Potamocloeon dentatum ( Kimmins 1956 )

Kluge, Nikita J., 2019, Potamocloeon edentatum sp. n. from Usambara Mountains in Tanzania (Ephemeroptera, Baetidae), Zootaxa 4648 (2), pp. 299-317 : 302-304

Potamocloeon dentatum ( Kimmins 1956)

( Figs 1–12 )

Cloeon dentatum Kimmins 1956: 76 (♂ imago and ♂ subimago; Jinja in Uganda); Kimmins 1960: 340 (new record of imago; Jinja); Tjønneland 1960 (flight activity; Jinja); Kimmins 1971: 312; (holotype in British Museum); Gillies 1980: 148 (♀ imago; Ivory Coast); Gillies 1985: 9 (imago); Gillies 1988: 52 (imago, non larva). Potamocloeon dentatum: Gillies 1990b: 207 (imago, non larva). Afroptilum plumosum Wuillot in Wuillot & Gillies 1993: 276 (larva and reared ♂ imago; Mali) (synonymized with dentatum [ Cloeon ] by Jacobus et al. 2006). Maliqua plumosa: Lugo-Ortiz & McCafferty 1997: 368 (larva and ♂ imago).

Cloeodes dentatu s: Jacobus, McCafferty & Gattolliat 2006: 132 (= Maliqua plumosa ).

Potamocloeon (Potamocloeon) dentatum: Salles, Gattolliat & Sartori 2016: 108 .

Material examined. MALI, Bafing bei Tinko 1–9.X.1991 and 2.IX.1992, coll. D. Tobias: 3 I ♂, 3 S ♂, 4 I ♀, 5 S ♀. UGANDA, Jinja , 6–10. VII.2997, coll. N. Kluge, 1 I ♂, 1 S ♂.

Larva. Described by Wuillot & Gillies (1993) as Afroptilum plumosum .

Subimago. CUTICULAR COLORATION. Pronotum colorless. Mesonotum at most part light brownish; most sutures darker brown; colorless stripe along anterior part of medioparapsidal suture ( Fig. 6 ). Thoracic pleura and sterna with colorless and brown areas. Wing colorless with brown microtrichia. Legs colorless, microtrichia and tarsal microlepides light brownish. Abdomen and gonostyli colorless with brownish microtrichia. Cerci colorless with setae brown.

TEXTURE. On legs of all pairs of both sexes, all tarsal segments covered by pointed microlepides, only small basal part of fore segment covered by microtrichia (as tibia and other leg segments).

Imago, male ( Figs 1–3 ). Head ocher with brown. Turbinate eyes brown. Thorax brown, uniformly colored dorsally, laterally and ventrally. Fore wing with one marginal intercalary per space; pterostigma with 3–5 simple, oblique, complete or/and incomplete veins (Wuillot & Gillies 1993: fig. 39); bases of wings brownish, remainder colorless; veins, including costal brace, colorless. Hind wings absent. Legs of all pairs either uniformly ocher ( Fig. 5 ), or middle and hind femora with faint reddish band distally. Middle and hind legs with tibia equal or slightly longer than tarsus; first tarsomere (primary 1st+2nd) much longer than others; one terminal spine on 2nd (primary 3rd) tarsomere ( Fig. 5 ). Abdominal segments I–VII whitish; terga and sterna with more or less expressed unpaired gray median spot on each joining of segments; terga with or without paired diffusive pale reddish markings; lateral trachea with blackish. Segments VIII–IX with terga brown or reddish, sterna whitish, anteriorly bordered by brown; segment X brown. Unistyligers and gonostyli light ocher. Cerci uniformly whitish.

Male genitals ( Figs 7–12 ). Sterno-styligeral muscle very wide, proximally much wider than distance between median paraproctal muscles, distally wider than distance between unistyligers. In imago ( Figs 7–10 , 12 ), unistyliger with stretched inner-apical margin; first segment of gonostylus of composite shape, with narrowing near midlength, with inner-distal angle acute and projected distally; second segment of gonostylus nearly straight, basally narrowed; third (apical) segment of gonostylus petiolate, triangular; external part of penis semicircular; penial arms short and thick, with apices bent distally and free (not fused with penial bridge). Subimaginal gonostylus with sharply projected inner-apical angle of 1st segment ( Fig. 11 ).

Dimension. Fore wing length 3.5–4.5 mm.

Discussion. When Gillies accepted dentatum [ Cloeon ] as the member of the genus Cloeon , he stated that its adult differs from other species of Cloeon in longer vein MA2, which reaches «up to or almost to the cross-vein between MA1 and MP 1» ( Gillies 1980: 148, fig. 6; Gillies 1988: 52). Among two specimens collected by me in Jinja (the type locality), one (male subimago) has such long MA2, while another (male imago) has MA2 much shorter, far not reaching this cross vein. The same variability is found among male imagines and subimagines from Mali.

Figures

FIGURES 1–10. Potamocloeon dentatum. 1, head and thorax of male imago from Uganda; 2, its abdominal sterna and terga; 3, abdominal sterna and terga of male imago from Mali; 4, abdominal sterna and terga of male subimago from Uganda; 5, hind leg of male imago; 6, subimaginal mesonotum; 7–10, genitals: 7, holotype; 8–9, specimens from Mali; 10, specimen from Uganda.

FIGURES 11–13. 11–12, Potamocloeon dentatum: 11, genitals of subimago; 12, genitals of imago (styligeral and gonostylar muscles shown only on left side, gonoduct shown by dotted line). 13, Potamocloeon edentatum sp. n., fore wing (holotype). Abbreviations: gd – gonoduct; gs1–gs3, segments of gonostylus; m.IX-X, areas of anterior attachment of median paraproctal muscles (i.e., muscles going from sternum IX to common base of paraprocts); m.sg, median sterno-styligeral muscle.