(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna pm.Tridentiseta  
Tetramerotarsata Liberevenata Turbanoculata 
 pm.Protopatellata - Rhithrocloeon/fg1)

Nomen hierarchicum: Rhithrocloeon/fg1 [f:2012; g:1985] (incl. Thraulobaetodes)

In circumscription fits:

— Rhithrocloeon/fg1: Kluge 2015

— Rhithrocloeoninae: Kluge 2015

References. Kluge 2015:

Autapomorphies of Rhithrocloeon/fg1.

(1) Male gonostyli [see Liberevenata (5)] are non-arched, «ankylosed» [see (1.a)]; larval protogonostyli are brought together [see (1.b)].

(1.a) Imaginal gonostyli. In contrast to all other Baetidae and most other Ephemeroptera, whose gonostyli are arched in such a manner that their apices are directed medially to meet one another, gonostyli of Rhithrocloeoninae are not arched: 1st segments of gonostylus (immovably fused with 2nd) is strongly projected medially-ventrally; 2nd segment is not arched, but nearly straight or even somewhat bent in opposite direction (Kluge 2012: Fig.42). 3rd segment of gonostylus is either diminished, or lost: it is diminished in Thraulobaetodes (Kluge 2015: Fig.36-37, 39-41) and completely lost in Rhithrocloeon/fg2 (Kluge 2012: Fig.12-18, 20, 31, 40-42, 45; Kluge 2015: Fig. 61) [see below, Rhithrocloeon/fg2 (1)] (in all other Liberevenata distal segment of gonostylus is retained).

(1.b) Larval protogonostyli. (Kluge 2012: Fig.1, 46) Male larva has protogonostyli brought together (unlike other Turbanoculata, whose protogonostyi are widely separated); in mature larva buds of subimaginal gonostyli, developed under larval cuticle, are entirely convergent, so that their apices are brought together. This character is known for Thraulobaetodes (Kluge 2015: Fig.35), three examined species of Kivuiops (Kluge 2012: Fig.1) and for Bugilliesia/g(1) sudanense [Centroptilum] (Kluge 2012: Fig.46). Unlike Rhithrocloeon/fg1, in all other Protopatellata, as well as in Anteropatellata-non-Baetovectata, buds of 2nd segments of subimaginal gonostyli are divergent (see Index of characters [2.3.9]).

(2) Maxillary palp has 3rd segment very small, narrower than 2nd segment. In Rhithrocloeon/fg2 2nd segment is widened and flattened toward apex, 3rd segment is short and triangular, separated from 2nd segment by oblique suture (Kluge 2012: Fig.27-28). In Thraulobaetodes 2nd segment is not widened, 3rd segment is very small or absent (individual variability) (Kluge 2015: Fig.5-6, Fig.8). 

Characters of Rhithrocloeon/fg1 of unclear phylogenetic status.

(3) Tergalii able to rhythmic respiratory movements (see Index of characters [1.3.30]). This was observed by me for Thraulobaetodes, all examined species of Kivuiops/g(1) and reported by Gillies (1997) for one species of Bugilliesia/g(1) – griseum [Afroptilum]. Judging by the same paper (Gillies 1997: Table 1), Rhithrocloeon/fg3 has immobile tergalii; but this conclusion was based on observation of a single individual of Rhithrocloeon sp., and can be an error. Tergalii of all seven pairs are simple and oval, with costal and anal ribs developed.

(4) Hind wings, if present, of «Centroptilum-type»: narrow, with two longitudinal veins, with simple (not bipointed) hooked costal process  (Kluge 2012: Fig.43; Kluge 2015: Fig.31-32) (see Index of characters [2.2.60]). Hind wings are retained in Thraulobaetodes and plesiomorphon Bugilliesia, vestigial in Mutelocloeon, absent in Rhithrocloeon/fg3 and Adnoptilum.

(5) In subimago of both sexes, all segments of all tarsi are covered by pointed microlepides. This is true for species examined. The same in all other examined Protopatellata, and Anteropatellata-non-Baetovectata, unlike some Baetovectata, which have blunt microlepides (see Index of characters [2.2.75], [], [2.2.83]).

(6) Gonovectes are completely fused with penial bridge; gonoducts open at the middle of the integral penis. In other respects penis structure is variable: in some species it retains a form of integral sclerotized bridge, movably articulated with latero-apical angles of abdominal segment IX (Kluge 2012: Fig.12-18, 31, 45; Kluge 2015: Fig.37); in some species it is partly fused with protogonostyli to form a composite construction (Kluge 2012: Fig.40-42). Complete fusion of gonovectes with penial bridge, besides Rhithrocloeon/fg1, independently occurs in Anteropatellata-Cloeon/fg1 (see Index of characters [2.3.16a]).

Plesiomorphies of Rhithrocloeon/fg1. In all stages of both sexes patella-tibial suture is present on middle and hind legs, being absent on fore leg [see Protopatellata (1)]. Fore wing with no more than one marginal intercalary in each space (Kluge 2012: Fig.21; Kluge 2015: Fig31) (unlike Baetovectata).

Size. Fore wing length 3–12 mm (see Tetramerotarsata). 

Distribution. Afrotropical Region.

The taxon Rhithrocloeon/fg1 is divided into:

1. Thraulobaetodes

2. Rhihrocloeon/fg2

2.1. Plesiomorphon Bugilliesia

2.2. Rhithrocloeon/fg3

2.2.1. Rhithrocloeon/fg4

2.2.2. Kivuiops

2.3. Mutelocloeon

2.4. Adnoptilum  

Some taxa are known as imagoes only and have uncertain systematic position

See also:

Turbanoculata INCERTAE SEDIS