Chiridopsis congoana (Spaeth, 1912)

Świ, Jolanta, 2017, A monograph of the Afrotropical Cassidinae (Coleoptera: Chrysomelidae). Part 4. Revision of the genus Chiridopsis Spaeth, Zootaxa 4316 (1), pp. 1-85 : 25-27

Chiridopsis congoana (Spaeth, 1912)

( figs 4 , 50–52 )

Chirida congoana Spaeth, 1912 a: 131, 1914: 126 .

Chiridopsis congoana Spaeth, 1924: 351 ; Borowiec, 1999: 299.

Description. Le: 6.9–7.6 mm, Wi: 6.1–6.5 mm, Lp: 2.5–2.7 mm, Wp: 4.2–4.5 mm, Le/Wi: 1.13–1.21, Wp/Lp ratio: 1.67–1.74. Body almost circular.

Pronotum yellow ( figs 50, 51 ), disc with large black spot usually of truncate anterior margin and marked with two very large triangular or semicircular yellow spots at base, often anterior margin black with narrow yellow median cleft. Scutellum black. Elytra yellow, suture narrowly black up to sutural apex, along marginal row runs a narrow black vitta surrounding apex and slightly enters surface of explanate margin of elytra, in humeral part the vitta strongly expanded to the surface of explanate margin and in extreme case extends to lateral margin of elytra but humeral angles always yellow, thin black lines run also along humeral callus and across middle of disc and on sides are connected with lateral vitta, in rare aberration transverse vitta absent. Thus, in typical aberration black pattern forms on disc black reticulation with four large yellow spots in anterior half, and two in posterior half of disc ( fig. 51 ). Head, ventrites, legs, and antennae usually yellow, sometimes apex of last segment infuscate, in some populations prosternum brown to black, metasternum brown to black with yellowish spot in the middle.

Pronotum elliptical ( figs 50, 51 ), with maximum width in the middle, anterior margin softly convex, sides broadly rounded, no basal corners. Surface of disc impunctate, shiny. Explanate margin broad, impunctate, shiny, transparent with well visible honeycomb structure.

Base of elytra much wider than base of pronotum, humeral angles distinctly protruding anterad, subrounded ( figs 50, 51 ). Disc unevenly convex in profile, slightly gibbous in postscutellar area, without impressions ( fig. 52 ). Punctation very fine, both on sides and top of disc, arranged in regular rows, but some rows create wavy lines, distance between punctures from two to five times wider than puncture diameter. Marginal row distinct, its punctures distinctly coarser than punctures in central rows. Intervals flat, five to six times wider than rows, only in posthumeral area narrower twice to thrice wider than rows, marginal interval in humeral area thrice wider than submarginal one, in posterior half slightly narrower than submarginal interval, no humeral or lateral folds.

Explanate margin broad, moderately declivous, in the widest part 4.5 times narrower than disc, surface impunctate, shiny, transparent with well visible honeycomb structure.

Eyes very large, gena obsolete. Clypeus broad, approximately 1.3 times as wide as long. Clypeal grooves fine but well marked, in basal half running close to margin of eyes then converging in obtuse angle, surface of clypeus regularly convex, shiny with few very small, setose punctures. Labrum minutely emarginate to 1/5 length. Antennae slim, segments 9–10 approximately 1.6 times as long as wide. Length ratio of antennal segments: 100:43:59:66:59:45:55:48:57:57:105. Segment 3 approximately 1.4 times as long as segment 2 and approximately 0.9 times as long as segment 4.

Prosternum broad in the middle, strongly expanded apically, area between coxa deeply impressed, surface with fine oblique wrinkles and several hairy punctures, expanded apex flat, with slightly irregular sculpture, and several hairy punctures.

Claws with moderate basal tooth each.

Distribution. Democratic Republic of Congo ( Zaire) ( fig. 4 ).

Remarks. Chiridopsis congoana ( figs 50, 51 ) belongs to the group of species with black stripes along sides of disc and black suture but differs from all such coloured species in explanate margin of elytra below humerus with black pattern. Specimens with thin black band across elytra are similar to Ch. opposita ( figs 87–89 ) and pale forms of Ch. nigrosepta ( figs 74–76 ) but both relatives differ in completely yellow explanate margin of elytra.

Types examined. 1 syntype: DEMOCRATIC REPUBLIC OF CONGO ( ZAIRE) Kabambare, Delhaise ( MRAC) ; 2 syntypes: DEMOCRATIC REPUBLIC OF CONGO ( ZAIRE) Kisantu, P. Goossens (1 MRAC, 1 MM) ; 1 syntype: DEMOCRATIC REPUBLIC OF CONGO ( ZAIRE) Manyema, Dupuis ( MRAC) .

Other specimens examined. DEMOCRATIC REPUBLIC OF CONGO ( ZAIRE): Albert Nat. Park, Ruwenzori, Mutawanga, 1000–1300 m, XI 1936 – II 1937, 1, II–III 1937, 2, Hackars (2 MRAC, 1 DBET) ; Albert Nat. Park , W Ruwenzori, 1200–1500 m, IV 1937, 1, Hackars ( DBET) ; Congo belge, 1 ( IRSN) ; Moero, Niunzu, 1 (MM); Tanganyika, Moero, Niunzu, 3, De Saeger (2 MRAC, 1 DBET).

Figures

FIGURE 4. Distribution of Chiridopsis circe (white circles), Chiridopsis congoana (black squares) and Chiridopsis tanzaniensis (black circles).

FIGURES 50 – 55. Chiridopsis congoana. 50. Female dorsal, 51. Male dorsal, 52. Male lateral; 53 – 55. Chiridopsis elongata. 53. Male dorsal, 54. Female dorsal, 55. Female lateral.

FIGURES 87 – 93. Chiridopsis opposita. 87. Male dorsal, 88. Female dorsal, 89. Female lateral; 90 – 91. Chiridopsis octoguttata. 90. Dorsal, 91. Lateral; 92 – 93. Chiridopsis subornata, black form. 92. Dorsal, 93. Lateral.

FIGURES 74 – 79. Chiridopsis nigrosepta. 74. Male dorsal, 75. Female dorsal, 76. Female lateral, 77 – 79. Variation of dorsal pattern (79. Form described as ab. vernicata).