Ephemeroptera

R. G. Beutel & S. N. Gorb, 2001, Ultrastructure of attachment specializations of hexapods (Arthropoda): evolutionary patterns inferred from a revised ordinal phylogeny, J. Zool. Syst. Evol. Research 39, pp. 177-207 : 179

6 Ephemeroptera

The tarsus is usually four­ or five­segmented ( Peters and Campbell 1991). The transformation of one of two claws into a thickened attachment organ (claw pad) is a characteristic feature found only in ephemeropterans ( Figs 3h , 4B ). Other adhesive structures are absent.

Figures

Fig. 3. Diversity of the leg attachment devices (gray­colored areas) in hexapods. (a) Arolium (smooth). (b) Pulvilli (smooth or hairy). (c) Empodial pulvillus (ep) (hairy). (d) Hairy adhesive soles of tarsomeres. (e) Eversible pretarsal bladder (smooth). (f) Eversible structure between tibia and tarsus (smooth). (g) Fossula spongiosa (hairy). (h) Euplantulae (eu) and claw pad (cp) (both smooth). (i) Tarsal thorns transformed into adhesive structures (th), claw pad (cp) (both smooth). (j) Adhesive claw setae

Fig. 4. Details of hexapod tarsi and pretarsi. (A) Lepisma saccharina (Zygentoma), foreleg, pretarsus, lateral aspect. (B) Paraleptophlebia sp. (Ephemeroptera), midleg, pretarsus, ventral aspect. (C) Blatella germanica (Blattodea), midleg, tarsus, ventro­lateral aspect. (D) Omocestus viridulus (Caelifera), foreleg, tarsus, ventral aspect. (E) Cercopis vulnerata (Auchenorrhyncha), midleg, pretarsus, ventro­lateral aspect. (F) Chrysoperla carnea (Neuroptera), pretarsus, ventral aspect. (G, H) Schistocerca gregaria (Caelifera), foreleg, arolium sagittal section, triple stain after Cason. (I) Brachyptera risi (Plecoptera), midleg, arolium, sagittal section, triple stain after Cason. (J) Cercopis vulnerata (Auchenorrhyncha), midleg, sagittal section, triple stain after Cason. Black arrows indicate ventral directions. AR, arolium; CP, claw pad; EU, euplantulae; RD, chitinous threads; TAR, tarsal segments; TI, tibia; UN, claw, UN1, ephemeropteran hook­like claw, UN2, ephemeropteran pad­bearing claw