CLADOENDESIS OF EPHEMEROPTERA
Figure 8. Reduction of wings and pterothorax among mayflies.
A–B – Siphlonurus/fg3 spp., mayflies with most usual plesiomorphic proportions: A – general view; B – median section of pterothorax. C–D – Turbanoculata, mayflies with reduced hind wings: C – vernus Curtis 1834 [Baetis], mayfly with vestigial hind wings; D – median section of pterothorax of Cloeon/fg* diptera [Ephemera], mayfly without hind wings. E–F – individual variability of wing size in an undescribed short-winged species of Rhithrogena/fg2 from Chukotka (River Amguema 12 km below meteorological station, 1 IX 1976, leg. E. Makarchenko). (A – from Tshernova 1964, B – from Kluge 2000, C – from Kluge 1997d).
Abbreviations: MTm2 – median tergal muscle of mesothorax; MTm3 – median tergal muscle of metathorax; PhM – middle phragma; SA.Sm – subalar-sternal muscle; S.ESm2 – scuto-episternal muscle of mesothorax; S.ESm3 – scuto-episternal muscle of metathorax; S.LPNm – scuto-lateropostnotal muscle.