Mutelocloeon Gillies & Elouard 1990

Kluge, Nikita J., 2015, First description of winged stages of Thraulobaetodes Elouard & Hideux 1991 and reclassification of Rhithrocloeoninae (Ephemeroptera, Baetidae), Zootaxa 3949 (4), pp. 491-514 : 508-511

Mutelocloeon Gillies & Elouard 1990

( Figs 56–64 )

Rank-free hierarchical name: Mutelocloeon /g(1).

Type species: Mutelocloeon bihoumi Gillies & Elouard 1990 . References: Gillies & Elouard 1990: imago, larva.

Composition. Two species are described: corbeti Kimmins 1956 [ Centroptilum ] is known as imagoes from Uganda and bihoumi Gillies & Elouard 1990 [ Mutelocloeon ] is described as imagoes and larvae from Guinea (imagoes were not reared, and their association with larvae is based on hypodermal coloration).

Material examined. Mutelocloeon corbeti : ZAMBIA, River Zambezi above Victoria Falls, 29–30.VIII.2014, coll. N. Kluge & L. Sheyko: 2 S-I♂, 1 S♂, 1 S♀.

Characters of larva. Larva (known for M. bihoumi only) is adapted for inhabitance in mantle cavity of mussels and has highly derived structure ( Gillies & Elouard 1990).

Characters of imago. Hind wings are reduced to a small processes (in contrast to being well developed in Bugilliesia and completely lost in Rhithrocloeon ). Other characters are described by Kimmins (1956) and Gillies & Elouard (1990).

Additional characters of imago (based on M. corbeti ). Patella-tibial suture absent on all legs. All tarsal segments without apical thorns. Genitals of male entirely colorless; middle part of penial bridge (visible between unistyligers) sclerotized, convex, bent ventrally ( Fig. 61 ) has characteristic shape in ventral view ( Figs 62 ).

Characters of subimago (based on M. corbeti ). CUTICULAR COLORATION. Head and prothorax colorless. Mesonotum at most colorless, with certain sutures contrastingly dark brown ( Fig. 63 ). Meso- and metapleura colorless with some sclerites brown; posterior part of postsubalar sclerite with concave dorsal margin ( Fig. 64 ). Thoracic sterna, legs, abdomen and caudalii colorless.

HYPODERMAL COLORATION: Similar to imago.

TEXTURE: On all legs of male and female all tarsal segments covered with sparse small pointed microlepides.

Egg structure (based on M. corbeti ) ( Figs 56–59 ).Oval, 0.13–0.15 mm length; chorion with characteristic relief in form of round impressions, partly connected, partly separated by partitions with flat surfaces. The same in Bugilliesia (see above).

Figures

FIGURES 56 – 60. Mutelocloeon bihoumi. 55 – 59, eggs (extracted from female imago); 60, male imago.

FIGURES 61 – 64. Mutelocloeon bihoumi. 61, genitals of male imago (at left half, ventral view; at right half, dorsal view, gonostylar muscle not shown). 62, the same, median section (external surfaces dotted); 63, 64, subimaginal exuviae spread on slide (on the same scale): 63, right half of mesonotum; 64, subalar sclerite of mesothorax. Abbreviations: gd, gonoduct; gs 1, gs 2, segments of gonostylus; m. IX-X, paired intersegmental muscle going from abdominal sternum IX to common base of paraprocts; m. gs, gonostylar muscle; m. gv 1, m. gv 2, muscles of gonovectis; m. s, sterno-styligeral muscle; us, unistyliger.