Anatomically modern Carboniferous harvestmen demonstrate early cladogenesis and stasis in Opiliones
Anatomically modern Carboniferous harvestmen demonstrate early cladogenesis and stasis in Opiliones
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DOI：
10.1038/ncomms1458
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发表时间：
2011-08-01
影响因子：
16.6
通讯作者：
Sutton, Mark D.
中科院分区：
文献类型：
--
作者：
Garwood, Russell J.;Dunlop, Jason A.;Sutton, Mark D.
收割者是第三大最多样化的蛛形纲动物，是一个古老的群体，在除南极洲以外的所有大陆上都有发现。然而，陆地生活模式和皮革，矿化不良的外骨骼使保存不太可能，他们的化石记录是有限的。迄今为止发现的少数古生代物种看起来令人惊讶的现代，但保存得太差，无法进行明确的分类。在这里，我们使用高分辨率的X射线显微断层摄影术来描述两个新的收获者从石炭纪（类似于305百万年）的法国。由此产生的计算机模型允许任何古生代Opiliones的第一个系统发育分析，明确解决两个标本作为不同的现存谱系的成员，并提供佐证的分子估计的早古生代辐射内的顺序。此外，这些化石和现存的收割者之间的显着相似性意味着广泛的形态停滞的顺序。与其他节肢动物和一般的陆生节肢动物相比，收割者是最早进化出完全现代身体结构的群体之一。
Harvestmen, the third most-diverse arachnid order, are an ancient group found on all continental landmasses, except Antarctica. However, a terrestrial mode of life and leathery, poorly mineralized exoskeleton makes preservation unlikely, and their fossil record is limited. The few Palaeozoic species discovered to date appear surprisingly modern, but are too poorly preserved to allow unequivocal taxonomic placement. Here, we use high-resolution X-ray micro-tomography to describe two new harvestmen from the Carboniferous (similar to 305 Myr) of France. The resulting computer models allow the first phylogenetic analysis of any Palaeozoic Opiliones, explicitly resolving both specimens as members of different extant lineages, and providing corroboration for molecular estimates of an early Palaeozoic radiation within the order. Furthermore, remarkable similarities between these fossils and extant harvestmen implies extensive morphological stasis in the order. Compared with other arachnids-and terrestrial arthropods generally-harvestmen are amongst the first groups to evolve fully modern body plans.