Chiridopsis tanganikana ( Spaeth, 1917 )

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 : 58-59

Chiridopsis tanganikana ( Spaeth, 1917)

( figs 16 , 22 , 96–99 )

Chirida tanganikana Spaeth, 1917: 440 .

Chiridopsis tanganyikana [sic]: Spaeth, 1924: 347.

Chiridopsis tanganikana: Spaeth, 1935: 176 ; Borowiec, 1999: 304.

Description. Le: 4.80–5.60 mm, Wi: 3.50–3.90 mm, Lp: 1.90–2.15 mm, Wp: 2.90–3.25 mm, Le/Wi: 1.34–1.47, Wp/Lp: 1.46–1.53. Body short-oval. Males slightly stouter than females.

Variable species. Pronotum yellow, disc with black spots ( figs 96, 98 ). In the most maculate form occur four spots: elongate spot in front of scutellum, round spot in area above head, and single round spot on each side of disc. Spot before scutellum tends to form V-shaped figure. In paler forms anterior spot obsolete, in extremely pale form occur only small two lateral spots. Scutellum yellow. Elytra yellow, disc with black pattern. In the darkest form sutural margin mostly black, along each side of suture run four elongate spots, along sides of disc run 7 more or less round spots (including spot on humerus and at base of elytral disc, additionally one spot occurs in anterior part of second interval. In aberrations number of sutural spots can be limited to two on each side of suture, occasionally all sutural spots obsolete. Lateral spots are less variable and at most the spot placed close to humeral spot can reduce but size of spots of the palest forms are twice smaller than size of spots of the darkest form. Spot on second interval always present but varies from large and round to small, elongate. Suture varies from partly black to completely yellow. Clypeus ( fig. 22 ) and thorax black, abdomen black with narrowly yellow sides. Legs yellow except for black trochanters. Antennae uniformly yellow or apex of last segment infuscate.

Pronotum regularly ellipsoidal ( figs 96, 98 ), with maximum width in the middle, sides broadly rounded, no basal corners. Surface of disc smooth and shiny. Explanate margin smooth and shiny, impunctate, with honeycomb structure.

Base of elytra wider than base of pronotum ( figs 96, 98 ), humeral angles distinctly protruding anterad, obtuse. Disc moderately, regularly convex in profile, without impressions ( figs 97, 99 ). Punctation fine, regular, moderately dense, distance between punctures in rows mostly as wide as to slightly narrower than puncture diameter. Punctures in rows gradually coarser from sutural to marginal rows, in submarginal row punctures approximately three times coarser than in sutural row. Intervals flat, several times wider than rows, marginal interval only slightly to 1.5 times wider than submarginal one. Surface of intervals smooth and shiny. Explanate margin narrow, strongly declivous, in the widest part 6.5–7.0 times narrower than disc, with well marked narrow marginal border. Surface of explanate margin distinctly shallowly punctate, interspaces shiny.

Clypeus 1.4 times as wide as long, almost flat ( fig. 22 ). Clypeal lines distinct, form regular central plate of triangular shape with obtuse top. Surface of clypeal plate microreticulate but shiny, with few small punctures. In some specimens at top of clypeal triangle runs medially short sulcus. Labrum shallowly emarginate to 1/5 length. Antennae moderately stout, segments 9–10 approximately as long as wide. Length ratio of antennal segments: 100: 50:53:63:53:50:57:60:63:60:126, segment 3 approximately 1.2 times as long as segment 2 and 0.8 times as long as segment 4.

Prosternal collar prominent, with prominent lateral angle. Prosternal process broad, moderately expanded apically, area between coxae flat, smooth and shiny with few small punctures, explanate apex flat, shiny with few small punctures.

Claws with small basal tooth, last segment of tarsi with distally projecting flanks thus claws appear distinctly dentate.

Distribution. Republic of Central Africa; Tanzania ( fig. 16 ).

Remarks. Chiridopsis tanganikana ( figs 96–99 ) belongs to the group of species with black pattern of numerous black spots on pronotal and elytral disc. Three species of the group have a pair of black spots behind the scutellum and one or two pairs of black spots close to suture: Ch. nigrostillata , Ch. tanganikana and Ch. tessellata ( figs 83, 84 , 96–101 ). Chiridopsis nigrostillata differs in presence of six black spots on pronotal disc and stouter body with length/width ratio 1.26, while in Ch. tanganikana and Ch. tessellata pronotal disc has only four spots and body is slimmer with length/width ratio 1.32–1.4. Ch. nigrostillata has row of five black spots along middle of elytron while in Ch. tanganikana and Ch. tessellata occur only two spots in anterior third of mid intervals. Chiridopsis tessellata differs in prosternal collar not angulate on sides while in Ch. tanganikana prosternal collar is distinctly angulate on sides.

Types examined. Syntype: [ TANZANIA] Dtsch. O. Afrika (MM); syntype: [ TANZANIA] Tanganika D. O. A. (MM)

Other specimen examined. REPUBLIC OF CENTRAL AFRICA: Bosum , 21–30 IV 1914, 1 ( DBET).

Figures

FIGURE 16. Distribution of Chiridopsis tanganikana.

FIGURES 20 – 23. Head. 20. Chiridopsis observabilis — species with flat clypeus; 21. Chiridopsis aubei — species with convex clypeus; 22. Chiridopsis tanganikana — species with long and angulate prosternal collar; 23. Chiridopsis tessellata – species with short and not angulate prosternal collar.

FIGURES 94 – 101. Chiridopsis picturata. 94. Dorsal, 95. Lateral, 96 – 99. Chiridopsis tanganikana. 96. Male dorsal, 97. Male lateral, 98. Female dorsal, 99. Female lateral; 100 – 101. Chiridopsis tessellata. 100. Dorsal, 101. Lateral.

FIGURES 80 – 86. Chiridopsis nigrosepta. Variation of dorsal pattern; 83 – 84. Chiridopsis nigrostillata. 83. Dorsal, 84. Lateral; 85 – 86. Chiridopsis klapperichi. 85. Dorsal, 86. Lateral.