(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna Bidentiseta Furcatergaliae  
Ephemerella/fg1 - Ephemerella/fg2)

Nomen hierarchicum: Ephemerella/fg2 [f:1909; g:1862] (sine Tricorythus; incl. Timpanoga)

In circumscription fits:

— gen. Ephemerella: Eaton 1883–1888: 124

— subfam. Ephemerellinae: Allen 1965: 264

— fam. Ephemerellidae Klapalek 1909: 13

— Ephemerella/fg2: Kluge 2000: 252

References. Eaton 1883–1888: * *; – Needham & Traver & Hsu 1935: * *; – Edmunds & Jensen & Berner 1976: * *; – Studemann & Landolt 1997a: '; – McCafferty & Wang 2000: * *; – Kluge 2004: * * * *

Autapomorphies of Ephemerella/fg2.

(1) Tergalii II are lost. Thus, bilobed tergalii [see Ephemerella/fg1 (7)] are present either beginning from abdominal segment III (in Ephemerella/fg3) or from abdominal segment IV (in Timpanoga/fg1) (see Table).

(2) Tergalial ribs [non-marginal – see Furcatergaliae (5)] are lost (unlike Pantricorythi). Probably initial for Ephemerella/fg2 shape of dorsal lobe of tergalii III–VI [see Ephemerella/fg1 (7)] is truncate, with oblique or incised distal margin, with anal margin (directed medially) longer than costal margin (directed laterally); often dark colour pattern in a form of clover leaf is developed: "graft" arises from base of tergalius, and three "lives" are sided to costal margin (directed laterally), distal margin (directed posteriorly) and anal margin (directed medially) (Kluge 2004: Fig.91:A). These shape and colour pattern are occur in many (but not all) Ephemerella/fg2, being never found in other mayflies.

Character of Ephemerella/fg2 of unclear phylogenetic status.

(3) Fore wing with free marginal intercalaries (Kluge 2004: Fig.90:A). Non-unique character (see Index of characters [2.2.55]).

Plesiomorphies of Ephemerella/fg2. Unlike Pantricorythi: Transverse row of setae on larval fore femur [see Ephemerella/fg1 (12)] is usually irregular or lost; setae on outer margin of femur can be irregular, or form a regular longitudinal row not continued with the transverse row. 1st segment of gonostylus is not elongate, shorter than 1/2 of 2nd segment, sometimes completely fused with 2nd segment.

Unlike selected groups of Pantricorythi, imago and subimago is non-specialized: Eyes of male are always large, divided into two portions. Mesonotum with distinct mesonotal suture, curved lateroparapsidal suture and subimaginal lateral pigmented area bordered by relief line [see Ephemerella/fg1 (9) and (10)] (Kluge 2004: Fig.90:D). Cubital field of fore wing has up to 2 bifurcate veins arising from CuA (in largest species only); often the distal of these veins is vestigial (Kluge 2004: Fig.90:A: y). Hind wing is always well-developed, as long as 0.2–0.3 of fore wing length; at least RS with bifurcation; usually MP also has bifurcation; usually hind wing is oval, without prominent costal projection and with Sc terminating near apex (Kluge 2004: Fig.90:B); only in Teloganopsis and Hyrtanella/f2=Crinitella/g1 hind wing is modified. Imaginal wings without setae on hind margin.

Maxilla always with 2 dentisetae [see Bidentiseta (1)] and usually with 3 canines (only in Uracanthella and Cincticostella/g1 canines are modified or lost).

Size. Fore wing length 5–19 mm.

Distribution. Holarctic and Oriental Region.

The taxon Ephemerella/fg2 is divided into:

1. Timpanoga/fg1

2. Ephemerella/fg3