Abstract:
The Late Paleozoic acquisition of wings in insects represents one of the key steps in arthropod evolution. While the origin of wings has been a contentious matter for nearly two centuries, recent evolutionary developmental studies suggest either the participation of both tergal and pleural tissues in the formation of wings1 or wings originated from exites of the most proximal leg podite incorporated into the insect body wall.2 The so-called \"dual hypothesis\" for wing origins finds support from studies of embryology, evo-devo, and genomics, although the degree of the presumed contribution from tergal and pleural tissues differ.3-6 Ohde et al.,7 confirmed a major role for tergal tissue in the formation of the cricket wing and suggested that \"wings evolved from the pre-existing lateral terga of a wingless insect ancestor.\" Additional work has focused on identifying partial serially homologous structures of wings on the prothorax8,9 and abdominal segments.10 Thus, several studies have suggested that the prothoracic horns in scarab beetles,9 gin traps of tenebrionid and scarab beetle pupae,11,12 or abdominal tracheal gills of mayfly larvae1,13 evolved from serial homologues of wings. Here, we present critical information from abdominal lateral outgrowths (flaps) of Paleozoic palaeodictyopteran larvae, which show comparable structure to thoracic wings, consisting of cordate lateral outgrowths antero-basally hinged by muscle attachments. These flaps therefore most likely represent wing serial homologues. The presence of these paired outgrowths on abdominal segments I-IX in early diverging Pterygota likely corresponds to crustacean epipods14,15 and resembles a hypothesized ancestral body plan of a \"protopterygote\" model.
摘要:
晚古生代昆虫获得翅膀是节肢动物进化的关键步骤之一。虽然翅膀的起源近两个世纪以来一直是一个有争议的问题,最近的进化发展研究表明,翼部和胸膜组织都参与了翅膀的形成1,或者是由融合到昆虫体壁中的最近端腿足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足足evo-devo,和基因组学,尽管来自Tergal和胸膜组织的推定贡献程度不同3-6Ohde等人。,7证实了Tegal组织在the翼形成中的主要作用,并表明\“翼是从无翼昆虫祖先的预先存在的外侧Terga进化而来的。\“其他工作集中在确定前胸8,9和腹部节段上翅膀的部分连续同源结构。10因此,几项研究表明,圣甲虫的前胸角,9个金银虫和金龟子甲虫p的杜松子酒陷阱,mayfly幼虫的11,12或腹部气管g1,13从翅膀的系列同源物进化而来。这里,我们提供了来自古生代古双翅目幼虫腹部侧向生长(皮瓣)的关键信息,显示出与胸翼相当的结构,由心形侧向生长物组成,前基底由肌肉附件铰接。因此,这些襟翼最有可能代表机翼系列同源物。在早期发散的翼状纲中,这些配对的外植体在腹段I-IX上的存在可能对应于甲壳类动物的表皮14,15,并且类似于“前翼体”模型的假设的祖先身体计划。