Amasa opalescens (Schedl, 1937)

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 : 115

Amasa opalescens (Schedl, 1937) Fig. 4 A–E

Xyleborus opalescens Schedl, 1937: 550

Amasa opalescens (Schedl): Wood and Bright 1992: 683.

Diagnosis.

Large, 4.5 mm long (N = 1); moderately stout, 2.5 times longer than wide; body shining, declivity opalescent, brown in color; eye deeply emarginated, almost completely divided; antennal club with first segment smaller than second (type 4; Hulcr et al. 2007); pronotum from dorsal view round (type 1; Hulcr et al. 2007), from lateral view tall (type 2; Hulcr et al. 2007), anterior margin round, armed with 6 small asperities, anterior portion of pronotum densely asperate, base shagreened; elytra 1.24 times longer than pronotum, lateral sides subparallel, widest at declivital summit, disc shining, striae minutely punctate, interstriae four times broader than striae, broadest at declivital summit, declivital margin unarmed, declivity smooth,opalescent, strial punctures large, irregularly spaced.

Material examined.

Thailand, Bang Lang National Park, Yala Province, Thailand-Malaysia border, 5°48'51.8"N 101°17'14.7"E, ex. small branches of unknown tree, 01.ii.2014 (1).

Distribution.

‘Borneo’, East and West Malaysia, Vietnam. New to Thailand.

Biology.

Recorded from Eugenia sp. and Tristania sp. ( Myrtaceae ), and possibly with a fixed association with this family ( Browne 1961).

Remarks.

This species can be distinguished from all other Amasa recorded in Thailand by its large size (4.5 mm), moderately stout form (2.5 times longer than wide), declivital summit entirely carinate without teeth on first interstriae, declivity smooth, subshining, opalescent, strial punctures large, irregularly spaced, and eye deeply emarginated, almost completely divided.

Figures

Figure 4. Amasa opalescens (Schedl, 1937) A lateral view B dorsal view C posterolateral view D front F declivity.