《环境昆虫学报》

由于蜉蝣成虫翅基结构变形大，起始状态难以确定，其原始脉相及其起源过程仍未有清楚呈现。不过，少数中国大型蜉蝣稚虫翅芽的基部却保留着一些原始线索，如中国古丝蜉Siphluriscus chinensis、长茎蜉Ephemera pictipennis和戴氏短丝蜉Siphlonurus davidi。总体上，它们表明：蜉蝣翅脉中的亚前缘脉弓（Subcostal brace）可能起源于亚前缘脉前支（ScA）；径脉（Radius，R）与中脉（Media，M）在基部就完全合并，后中脉（Media Posterior，MP）最先离开它们的主干，然后是基部合并在一起的径分脉（Radial Section，Rs）和前中脉（Media Anterior，MA)；肘脉（Cubitus，Cu）完全独立；臀脉（Anal，A）的气管起源于肘脉中的气管。在蜉蝣翅中，所有纵脉都有独立的翅基骨片但它们都不能活动，而是与纵脉完全愈合在一起，特别是在径脉（R）与中脉（M）的基部形成一个较大的骨板，所有这些骨片与骨板又因翅基的骨化和硬化而连接成块，因而蜉蝣翅不具有折叠的结构基础。从系统发育的角度看，蜉蝣目内不同的演化支系具有不同的脉相，它缘于各纵脉在翅基的位置不同，如亚前缘脉弓（ScA）与翅前缘的距离以及肘脉（Cu）与中脉（M）的距离。而对于有翅昆虫的三大支而言，蜉蝣似乎与新翅类较接近，因为它们的翅基都具有3块腋片且径脉（R）与中脉（M）在基部合并，而蜻蜓翅基不具腋片且中脉（M）与肘脉（Cu）合并，似乎与蜉蝣的关系较远，故从翅基结构与脉相来看，“古翅类”（=蜉蝣目+蜻蜓目）应该不是单系群。

英文摘要:

The original or primitive venation of mayflies was not presented clearly upon living materials before, this mostly results from the deform of mayfly imaginal wingbase. Some nymphs of large mayflies of China, like Siphluriscus chinensis, Ephemera pictipennis and Siphlonurus davidi, however, show some clues. Together, they demonstrate that in mayflies, subcostal brace maybe originated from longitudinal vein Anterior Subcostal (ScA), stems of Radius (R) and Media (M) are always fused at base, Media Posterior (MP) leave them first, then the branch of Rs (Radial Section)+MA (Media Anterior), Cubitus (Cu) disconnected to any other veins. Additionally, all longitudinal veins of mayflies fused with their sclerotized base respectively but without any moveable sclerite. Instead, base of R+M of mayflies sclerotized into a single one big plate, and all sclerites of wingbase are fused together rigidly by sclerotized wingbase, which disables any possible folding of mayfly wings. Phylogenetically, in the order Ephemeroptera, the different positions of ScA and Cu leaded to different and diverse venations and lineages of Ephemeroptera. In the Pterygota, the Ephemeroptera has the same fused pattern of R+M and three axillary sclerites as the Neoptera while the Odonata has the fused Cu+M, which disproves the monophyly of Paleoptera.

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