B. gwalagwalensis 种群很可能是由于长途扩散事件和随后的地理隔离而产生的（概率=88.9%）。一些其他淡水分类群（例如淡水贻贝 Unio caffer Krauss 物种群）的南移扩展已知发生在晚第四纪，这与我们关于南非 B. gwalagwalensis 种群起源古老的假设相符。相反，我们可以假设该物种的非洲种群是最近从亚洲引入的。如果是这样，非洲和亚洲种群之间的高遗传分化可能是由于山脉或海洋屏障的隔离而在亚洲次大陆历史上产生的更广泛的系统发育格局的一部分。这两种替代假设需要进一步的研究努力，即对位于南非和东南亚之间的其他 Barbronia 分类群进行采样和测序，以及对来自印度尼西亚的 B. weberi（Blanchard，1897）的模式标本进行采样和测序。最后，我们的研究结果强调，Salifid 属 Barbronia Johansson 起源于东方区，并且这些水蛭都具有最近和历史上长距离扩散事件的高潜力。
