(Panephemeroptera Euephemeroptera Euplectoptera Anteritorna pm.Tridentiseta  
Tetramerotarsata Liberevenata Turbanoculata 
 pm.Protopatellata - Indocloeon/g1)

Nomen hierarchicum: Indocloeon/g1 [g:1982] (incl. Hindocloeon)

In circumscription fits:

— gen. Indocloeon Müller-Liebenau 1982: 125

References. Müller-Liebenau 1982: '; – Kluge 2012:361-376: *, *, *; – Kluge & Suttinun 2020 *, *, *

Autapomorphies of Indocloeon/g1.  

(1) Male genitals have peculiar structure (Kluge 2012: Fig.23–25, 27–29, 32, 33; Kluge & Suttinun 2020: Fig.46-49, 101–105): proximal (1st+2nd) segment of gonostylus is unusually short; distal (3rd) segment of gonostylus unusually long. In subimago distal segment is nearly as long as in imago, develops under larval cuticle without crumpling (Kluge 2012: Fig.35). In mature male larva subimaginal gonostyli developing under larval cuticle are folded as following: 2nd segment bent laterally; 3rd segment bent medially and curved anteriorly (Kluge 2012: Fig. 35). This mode of folding corresponds to the "Cloeon-type" which is usual for Protopatellata, but it looks unusual due to the fact that 2nd segment is very short and 3rd segment is very long, as in imago.

Other genital characters: Styligeral muscle is wide, paired, its left and right halves convergent toward styliger. Unistyligers are widely separated and very slightly projected distally. Penial bridge with wide rectangular median projection. Unlike most Protopatellata, gonovectes of penis are short, at most membranous.

Plesiomorphies and characters of Indocloeon/g1 of unclear phylogenetic status. 

(2) Larval head is narrow, with antennal bases brought together; frons between antennae forms a flat elevation, whose margins can somewhat overlap antennal bases (Kluge 2012: Fig.1) (see Index of characters [1.1.3]). 

(3) Left mandible has prostheca very massive; setae proximad of prostheca either present (in indonesiae [Indocloeon]) or absent (in primum [Indocloeon]); right mandible has prostheca stick-like, pressed to kinetodontium; proximad of prostheca a row of setae (see Index of characters [1.1.23], [1.1.24], [1.1.25]). Both mandibles have incisor and kinetodontium fused at most length; distalmost denticle of incisor turned ventrally and terminates far from apex (Kluge 2011: Fig.16, 17; Müller-Liebenau 1982: Fig.1h)

(4) Maxillary palp is indistinctly 3-segmented (Kluge 2011: Fig.5; Müller-Liebenau 1982: Fig.1e). Abiut their proportions see below, Indocloeon/g2 () and Hindocloeon (). About structure of maxilla see: Kluge & Suttinun 2020 and Fig.69.

(5) Labium has glossal and paraglossal muscles attached at one point near base of mentum (Kluge 2011: Fig.3) (see Index of characters [1.1.49]). About structure of glossae and paraglossae see: Kluge & Suttinun 2020 and Fig.7–9, 73–75.

(6) 2nd segment of labial palp has projected medio-apical angle (Kluge 2011: Fig.3; Müller-Liebenau 1982: Fig.1b-d). Muscle moving 3rd segment is retained. The same in some non-related taxa (see Index of characters [1.1.58]). Abiut shape of labial palp see below, Indocloeon/g2 () and Hindocloeon (). 

(7) Larval pronotum is short, without projected antero-lateral angles, with straight transverse ridge near anterior margin; mesonotum with hind margin projected between protoptera (Kluge 2012: Fig.4).

(8) Hind wings are absent. Larva has no vestiges of hind protoptera (Müller-Liebenau 1982: Fig.1f). Among Protopatellata hind wings are lost in Demoulinia, part of Rhithrocloeon/fg1 and part of Anafroptilum – see Index of characters [2.2.59].

(9) On middle and hind legs of subimago and imago tarsus is long, ½ of tibia length; proximal (1st+2nd) tarsal segment is long. Tibia is slightly longer than femur.

(10) On middle and hind legs of subimago and imago tarsus has one apical spine on 3rd tarsomere only, while 1st+2nd and 4th tarsomeres lack apical-ventral spines (Kluge 2012: Fig.19). On fore leg of female tarsus also has one apical spine on 3rd tarsomere only (Kluge 2012: Fig.20). The same in some other taxa (see Index of characters [], [2.2.83]).

(11) In subimago of both sexes all segments of all tarsi are covered with pointed microlepides. The same in many other Liberevenata other than Baetofemorata (see Index of characters [2.2.75], [], [2.2.83]).

(12) Larval legs are usually slender with femora parallel-sided (in spathasetis [Indocloeon] thicker), fore femur somewhat thicker and shorter than middle and hind femora; fore tibia somewhat shorter than middle and hind tibiae; fore tarsus somewhat longer than middle and hind tarsi (Kluge 2012: Fig.13, 14).

(13) Outer margin of larval femur lacks longitudinal row of stout setae; in profile view irregular short stout setae [see (15)] can be confused with such row (Kluge 2012: Fig.14). The same in some non-related taxa (see Index of characters [1.2.16]).

(14) Apex of each larval femur bears two stout blunt brown setae (Kluge 2012: Fig.15) [besides shorter stout setae on other parts of femur – see (15)]; on individual legs number of apical setae is greater than two (up to 8). The same in some non-related taxa (see Index of characters [1.2.15]).

(15) Larval femora [see (13), (14)], tibiae and tarsi have stout pointed bipectinate setae, which do not form regular rows; these bipectinate setae are most numerous on inner side of fore femur (Kluge 2012: Fig.13), less numerous on inner side of middle and hind femora.

(16) Larval claw is slender, slightly bent, with 2 rows of denticles [see Tetramerotarsata (11)], among which 3–4 distalmost denticles are larger and directed distally, and other denticles are very small (Kluge 2012: Fig.12; Müller-Liebenau 1982: Fig.1j) (see Index of characters [1.2.21]).

(17) Larval abdominal terga with scales in operculate sockets [see Turbanoculata (12)] (see Index of characters [1.3.4]).

(18) Both known species have larval cuticle of abdominal terga nearly unicolor, without contrasting markings or blanks; cuticle of abdominal sterna is nearly colorless.

(19) Tergalii are able to make rhythmical respiratory vibration (see Index of characters [1.3.30]), similar in both species: Tergalii I–VI with anal margin more convex than costal margin; tergalius VII with anal margin less convex than costal margin (Kluge 2012: Fig.9–11). Costal rib on tergalius I is short, on tergalii II–VII long, terminates near tergalius apex and bears denticles in apical part. Anal rib on tergalius I is absent, on tergalius II short, on next tergalii longer, on tergalius VII terminates near tergalius apex. All tergalii with tracheae dense and blackish.

(20) Larval cerci are long, paracercus twice shorter than cerci. At proximal half of cercus (equal to paracercus length) swimming setae [see (21)] are well developed; at distal half of cercus swimming setae absent. Paracercus bears swimming setae [see (21)] nearly up to its tip, only several very thin apical segments lack setation. 

(21) On larval caudalii [see (20)] each swimming seta is thick and pigmented in proximal half and thin and colorless in distal half (Kluge 2012: Fig.7) (see Index of characters [1.3.66]).

Plesiomorphies of Indocloeon/g1. 

In larva, subimago and imago of both sexes patella-tibial suture is present on middle and hind legs, absent on fore legs (Kluge 2012: Fig.13–15; Kluge & Suttinun 2020: Fig.13–14, 76–77) (unlike Anteropatellata) (see Index of characters [1.2.18], ibid. [], [2.2.82]).

Fore wings with no more than one marginal intercalary in each space (Kluge 2012: Fig.18, 37) (unlike Baetovectata) [see Liberevenata (2)] (Index of characters [2.2.55]). 

Lateral margins of all abdominal segments lack spines or denticles (unlike Cloeon/fg1 and Anafroptilum).

Size. Fore wing length 3.3–6 mm (see Tetramerotarsata). 

Distribution. Oriental Region.

The taxon Indocloeon/g1 is divided into:

1. Indocloeon/g2  

2. Hindocloeon