Wu Feixiang, He Dekui, Fang Gengyu, Deng Tao
Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China; Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing 100101, China.
Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
Sci Bull (Beijing). 2019 Apr 15;64(7):455-463. doi: 10.1016/j.scib.2019.03.029. Epub 2019 Mar 28.
The northward drift of the Indian Plate and its collision with Eurasia have profoundly impacted the evolutionary history of the terrestrial organisms, especially the ones along the Indian Ocean rim. Climbing perches (Anabantidae) are primary freshwater fishes showing a disjunct south Asian-African distribution, but with an elusive paleobiogeographic history due to the lack of fossil evidence. Here, based on an updated time-calibrated anabantiform phylogeny integrating a number of relevant fossils, the divergence between Asian and African climbing perches is estimated to have occurred in the middle Eocene (ca. 40 Ma, Ma: million years ago), a time when India had already joined with Eurasia. The key fossil lineage is †Eoanabas, the oldest anabantid known so far, from the upper Oligocene of the Tibetan Plateau. Ancestral range reconstructions suggest a Southeast Asian origin in the early Eocene (ca. 48 Ma) and subsequent dispersals to Tibet and then India for this group. Thereby we propose their westbound dispersal to Africa via the biotic bridge between India and Africa. If so, climbing perch precursors had probably followed the paleobiogeographical route of snakehead fishes, which have a slightly older divergence between African and Asian taxa. As such, our study echoes some recent molecular analyses in rejecting the previously held "Gondwana continental drift vicariance" or late Mesozoic dispersal scenarios for the climbing perches, but provides a unique biogeographical model to highlight the role of the pre-uplift Tibet and the docked India in shaping the disjunct distribution of some air-breathing freshwater fishes around the Indian Ocean.
印度板块向北漂移及其与欧亚大陆的碰撞，对陆地生物的演化历史产生了深远影响，尤其是印度洋沿岸的生物。攀鲈科鱼类是主要的淡水鱼，呈现出南亚 - 非洲间断分布的格局，但由于缺乏化石证据，其古生物地理历史难以捉摸。在此，基于整合了一些相关化石的更新后的时间校准攀鲈形类系统发育树，亚洲和非洲攀鲈之间的分化估计发生在始新世中期（约4000万年前，Ma：百万年前），此时印度已与欧亚大陆相连。关键的化石谱系是†始攀鲈，这是目前已知最古老的攀鲈科鱼类，来自青藏高原渐新世晚期。祖先分布区重建表明，该类群在始新世早期（约4800万年前）起源于东南亚，随后扩散到西藏，再到印度。因此，我们提出它们通过印度和非洲之间的生物桥梁向西扩散到非洲。如果是这样，攀鲈的祖先可能沿着鳢科鱼类的古生物地理路线，非洲和亚洲类群之间的分化时间稍早。这样一来，我们的研究呼应了最近的一些分子分析，否定了之前关于攀鲈的“冈瓦纳大陆漂移间断分布”或中生代晚期扩散假说，而是提供了一个独特的生物地理模型，以突出隆起前的西藏和对接后的印度在塑造印度洋周围一些呼吸空气的淡水鱼间断分布中的作用。
