Monolepta marginicollis Jacoby, 1896

Hazmi, Izfa Riza & Wagner, Thomas, 2022, Revision of Monolepta Chevrolat, 1836 from the Sundaland area (Coleoptera: Chrysomelidae: Galerucinae), Bonn zoological Bulletin 71 (2), pp. 139-176 : 160-161

Monolepta marginicollis Jacoby, 1896

Figs 9 , 34–35

Monolepta marginicollis Jacoby, 1896: 485 .

Type material. Syntypes: “ Sumatra Si-Rambe , XII.90– III.91, E. Modigliani / Monolepta marginicollis Jac. / Museo Civ. Genoa / Jacoby Coll. 1909-28a / Co-type” ( BMNH; Fig. 34 ). One further sytpe with the same data in MCGD. Type locality: 6º11′ S / 106º48′ E .

Further material examined. – Brunei. 4 ex., Labi, Bukit Teraja 60 m, Mxt. Dipt. Forest , 4º18′ N / 114º26′ E, 21. VIII .1979, B.M. 1983-39, Light trap, 1.75 m above ground, S. L. Sutton ( BMNH) ; 7 ex., Bukit Sulang nr Lamunin , 4º39′ N / 114º44′ E, 20. VIII .–10.IX.1982, NE Stork ( BMNH) ; 1 ex., Kuala Belalong FSC , Dipterocarp Forest , 4º29′ N / 115º11′ E, 16. VI .1991, N Mawdsley ( BMNH) ; 2 ex., Temburung District Ridge, NE of Kuala Belalong, 4º37′ N / 115º8′ E, 300 m, X.1992, Light Trap, J. H. Martin ( BMNH) . – Indonesia. 1 ex., N Sumatra, Bivouac Two, Mt Bandahara , 3º44′ N / 97º43′ E, 5.–10. VII .1972, J. Krikken ( RMNH) . – Malaysia. 3 ex., Borneo, Mt. Tibang , 1700 m, Mjoberg ( NHRS) ; 3 ex., Mt. Matang , West Sarawak, XII .1913– II.1916, G. E. Bryant ( BMNH) ; 1 ex., Malay Penin , Kedah Peak, 16. III .1928 ( BMNH) ; 1 ex., Sarawak, Engkelili , 1º8′ N / 111º39′ E, 27. VIII .1967, Vincent Coll. ( BMNH); 3 ex., Sarawak, Gunong Mulu Nat. Park , 3º55′ N / 114º47′ E, R . G. S. Exped. 24. VI .1977, J. D. Holloway et al. ( BMNH) ; 11 ex., Sabah, Tawau Plat. 1300 ft., 8 m S. Telupid , 5º35′ N / 117º07′ E, 8.IX.1977, M. E. Bacchus ( BMNH) ; 19 ex., Sarawak, 4th Division Gn. Mulu NP, nr. Base Camp 50–100 m, 3º55′ N / 114º46′ E, V .– VIII .1978, P. M. Hammond & J. E. Marshall ( BMNH) ; 1 ex., Malaysia-SW, Sabah nr Long Pa Sia (west), 5º20′ N / 117º10′ E, 1200 m, 2.–14.IV.1987, C. v. Achterberg ( RMNH) ; 2 ex., Malaysia, SE Sabah nr Danum Valley Field C, 5º25′ N / 118º23′ E, 15.–25. III .1987, C. v. Achterberg & D. Kennedy ( RMNH) ; 1 ex., N. Borneo , Sabah, 60 km of Lahad Datu DVFC, EO sg. Segama , 4º58′ N / 117º48′ E, 18.X.1987, J. Huisman & R . de Jong ( RMNH) ; 1 ex., Sabah, Sandakan, Sepilok FR (obs tower), 5º51′ N / 118º0′ E, 1.XI.1987, Krikken & Rombaut ( RMNH) ; 1 ex., Pahang, Kuala Lompat , 3º41′ N / 102º11′ E, 27. VIII .1990, Fog Malathion, Mahbob ( UKM) ; 1 ex., Sabah, Lembah Danum , 5º25′ N / 118º23′ E, 3.–5. XII .1991, Zaidi et al. ( UKM) ; 1 ex., N. Borneo, Trus Madi , 5º43′ N / 116º25′ E, 11.IV.1993, H. Karube ( CTJ) ; 1 ex., Sarawak, Lundu, T . Negara Gunung Gading , 1º44′ N / 109º50′ E, 22.–27. IV.1994, Salleh dan Ismail ( UKM) ; 1 ex., W. Perak, 25 km NE Ipoh, Banjaran Titiwangsa Mts. Korbu , 4º41′ N / 101º18′ E, 6.–12. V .2001, M. Riha ( CJB) .

Redescription

Total length. 3.25–4.00 mm (mean 3.55 mm, n = 10).

Head. Very finely punctuated, yellowish to red- dish-brown, vertex often with short median black stripe. Labrum and mandible black. Antenna slender, extending almost to the middle of elytra, blackish, and three basal antennomeres yellow-brownish ( Fig. 35A ). Third antennomere significantly longer than second; ratio length of second to third antennomere 0.67–0.75 (mean 0.73); ratio length of third to fourth antennomere 0.43–0.67 (mean 0.62) ( Fig. 35B ).

Thorax. Pronotum finely punctuated, yellow to brown- ish-yellow, lateral and basal margin black ( Figs 34b , 35A ). Pronotal width 1.00– 1.20 mm (mean 1.06 mm), ratio length to width 0.60–0.64 (mean 0.62). Scutellum, meso- and metathorax blackish. Elytron finely punctuat- ed, yellowish, all margins, including suture, black. Elytral length 2.45–2.85 mm (mean 2.68 mm), maximal width of both elytra together 1.80–2.10 mm (mean 1.96 mm), ratio of maximal width of both elytra together to length of elytron 0.71–0.74 (mean 0.73). Legs entirely yellowish.

Abdomen. Yellowish, strongly contrasting to the black metathorax.

Male genitalia. Median lobe slender, parallel-sid- ed, conidal in the apical third. Tectum pointed. Median spiculae three broad spines, further brush-like structures at sacculus ( Figs 35 Ca, Cb), lateral spiculae short spurs close to apex, ventral spiculae as two fattened, spiny structures ( Figs 35 Ca, Cb).

Female genitalia. Spermatheca with spherical comparatively big nodulus and small ridge. Cornu very long and curved ( Fig. 35D ). Bursa sclerite very weakly sclerotised and hardly visible.

Diagnosis. Most similar to M. marginicolloides sp. nov. on the first glance. Both species have yellow elytra with a slightly stripy appearance and narrow black outer elytral margins and suture in common ( Figs 34A , 52b ). Antennomeres in both species are blackish and only three basal antennomeres yellowish. Monolepta marginicollis is on average smaller (3.25–4.00 mm) than M. marginicolloides sp. nov. (3.70–5.10 mm). Other characters to differentiate these two species are the yellow-brownish head and vertex with short central black stripe in M. marginicollis , while head in M. marginicolloides sp. nov. is completely black. The genitalic characters are very different, and allow a clear differentiation of both species in any doubtful cases ( Figs 34C, D , 53C–E ).

Distribution. Known from Sumatra, Malayan Peninsula and Borneo ( Fig. 9 ).

Figures

Fig. 9. Distribution of Monolepta rubra (Gyllenhal, 1808) and Monolepta marginicollis, Jacoby, 1896.

Fig. 34. Type material of Monolepta marginicollis Jacoby, 1896, syntype (BMNH).

Fig. 35. Monolepta marginicollis Jacoby, 1896. A. Colour pattern. B. Basal antennomeres. C. Median lobe, a. dorsal, b. lateral, c. ventral, without endophallic structures. D. Spermathecae.

Fig. 52. Type material of Monolepta marginicolloides sp. nov., holotype (BMNH).

Fig. 53. Monolepta marginicolloides sp. nov. A. Colour pattern. B. Basal antennomeres. C. Median lobe, a. dorsal, b. lateral, c. ventral, without endophallic structures. D. Spermathecae. E.Bursa-sclerites, a. dorsal, b. ventral.