Paleozoic Nymphal Wing Pads Support Dual Model of Insect Wing Origins
Paleozoic Nymphal Wing Pads Support Dual Model of Insect Wing Origins
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DOI：
10.1016/j.cub.2016.11.021
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发表时间：
2017-01-23
期刊：
影响因子：
9.2
通讯作者：
Engel, Michael S.
中科院分区：
文献类型：
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作者：
Prokop, Jakub;Pecharova, Martina;Engel, Michael S.
在昆虫进化的早期[1]，翅膀的出现是促成其非凡多样性的更关键的创新之一。尽管翅膀的显著性和重要性，这些结构的起源一直难以解决，并代表了进化生物学中的“令人憎恶的谜团”之一[2]。经过世纪的争论，这一问题被归结为两种相互竞争的观点，一种认为翅膀代表了胸背的延伸，另一种认为它们是从侧体壁衍生出来的。最近，基因组和发育数据[3-6]支持双重模型，代表了来自背侧和胸膜假设的元素的合并。在这里，我们揭示了石炭纪古网翅目昆虫的翅垫关节使用经典和高科技技术的关键信息。这些昆虫有三对翼垫，它们在内侧与胸部相连，但也与背部前后广泛相连（在现代昆虫中无法观察到的细节），支持它们的整体起源于胸部背部以及预期的内侧，胸膜系列腋骨片。我们的研究为昆虫翅膀的形成提供了支持，从胸背以及已经知道的节肢动物腿的胸膜元素。这些结果支持独特的，双重模型的昆虫翅膀的起源和收敛减少notal融合在更多的派生分支，大概是由于在发展过程中的翅膀旋转，他们有助于解决这个长期存在的争论。
The appearance of wings in insects, early in their evolution [1], has been one of the more critical innovations contributing to their extraordinary diversity. Despite the conspicuousness and importance of wings, the origin of these structures has been difficult to resolve and represented one of the "abominable mysteries" in evolutionary biology [2]. More than a century of debate has boiled the matter down to two competing alternatives one of wings representing an extension of the thoracic notum, the other stating that they are appendicular derivations from the lateral body wall. Recently, a dual model has been supported by genomic and developmental data [3-6], representing an amalgamation of elements from both the notal and pleural hypotheses. Here, we reveal crucial information from the wing pad joints of Carboniferous palaeodictyopteran insect nymphs using classical and high-tech techniques. These nymphs had three pairs of wing pads that were medially articulated to the thorax but also broadly contiguous with the notum anteriorly and posteriorly (details unobservable in modern insects), supporting their overall origin from the thoracic notum as well as the expected medial, pleural series of axillary sclerites. Our study provides support for the formation of the insect wing from the thoracic notum as well as the already known pleural elements of the arthropodan leg. These results support the unique, dual model for insect wing origins and the convergent reduction of notal fusion in more derived clades, presumably due to wing rotation during development, and they help to bring resolution to this long-standing debate.