CLADOENDESIS OF EPHEMEROPTERA

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Autapomorphies of Elassoneuria/fg1.

(1) On fore wing MA has a long stem and furcates nearer to middle of wing, than to its base; RSp and MP₁ are close not only to branches MA₁ and MA₂ correspondingly [see Geminovenata (3)], but to the stem of M as well; thus MA with RSp and MP₁ form a Y-shape figure (Demoulin 1952b: Fig.2; Kluge 2004: Fig.49:A). In all other Geminovenata MA bifurcates near base (i.e. MA with RSp and MP₁ form V-shaped figure).

For Euephemeroptera in general, and particularly for Discoglossata, position of MA bifurcation near wing middle is a plesiomorphy, but in Elassoneuria/g1 elongation of stem of MA, probably, appeared secondarily [see Geminovenata (2)], that is testified by unique position of RSp and MP₁.

(2) On fore wing double vein RSa+iRS [see Geminovenata (2)] is lost (Kluge 2004: Fig.49:A). Non-unique apomorphy: this vein independently reduced in Homoeoneuria/g2 (but not in Homoeoneuria/g1-Oligoneurisca).

(3) Penis has peculiar structure. Its dorsal walls of left and right lobes are movably connected proximally either by a single median condylus (Kluge 2004: Fig.48:A-B), or by a median sclerite forming a pair of articulations (Kluge 2004: Fig.49:F); in both cases penis lobes are able to protract backward turning apart. Unlike Oligoneuria/f4=g5 (which has similar articulation – see below), penis of Elassoneuria/g1 has no muscles-retractors.

(4) Larval head shield has a median longitudinal keel and a median angulate projection on anterior margin, lacks marginal setae [see Discoglossata (1)].

Plesiomorphies of Elassoneuria/fg1. Gonostylus is developed (unlike Homoeoneuria/g2 and Fittkauneuria), not less than with 2 distal segments (Kluge 2004: Fig.49:D-E) [see Discoglossata (12)] (unlike Oligoneuria/f4=g5). Larval and imaginal paracercus is well-developed (unlike Lachlania, Spaniophlebia and some Oligoneuriella/g2).