Chiridopsis observabilis

Chiridopsis observabilis (Spaeth, 1916)

(figs 13, 20, 56–61)

Chirida observabilis Spaeth, 1916: 50.

Chiridopsis observabilis: Spaeth, 1924: 342; Borowiec, 1999: 301. Chiridopsis athinia Spaeth, 1924: 338, 343; Borowiec, 1999: 297, n. syn.

Description. Le: 4.55–5.20 mm, Wi: 3.65–4.05 mm, Lp: 1.70–1.90 mm, Wp: 2.65–2.95 mm; Le/Wi: 1.22–1.39, Wp/Lp: 1.55–1.63. Body short–oval to oval, males distinctly stouter than females (figs 56–61).

Dorsum uniformly yellow (figs 56–61). Head and thorax black, often central part of clypeal plate black but area between clypeal grooves and eye yellow to yellowish-brown (fig. 20), abdomen black, usually only last two sternites narrowly surrounded by yellow. Coxae black, trochanters brown to black, rest of legs yellow, sometimes extreme base of femora infuscate. Antennae uniformly yellow or last antennal segment partly infuscate.

Pronotum elliptical (figs 56, 57, 59, 60), with maximum width in the middle, anterior margin regularly convex, sides broadly rounded, no basal corners. Surface of disc impunctate or with extremely fine sparse pricks, shiny. Explanate margin broad, impunctate, shiny, transparent with well visible honeycomb structure.

Base of elytra much wider than base of pronotum (figs 56, 57, 59, 60), humeral angles distinctly protruding anterad, subangulate. Disc regularly convex in profile with top of convexity in postscutellar point (figs 58, 61), without impressions. Punctation fine, arranged in regular rows, from sparse to moderately dense, distance between punctures from as wide as to three times wider than puncture diameter. Marginal row distinct, its punctures distinctly coarser than punctures in central rows. Intervals flat, three to five times wider than rows, marginal interval 1.5–2.0 times wider than submarginal one, no humeral or lateral folds. Explanate margin narrow, strongly declivous, in the widest part five to six times narrower than disc, surface with very shallow, sparse punctures or impunctate, appears regular, shiny, transparent with well visible honeycomb structure.

Eyes very large, gena obsolete (fig. 20). Clypeus broad, 1.4–1.5 times as wide as long. Clypeal grooves deep, converging in regular triangle, surface of clypeus slightly to moderately convex, microreticulate but shiny with several very small, setose punctures. Labrum minutely emarginate to 1/7 length. Antennae moderately slim, segments 9–10 approximately 1.1 times as long as wide. Length ratio of antennal segments: 100:50:69:69:56:44:56:56:59:63:119. Segment 3 approximately 1.4 times as long as segment 2 and approximately as long as segment 4.

Prosternum broad in the middle, strongly expanded apically, area between coxae flat but usually with thin median groove, surface without special sculpture, shiny, with few small punctures, expanded apex flat, with regular surface and several very small punctures.

Claws with moderate basal tooth, apical flanks of last segment of tarsi expanded, dentiform.

Distribution. E Republic of Congo (Zaire), Ruanda, and Kenya (fig. 13).

Remarks. We have examined types of both Chirida observabilis (figs 56–58) and Chiridopsis athinia (figs 59–61) and did not find any differences, thus we treated Ch. athinia as junior synonym of Ch. observabilis.

Chiridopsis observabilis with Ch. flavipennis and completely yellow aberration of Ch. aubei (ab. baumanni) form a group of very similar species with brown to black clypeus and short-oval to subcircular body (figs 39, 111, 112). Identification of these three forms requires comparison with series of properly identified specimens. In Ch. aubei clypeal grooves run close to the margin to eyes and on top of clypeal triangle converging in obtuse angle (fig. 21) while in Ch. flavipennis and Ch. observabilis clypeal grooves form regular triangle with sharp top thus between the triangle and inner margin of eyes runs a well visible, convex fold often paler coloured than clypeal triangle (fig. 20). Of these three similar forms Ch. observabilis has almost flat clypeus, while it is moderately convex in Ch. flavipennis and strongly convex in Ch. aubei ab. baumanni. These taxa need genetic studies, perhaps they represent only infraspecific variability of a widely spread taxon, or they are cryptic species with some microhabitat preferences. Lectotype of Chrida observabilis Spaeth, 1916 has been designated to avoid confusion with other taxa of uniformly yellow pronotum and elytra.

Types examined. Lectotype of Chirida observabilis (present designation): [DEMOCRATIC REPUBLIC OF CONGO (ZAIRE)] NW Tanganika S., 1800–2000 m, Grauer (NMW); paralectotype of Chirida observabilis (present designation): the same data (MM).

Lectotype and 3 paralectotypes of Chiridopsis athinia (designated by Borowiec 1999: 297): [KENYA] Bassin de l’Athi, Kikouyou, Riv. Kamiti, X 1909, Alluaud (MNHN); 2 paralectotypes of Chiridopsis athinia (designated by Borowiec 1999: 297): [KENYA] Nairobi, Wa-Kikouyou et Masai, 1904, Alluaud (MNHN); 3 paralectotypes of Chiridopsis athinia (designated by Borowiec 1999: 297): [KENYA] Nyère, SO Praries, 2000 m, 1909, Ch. Alluaud (MM); paralectotype of Chiridopsis athinia (designated by Borowiec 1999: 297): [KENYA] NO Praries, 2000 m, 1909, Alluaud (MNHN).

Other specimens examined. DEMOCRATIC REPUBLIC OF CONGO (ZAIRE): Albert Nat. Park, Lake Edouard, Kamande, 925 m, 8 IV 1936, 1 (DBET).

KENYA: Athi Plains, 1 (DBET); Nairobi, Hotel Boulevard, 1600 m, 8 I 1976, 1, N. Møller Andersen (DBET).

RUANDA: Rubona, V 1963, 1 (DBET).