(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna Bidentiseta Branchitergaliae
Heptagennota Pentamerotarsata Radulapalpata 
Epeorus/fg1Rhithrogena/fg2CinygmulaRhithrogena/fg3 - Epeiron/g1)

Nomen hierarchicum: Epeiron/g1 [g:1964] (incl. Tumungula)

In circumscription fits:

— Epeiron/g(1): Kluge 2004: 195

Reference. Kluge 2004: * * *

Autapomorphies of Epeiron/g1.

(1) Tergalii [sucking, with costal ribs located far from costal margin – see Rhithrogena/fg3 (3)] have peculiar shape: tergalii II–VI are short, with costal rib strongly curved; at least tergalius VI has incised posterior-distal margin (this is the margin, by which it overlaps anterior margin of tergalius VII) (Kluge 1987b: Fig.15–22).

Character of Epeiron/g1 of unclear phylogenetic status. 

(2) In imago and subimago 1st segment of fore tarsus is relatively long, subequal or equal to 2nd segment, rarely longer. Among Rhithrogena/fg3 the same in Himalogena, unlike Rhithrogena/fg4 and Sibirigena; the same in many other mayflies.

(3) Penis without titillators (unlike Rhithrogena/fg4, Himalogena and part of Sibirigena).

Size. Fore wing length 5–10 mm.

Distribution. Asia: from Asia Minor to Indo-China.

The taxon Epeiron/g1 is divided into:

1. Epeiron/g2

2. Tumungula