Cassida thomsoni Boheman, 1862

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 : 161-163

Cassida thomsoni Boheman, 1862

( figs. 46 , 176–178 )

Cassida Thomsoni Boheman, 1862: 302 ; Gemminger & Harold, 1876: 3659; Shaw, 1963: 457; Borowiec, 1995: 371, 1999 a: 288, 2005 a: 127.

Cassida (Cassida) Thomsoni: Spaeth, 1914 b: 119 .

Cassida (Odontionycha) Pentheri Spaeth, 1905: 109, 1914 b: 119 (as syn.).

Description. L: 5.75–6.80 mm, W: 4.45–4.90 mm, Lp: 2.20–2.40 mm, Wp: 3.80–4.20 mm, L/W: 1.29–1.45, Wp/ Lp: 1.68–1.75. Body elongate–oval ( figs. 176, 177 ).

Pronotum yellow to ochraceous, disc usually darker from explanate margin, sometimes with short brownish stripe in front of scutellum, occasionally with diffused darker ochraceous M–shaped spot. Scutellum yellow, elytral disc with mixed yellow and ochraceous pattern. Usually punctures have ochraceous centre and areola and elevated parts of disc are yellow, sometimes yellow are also sides of disc and slope, in extreme dark specimens ochraceous colour occupies most of elytral sides and punctures on top of disc, yellow elevated second interval in 1/3 and half length with ochraceous stripe. Explanate margin of elytra yellow to ochraceous, usually paler than ground colour of disc ( figs. 176, 177 ). Head, ventrites and legs yellow. Antennal segments 1–6 yellow, segment 7 more or less infuscate, last four apical segments brown to black.

Pronotum elliptical, with maximum width at base, anterior margin regularly convex, sides angulate. Disc indistinctly bordered from explanate margin, without lateral lobes or lateral impressions. Surface of disc more or less alutaceous, sculpture variable from only microreticulate with small pricks to distinctly, finely and densely punctate thus surface of disc appears slightly irregular. Explanate margin broad, impunctate, dull, semitransparent with more or less visible honeycomb structure.

Base of elytra not or slightly wider than base of pronotum, humeral angles moderately protruding anterad, angulate. Disc slightly depressed in profile ( fig. 178 ), with very shallow postscutellar and distinct principal impressions, usually without H–shaped elevation but with elevated, sharp, linear second interval, sometimes in postscutellar area transverse, flat incomplete folds imitate H–shaped elevation but never complete, yellow parts of disc usually more or less elevated, partly impunctate form a relief. Punctation moderately coarse, dense, in most parts of disc irregular, only submarginal and sutural rows partly regular, distance between punctures in dark parts of disc mostly narrower than puncture diameter but on yellow relief punctures often in greater distance. Marginal row distinct, its punctures slightly coarser than punctures in central rows. Intervals obsolete except sharp second interval and sometimes short elevated line in position of the middle of fourth interval, marginal interval as wide as submarginal interval and two submarginal rows combined, humeral or lateral folds indistinct or obsolete but often elevated interspaces of marginal row extend to space of marginal interval. Entire surface of disc alutaceous. Explanate margin narrow, moderately declivous, in the widest part six times narrower than disc, surface alutaceous fine and sparse punctation, appears slightly irregular, semitransparent with more or less visible honeycomb structure.

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, surface of clypeus flat or very shallowly impressed, shiny with few very small, setose punctures, area between clypeal grooves and margin of eye with a row of hairy punctures. Labrum broadly emarginate to 1/4 length. Antennae moderately slim, segments 9–10 slightly longer than wide. Length ratio of antennal segments: 100:50:90:57:50:43:53:47:53:57:100. Segment 3 approximately 1.8 times as long as segment 2 and approximately 1.6 times as long as segment 4.

Prosternum moderately broad in the middle, strongly expanded apically, area between coxa flat without special sculpture except several very small, setose punctures, expanded apex flat, shiny, with a transverse row of small setose punctures.

Claws with large basal tooth.

Host plant. Tiliaceae : Grewia bicolor Juss. (label data, H. Heron pers. comm.)

Distribution. Southern Africa north to Malawi ( fig. 46 ).

Remarks. Cassida thomsoni and C. weinmanni form a group of moderately size species (length above 5 mm, below 7 mm) with a slightly elongate body (L/W 1.29–1.49), alutaceous surface of dorsum, colouration of pronotum and elytra from ochraceous to brown forming a marbled pattern or numerous, small dark spots ( figs. 176 –181). Cassida weinmanni differs in broadly rounded pronotal sides (angulate in C. thomsoni ), surface of pronotum more or less irregular and finely granulate (almost regular in C. thomsoni ), elytral disc with numerous small brown spots (rather with marble pattern or with only few dark spots in C. thomsoni ) and simple claws (with large basal tooth in C. thomsoni ). Both species are widely separated geographically, C. thomsoni is distributed in southern Africa north to south Malawi while C. weinmanni is known from Ethiopia and Eritrea.

Types examined. Holotype of Cassida thomsoni Boheman, 1862 : [ SOUTH AFRICA]: Lake N’Gami (BMNH); 8 syntypes of Cassida (Odontionycha) pentheri Spaeth, 1905 : [FORMER RHODESIA]: Zambesi, 1878, Bradshaw (ITZ); two syntypes of Cassida (Odontionycha) pentheri Spaeth, 1905 : [ SOUTH AFRICA]: Süd–Africa, Dr. Penther (MM).

Other specimens examined. BOTSWANA: Gaberones , 1915, 1 ( MM) , 1915, 1, R. Ellenberger ( MNHN) ; SW Ghanzi, Tsao , IX–XI 1961, 1, Kalahari Exp. ( MNHW) ; Kasane , 1 I 1994, 2, M. Snižek ( MS) ; Maun, Island Safari Lodge env., 2–15 I 1994, 1, M. Snižek ( MS) .

MALAWI: Nkopola Forest Res., 20–21 I 1985, 500 m, 2, C.L. Bellamy et al. ( ER) .

NAMIBIA: Abachaus, Oijiwarongo , III 1950, 4, G. Hobohm ( TM, MNHW) , II 1953, 1, G. Hobohm ( ZSM) ; Damaraland, Abachaus , I 1947, 1, XII 1951, 1, G. Hobohm ( TM) ; Grootfontein, Farm Otjna , 5–7 X 1991, 1, U. Göllner ( ZMHU) ; Kamangeb. , 18 IV 1960, 1 ( WM) ; Kavango, Rundu , Okavango riv., 1050 m, 30 I–3 II 1999, 1, R. Kmeco ( JB) ; Kungveld, Tsumkwe , I 1958, 4, C. Koch ( TM, MNHW) ; Okavango, Kapako , 16 XII 1954, 1 ( WM) .

SOUTH AFRICA: Limpopo, Meletse , 1190 m, -24.5888 / 27.6623, 10 XII 2019, 1, P. Jałoszyński ( MNHW) ; Limpopo Prov., Nwanedi Resort, Venda , 22°38’S, 30°24’E, 1 ( ARC) ; Metsimahlaba , 7–12 III 1930, 1, Kalahari Exp. ( TM) ; North Prov., Geelhoutbosh farm, Waterberg , 24.22 S 27.33 E, 15–18 XI 1997, 1, S. Bily ( JV) ; Pentonville , NW Kaalwater, 27 IX 1953, 1, Harvey & Rorke ( TM) ; Sand River Mts. , 18–19 XII 1985, 1, 31 I–1 II 1986, 1, 5–7 II 1986, 2, D. d’Hotmann ( ER) ; Transvaal, Rusterwinter , II 1953, 1, W.G. Kobrow ( TM) ; Transvaal, Kruger Nat. Park , XI 1959, 1, E. Haaf ( MNHW) ; Transval, Sand Riv. Mt. , 24.32 S / 27.39 E, 5–7 II 1986, 1, Bellamy & Westcott ( MNHW) .

ZAMBIA: Katondwe mission, 15.10 S / 30.15 E, XII 1933, 1 ( MNHW); Livingstone, 11 I 1944, 1, E. Eichler ( MNHW) .

ZIMBABWE: Bulawayo, Fortunes Gate , 19 VII 1976, 1, T. Donnelly ( NMM) ; 60 km N Bulawayo, Maraposa Rd. , 3 XII 1998, 1, M. Snižek ( MS) ; 50 km S Bulawayo, Matobo , 3–5 XII 1998, 1, M. Halada ( MS) ; 20 km W Gwanda , 120 km SE Bulawayo, 6 XII 1999, 3, F. Kantner ( FK) ; Hwange , 4 XII 1998, 1, M. Snižek ( MS) ; Matobo, Hills Lodge , 20°29’07’’S / 28°28’41’’E, 17 XII 1998, 1, M. Rice ( MER) .

Figures

FIGURE 46. Distribution of Cassida tarda (black circles) and Cassida thomsoni (black diamonds).

FIGURES 176–178. Cassida thomsoni. 179–181. Cassida weinmanni. 176–177, 179–180. Dorsal; 178, 181. Lateral.