(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna Bidentiseta Furcatergaliae  
Leptophlebia/fg1 Atalophleboadentata Atalophlebopectinata Atalophleboculata Atalophlebomaxillata Atalophlebolinguata 
... Choroterpes/fg1)

Nomen hierarchicum: Choroterpes/fg1 [f:2012; g:1881] (incl. Thraulus, Nonnullidens)

In circumscription fits:

— Choroterpes/fg1 = tribus Choroterpini Kluge 2012:229-262

References. Kluge 2012:229-262:

Autapomorphies of Choroterpes/fg1.

(1) Difference between tergalius I and tergalii II–VII is more or less expressed: tergalius I tends to narrowing and simplification, while tergalii II–VII usually retain both lamellae, which are widened and have additional processes (in Choroterpes/fg2 each lamella has up to three processes, in Thraulus/g1 – many processes).

In Choroterpes/fg2 and Sangpradubina the first tergalius is usually unilamellate, very narrow, thread-like, with a single non-branched trachea (Kluge 2012: Fig.6, 30, 57, 76, 98, 120); rarely wider, with trachea branched (in nigrescens [Choroterpes]); rarely with one process (in Neochoroterpes/g(1) — Kluge 2012: Fig.66); rarely bilamellate, with both lamellae slender and lacking processes (in petersi [Choroterpes]). Sometimes the first tergalius undergoes further reduction: in prati [Choroterpes] it is present in male, absent in female; in Dilatognathus it is completely lost.

In Thraulus/g1 the first tergalius usually has both lamellae slender and lacking processes; rarely consists of a single slender lamella lacking processes (in femoratus [Thraulus]). 

In Nonnullidens the first tergalius can be bilamellate and similar to tergalii II–VII (Kluge 2013: Fig.4-6, 32-34); but unlike tergalii II–VII, tergalii I are always immovably directed backward and do not make respiratory movements..

Characters of Choroterpes/fg1 of unclear phylogenetic status. 

(2) Larval patella-tibial suture is lost on all legs (Kluge 2012: Fig.24–27, 46–48, 85–87, 147–149; 2013: Fig.29-31). In contrast to larva, in imago and subimago patella-tibial suture usually retains the primitive condition, being present on middle and hind legs and absent on fore legs (see Index of characters [1.2.18], ibid. [2.2.82]); among species examined, only in oklahoma [Choroterpes] imago and subimago lack patella-tibial suture on all legs, as in larva. The same in Indialis.

(3) Hind wing has Sc terminating near middle of costal margin; costal projection is expressed and varies from short and obtuse (Kluge 2012: Fig.16, 88, 106, 135–137) to stretched and pointed (Kluge 2012: Fig.40, 50; Kluge 2013: Fig.16, 38, 48) (see Index of character [2.2.62]). Larval hind protopteron in all cases has obtuse costal projection; if adult costal projection is stretched and pointed, it grows when wing develops from protopteron (Kluge 2012: Fig.51,52; Kluge 2013: Fig.27, 37, 47).

Plesiomorphies of Choroterpes/fg1.

(4) Imaginal and subimaginal claws of all legs are ephemeropteroid (see Index of characters [2.2.85]).

Size. Fore wing length 4–9 mm.

Distribution. Mainly Arctogea (Afrotropical, Oriental, Palaearctic and Nearctic Regions) with a few species in the north of Neotropical Region (see Choroterpes/fg2).

The taxon Choroterpes/fg1 is divided into:

1. Choroterpes/fg2

1.1 Choroterpes/fg3

1.1.1 Plesiomorphon Choroterpes/fg4

1.1.2 Neochoroterpes

1.2 Euthraulus/g1

1.2.1 Plesiomorphon Euthraulus/g2

1.2.2 Monochoroterpes

1.2.3 Dilatognathus

2. Thraulis/fg1

3. Nonnullidens/g1 (inc. Barba)

4. Sangpradubina/g(1)