Genyocerus borneensis (Browne)

Beaver, R. A. & L. - Y, 2007, A review of the genus Genyocerus Motschulsky (Coleoptera: Curculionidae: Platypodinae), with new synonyms and keys to species, Zootaxa 1576 (1), pp. 25-56 : 34

Genyocerus borneensis (Browne)

( Figs 5–7 )

Diapus borneensis Browne, 1980b: 500 .

Genyocerus borneensis (Browne) : Beaver, 1998: 185.

Taxonomy: We have examined the male holotype (BMNH) and a series of specimens collected by S. Adebratt in East Malaysia (Sabah) (ZMLU), which includes both sexes. The species was transferred from Diapus to Genyocerus by Beaver (1998). The female is described here for the first time. It is characterised by the presence of two narrow, forwardly directed, diverging pencils of hairs on the lower part of the frons and by a patch of small mycangial pores in addition to the one or two large pores on each side of the pronotal midline.

Female: Generally resembling male, 2.7 mm long (excluding frontal hair brushes and part of abdomen extending beyond elytra), about 4.1 times as long as wide. Frons weakly convex above epistoma, shallowly, transversely impressed above antennal insertions, just above epistoma and close to midline on each side, a pencil–like brush of long, pale yellow hairs, directed anteriad and somewhat ventrad, each brush inserted on a slightly raised base, cylindrical near base, tapering towards tip, brushes parallel close to base, then divergent, between their insertions on lower part of frons in midline a small tuft of much shorter, ventrally directed hairs ( Fig. 7 ). Antennae inserted at level of lower margin of eyes, club oval, with a few longer hairs, pubescent to base except for a narrow corneous strip along posterior margin, as in male. Pronotum about 1.3 times as long as wide, slightly more elongate than in male, one or two large mycangial pores on each side of midline close to base, and lateral to these a group of about 25–40 much smaller pores. (In the male, a patch of about 12–15 small pores laterally to the pair of large mycangial pores was not mentioned by Browne (1980b) in his description.) Elytra 1.7–1.8 times as long as pronotum, 2.1–2.2 times longer than wide, carina at base of elytra reduced and restricted to humeral region, not extending to scutellum as in male, a row of long semi– recumbent hairs on interstriae 3 (as in male), lacking spines at apex of elytral disc, elytral apices separately rounded. Fifth ventrite plano–concave, without a distinct median groove, lateral margins indistinct, vestiture a little shorter and less dense than in male, largely confined to marginal areas.

Female specimens examined: MALAYSIA: Sabah, Sipitang, Mendolong , 26.xi.1987, 27.xi.1987, various dates from 13.iv.–11.v.1988, 19.ii.1989 (S. Adebratt) (16 ♀) ( ZMLU, RAB) .

Distribution: The species was previously known only from specimens intercepted in Japan in timber shipped from East Malaysia (Sabah and Sarawak) ( Browne 1980b, Ohno 1990b). The occurrence of the species in Sabah can now be confirmed, and it is recorded for the first time from Brunei Darussalam.

New Records: BRUNEI, 115 o 7'E, 4 o 34'N, Kuala Belalong FSC, Dipterocarp forest , site 16–2, 520m alt., Fog 28, 18.iii.1992 (N. Mawdsley) (1 ♂) ( BMNH); MALAYSIA: Sabah, Sipitang, Mendolong, 26.xi.1987, 27.xi.1987, various dates from 13.iv.–13.v.1988, 19.ii.1989, 19.iii.1989 (S. Adebratt) (23 ♂, 16 ♀) ( ZMLU, RAB) .

Biology: Recorded from four genera of Dipterocarpaceae ( Anisoptera , Dipterocarpus , Dryobalanops , Shorea ) and from ' Sapotaceae sp.' ( Ohno 1990b).

Figures

PLATE 2. FIGURE 5. Genyocerus borneensis (Browne) dorsal view of male. FIGURE 6. Genyocerus borneensis (Browne) lateral view of male elytra. FIGURE 7. Genyocerus borneensis (Browne) fronto–dorsal view of female head.