Thriocerodes decussates, Bartlett, 2009

Bartlett, Justin S., 2009, The Cleridae of Lord Howe Island, with Descriptions of Two New Species (Coleoptera: Cleroidea), Records of the Australian Museum 61 (3), pp. 225-228 : 226-227

Thriocerodes decussates n.sp.

Fig. 1

Type material. Lord Howe Island: HOLOTYPE: AMS K185981 , 1 /3 way up Goat House Trail (1st patch of palms) (31°33'47"S 159°05'09"E), 23 Nov. 2001, C.Reid, beating palms etc, c. 280 m. PARATYPE (1): AMS K185982 , same data as holotype .

Diagnosis. Small, compact, flightless; dorsum densely vested with fine setae; pronotum strongly convex; body black-brown with yellow X-shaped maculation across basal half of elytra; unlikely to be confused with any other clerid on Lord Howe Island.

Description. Total length: 3.4–4.1 mm. Head black-brown basally, frons medially and clypeus red-brown; frons, vertex and genae behind eyes distributed with a dense network of wrinkled punctation, densely vested with long pale posteriorly directed setae; eyes without distinct emargination; genae ventrally foveolate to smooth; gula smooth; labrum yellow-orange; maxillae and labium pale yellow; distal margins of terminal palpomeres slightly shorter than inner margins; antennae almost reaching pronotal base, vested with erect setae, pedicel and scape yellow, globular, A3–8 orange-brown, A3 elongate, A4–8 becoming progressively sub-globular, club dark brown, approximately as long as combined length of A5–8, A9–10 cupuliform, wider than long, their apical circumferences lined with a ring of short, white, forward directed setae, terminal segment obliquely rounded to vaguely trapezoidal. Prothorax black-brown, transverse (length:width = 0.9:1), sub-spherical; disc subglabrous though densely distributed with conspicuous circular foveolate punctation, densely vested with fine, pale, anteriorly positioned/posteriorly directed and posteriorly positioned/anteriorly directed setae, plus several longer erect setae. Elytra compact (length:width = 1.6:1), black-brown; basal half punctate, with a large yellowish X-shaped maculation, apical half smooth; punctations without internal nodules, reduced to smooth circular subfoveolate impressions arranged in poorly-defined rows, those within black-brown area either side of X-shaped pattern more deeply impressed; disc densely vested with fine posteriorly directed setae plus several slightly thicker erect setae. Mesosternum dark brown, impressed with foveolate punctation. Metasternum dark brown laterally, orange brown medially, surface foveolate anteriorly, smooth posteriorly. Abdomen dark brown laterally, orange-brown medially; posterior margins of ventrites 2–4 transversely bordered by a pale orange band. Legs short, variously vested with short semi-decumbent, and long erect, setae; femora and tibiae dark brown, inner surface of femoral bases lightly infused with yellow; tarsi yellow.

Etymology. The specific epithet is descriptive of the distinctive pale X-shaped maculation of the elytra (Latin, decusso = the Roman numeral X).

Biology. The holotype and single paratype were beaten from palms.

Remarks. Although differing from typical Thriocerodes by its rounded pronotal disc and virtual absence of ocular emargination, no substantial characters were identified on which to base the exclusion of T. decussates n.sp. from the genus. Its assignment to Thriocerodes is based on the following shared characters: eyes widely separated, coarsely facetted; terminal palpomeres securiform; procoxal cavities open posteriorly; prothorax with complete lateral carina (which converges with the posterior margin of the hypomeron at the prothoracic hind angle); elytra compact, punctation not internally nodulate, epipleura converging near start of apical curve; legs short; tibial spur formula 1-2-1, pro- and meso-tarsi each with three pulvilli.

Figures

Figure 1. Thriocerodes decussates n.sp. holotype, scale = 1 mm.