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 Siphlur...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.展开更多
文摘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.
