Cryptoxyleborus percuneolus (Schedl, 1951)

Sittichaya, Wisut, Smith, Sarah M. & Beaver, Roger A., 2019, Ten newly recorded species of xyleborine ambrosia beetles (Coleoptera, Curculionidae, Scolytinae, Xyleborini) from Thailand, ZooKeys 862, pp. 109-127 : 121

Cryptoxyleborus percuneolus (Schedl, 1951) Fig. 10 A–E

Xyleborus percuneolus Schedl, 1951: 85.

Xyleborinus percuneolus (Schedl): Wood and Bright 1992: 809.

Cryptoxyleborus percuneolus (Schedl): Beaver and Hulcr 2008: 145.

Diagnosis.

Minute, the smallest Cryptoxyleborus species, 1.4 mm long; elongate, 2.55 times longer than wide; body dull, glabrous except for mycangial tuft along elytral base, red brown to brown in color; antennal club approximately circular, first segment smaller than second (type 4; Hulcr et al. 2007), pronotum from dorsal view elongated basic shape (type 7; Hulcr et al. 2007), anterior margin round, armed with minute serrations, pronotal disc alutaceous, shagreened, from lateral view elongate, with low summit (type 7; Hulcr et al. 2007); elytra stout, 1.75 times longer than pronotum, base sinuate without mycangial pits, disc shining, interstriae distinctly seriate punctate, declivital striae and interstriae granulate, never bearing hooked tubercles, elytra gradually tapering from midpoint to apex.

Material examined.

THAILAND, Ton Nga Chang Wildlife Sanctuary, Songkhla Province, 6°59'32.1"N, 100°08'57.8"E, tropical rainforest, ethanol-baited trap, 01.vi.2015 (1) (W. Sittichaya).

Distribution.

Indonesia (Java), Malaysia (Sabah). New to Thailand.

Biology.

Like other species of Cryptoxyleborus , its hosts are probably confined to trees of the family Dipterocarpaceae ( Beaver and Hulcr 2008). However, no host trees have yet been recorded. One gallery system investigated in an undetermined tree comprised an unbranched entrance tunnel leading to a single terminal brood chamber enlarged in the longitudinal plane, with multiple tunnels extending further into the wood ( Beaver and Hulcr 2008).

Remark.

This species can be distinguished from all other Cryptoxyleborus recorded in Thailand by its minute size (1.4 mm), elytral base sinuate and lacking mycangial pits.

Figures

Figure 10. Cryptoxyleborus percuneolus (Schedl) A lateral view B dorsal view C posterolateral view D front E declivity.