Cassida camerunensis ( Spaeth, 1903 )

Borowiec, Lech & Świętojańska, Jolanta, 2022, A monograph of the Afrotropical Cassidinae (Coleoptera: Chrysomelidae). Part 6. Revision of the tribe Cassidini 3, the genus Cassida L., Zootaxa 5171 (1), pp. 1-250 : 41-42

Cassida camerunensis ( Spaeth, 1903)

( figs. 7 , 95–96)

Coptocycla (?) camerunensis Spaeth, 1903: 178, 1914 b: 131 .

Cassida camerunensis: Borowiec, 1999: 241 .

Description. L: 4.95–5.70 mm, W: 4.30–4.90 mm, Lp: 1.80–2.00 mm, Wp: 3.45–3.70 mm, L/W: 1.15–1.18, Wp/ Lp: 1.85–1.95. Body almost circular (fig. 95).

Pronotum and scutellum ochraceous yellow. Elytral disc ochraceous yellow with black pattern: a stripe on suture behind scutellum, numerous spots around disc forming more or less distinct U–shaped figure and few longitudinal spots on second and fourth intervals. The black markings are mixed with ground colour and only in the darkest aberrations form solid large black bands in posthumeral area and in posterolateral parts of disc. Explanate margin ochraceous yellow with broad humeral spots at least partly extending to the anterior margin of elytra but never extending to the lateral margin of elytra (figs. 95, 96). Head yellow, prosternum from yellow to mostly infuscate, metasternum from mostly brown to black, usually with paler posterolateral corners and lateral plates, abdomen from mostly ochraceous yellow with only central part infuscate to mostly black surrounded by ochraceous yellow. Legs ochraceous yellow. Antennal ochraceous yellow, at most last segment infuscate apically.

Pronotum regularly elliptical, with maximum width in the middle, anterior margin regularly convex, sides broadly rounded, no basal corners. Area above head only slightly impressed, lateral lobes marked but indistinctly bordered from explanate margin. Surface of disc alutaceous, with fine and very shallow but dense punctation. Explanate margin broad, impunctate, alutaceous, transparent with well visible honeycomb structure.

Base of elytra much wider than base of pronotum, humeral angles distinctly protruding anterad, angulate. Disc regularly convex in profile (fig. 96), with shallow postscutellar and principal impressions and hardly marked H–shaped postscutellar elevation. Punctation coarse, arranged in completely regular rows, postscutellar impressions often with additional irregular punctures. Punctures in rows dense, distance between punctures mostly narrower than puncture diameter. Marginal row distinct, its punctures not or only slightly coarser than punctures in central rows. Intervals mostly flat but second interval on slope with short longitudinal elevation and fourth interval in the middle slightly convex, in sutural area intervals as wide as rows on sides narrower than rows to linear, marginal interval broad, twice wider than lateral intervals, without humeral folds but with short lateral fold. Explanate margin broad, moderately declivous, in the widest part three times narrower than disc, surface from slightly alutaceous to slightly shiny with indistinct very sparse punctation, appears regular, transparent with well visible honeycomb structure, only black humeral spots with coarse, shallow punctures.

Eyes very large, gena obsolete. Clypeus moderately broad, approximately 1.1 times as wide as long. Clypeal grooves fine but well marked, converging in triangle with obtuse top, surface of clypeus flat, its surface shiny with few small punctures. Labrum minutely emarginate to 1/6 length. Antennae slim, segments 9–10 approximately 1.5 times as long as wide. Length ratio of antennal segments: 100:53:63:61:53:50:61:47:55:50:111. Segment 3 approximately 1.2 times as long as segment 2 and only slightly longer than segment 4.

Prosternum moderately broad in the middle, strongly expanded apically, area between coxa flat with few moderately coarse punctures, shiny, expanded apex without special sculpture except several few moderately coarse, setose punctures.

Claws with large basal tooth.

Host plant. Unknown, adults were collected on grass Setaria megaphyllia Beauv.

Distribution. Cameroon ( fig. 7 ).

Remarks. A member of the Cassida lacrymosa species–group. Next to Cassida humerosa this is the only species with elytral pattern forming broad humeral spots on the explanate margin of elytra. Cassida humerosa is an extremely variable species and only the typical form (fig. 78) of this species is characterized by marbled pattern of elytral disc, especially on sides, a dark spot on the postscutellar elevation and broad humeral spots similar to the pattern of C. camerunensis (fig. 95). Cassida camerunensis has the elytral sculpture less marked, with second interval slightly elevated only in the posterior third (in C. humerosa usually elevated along entire length), punctation of elytra smaller and more regular thus the surface of the disc appears mostly regular (in C. humerosa punctation is coarser, rows are often interrupted by elytral relief thus the surface appears more or less irregular). In C. camerunensis , the base of the elytra is distinctly wider than the pronotum and the spot on the postscutellar elevation forms a narrow stripe while in C. humerosa , the base of the elytra is moderately wider than the pronotum and the spot on the postscutellar elevation is usually round or triangular (figs. 95 vs. 87) only occasionally in the form of a narrow stripe ( fig. 91 ).

Type examined. Holotype: Kamerun ( NRS).

Other specimens examined. CAMEROON: Nkolbison, Younde–Bi, 11 II 1963, 1 ( MNHW); Okola, Nkong r., Yégué, 14 VIII 1963, 1, 16 IX 1963, 1 on Setaria megaphyllia Beauv. (MNHW) .

Figures

FIGURE 7. Distribution of Cassida calvaria (black circles) and Cassida camerunensis (black diamonds).

FIGURES 86–91. Cassida humerosa. 86–87, 89–91. Dorsal; 88. Lateral.