Indocloeon Müller-Liebenau 1982

Kluge, Nikita J. & Suttinun, Chanaporn, 2020, Review of the Oriental genus Indocloeon Müller-Liebenau 1982 (Ephemeroptera: Baetidae) with descriptions of two new species, Zootaxa 4779 (4), pp. 451-484 : 455

Subgenus Indocloeon Müller-Liebenau 1982 , s. str.

Hierarchical name: Indocloeon /g2.

( Figs 1–55 )

Type species: Indocloeon primum Müller-Liebenau 1982 .

Diagnosis. Larva. (1) Labrum with 2 paired setae between submedian setae and submarginal arc of setae ( Fig. 6 ; Müller-Liebenau 1982: fig. 1a). (2) Incisors of left and right mandibles terminated by 3 denticles, 2nd denticle longest ( Figs 1–2 ; Müller-Liebenau 1982: fig. 1h). (3) Left mandible without setae proximad of prostheca ( Fig. 1 ; Müller-Liebenau 1982: fig. 1h). (4) Mola of left mandible with seta(e) on proximal angle (as well as on right mandible) ( Fig. 1 ; Müller-Liebenau 1982: fig. 1h). (5) Maxillary palp consists of 2 subequally long segments and a very short 3rd segment ( Fig. 5 ; Müller-Liebenau 1982: fig. 1e). (6) Paraglossae gradually narrowed from base to apex ( Figs 3–4 ); dorso-median setal row consists of 2 (occasionally 3) stout setae ( Fig. 8 ; Müller-Liebenau 1982: fig. 1b). (7) Labial palp with sharp point on apico-median projection of 2nd segment ( Figs 3, 4 , 7 ; Müller-Liebenau 1982: fig. 1b–c); exuviae of this segment often crumpled longitudinally, but with point retaining its shape. (8) Tibiae of middle and hind legs have the same setation as tibia of fore leg: with one stout outer-apical seta (occasionally 2 or more such setae), without other stout setae on outer margin ( Fig. 14 ).

Imago and subimago. (9) Antenna: scapus without hypodermal pigmented spots; proximal part of pedicellus with hypodermal pigmented spots on lateral and median sides ( Fig. 35 ). (10) First abdominal segment without lateral spots ventrad of metathoracic postnotum ( Figs 41 , 45 ). (11) Each abdominal tergum II–VI with transverse brown or reddish stripe on posterior margin ( Figs 36–39 , 41–45 ).

Subimaginal cuticle. (12) Postsubalar sclerite with postero-dorsal angle stretched to a long projection ( Kluge 2012: fig. 34).

Genitals of male imago. (13) Styliger with sharply outlined median impression ( Fig. 46 ; Kluge 2012: fig. 32). (14) Gonovectes without movably articulated distal portions ( Fig. 46 ; Kluge 2012: fig. 32).

Egg. (15) One polar area (about ¼ of egg length) with net-like relief; remainder of surface with sharply outlined cavities ( Figs 50–55 ).

Composition and distribution. Two species: Indocloeon (Indocloeon) primum Müller-Liebenau 1982 and Indocloeon (Indocloeon) secundum sp. n.; both species in Sri Lanka only.

Figures

FIGURES 1–5. Larvae of Indocloeon s. str. 1–3, Indocloeon (Indocloeon) secundum sp. n.: 1–2, left and right mandibles of holotype (arrow shows seta on proximal angle of left mola); 3, labium (focus on ventral side); 4–5, Indocloeon (Indocloeon) primum, labium and maxilla (focus on ventral side).

FIGURES 6–9. Larvae of Indocloeon (Indocloeon) secundum sp. n. 6, labrum (arc, submarginal arc of setae; s1, s2, setae between submedian seta and submarginal arc; s-med, submedian seta); 7, labial palp, dorsal view; 8, paraglossa, dorsal view (d-m, dorso-median row of setae); 9, paraglossa and glossa, ventral view (v-m, ventro-median row of setae) (6, 8–9, holotype).

FIGURES 10–14. Larva of Indocloeon (Indocloeon) secundum sp. n. (holotype). 10–11, claw; 12, two outer-apical setae on fore tibia; 13, tibia of fore leg; 14, tibia of middle leg.

FIGURES 15–24. Larva of Indocloeon (Indocloeon) primum. 15–20, posterior margins of abdominal terga I, II, IV, VII, IX and X (black triangle shows median line on tergum IX); 21, abdominal tergum VI; 22, abdominal sternum III; 23, cercus; 24, scales on abdominal sternum, enlarged.

FIGURES 25–34. Larvae of Indocloeon (Indocloeon) secundum sp. n. 25–30, posterior margins of abdominal terga I, II, III, VII, IX and X (black triangle shows median line on tergum IX); 31, abdominal tergum VI; 32, abdominal sternum V; 33, cercus; 34, scales on abdominal sternum, enlarged (25–30, 33, holotype).

FIGURES 35–39. Imagines of Indocloeon (Indocloeon) primum. 35, antennae of female imago; 36, abdominal terga and sterna of male imago (genitals removed); 37, male imago; 38, abdominal terga and sterna of female imago; 39, female imago.

FIGURES 40–41. Indocloeon (Indocloeon) secundum sp. n. (holotype). 40, larval paraprocts; 41, male imago.

FIGURES 42–45. Indocloeon (Indocloeon) secundum sp. n., female imagines.

FIGURES 46–49. Male genitals of Indocloeon s. str. 46, imaginal genitals of Indocloeon (Indocloeon) secundum sp. n. (holotype) (1+2, proximal segment of gonostylus; 3, distal segment of gonostylus; m.d, dorsal muscle of penis; m.gs, gonostylar muscle; m.gv, gonovectal muscle; m.s., median sterno-styligeral muscle); 47, their subimaginal exuviae; 48, gonostylus of Indocloeon (Indocloeon) primum; 49, its subimaginal exuviae.

FIGURES 50–52. Egg of Indocloeon (Indocloeon) primum. 50, general view; 51–52, enlarged areas marked by frames on Fig. 50.

FIGURES 53–55. Egg of Indocloeon (Indocloeon) secundum sp. n. 53, general view; 54–55, enlarged areas marked by frames on Fig. 53.