Xyleborinus cuneatus, Smith & Beaver & Cognato, 2020

Smith, Sarah M., Beaver, Roger A. & Cognato, Anthony I., 2020, A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China, ZooKeys 983, pp. 1-442 : 1

Xyleborinus cuneatus sp. nov. Fig. 82G, H, L

Type material.

Holotype, female, Thailand: Chiang Mai, Doi Pui, 1400 m, 10-31.i.2005, W. Puranasakul, ex EtOH trap (NHMUK). Paratypes, female, as holotype except: 10-31.v.2005 (RABC, 1); as holotype except: 8-12.xi.2004, flight intercept trap (QSBG, 1).

Diagnosis.

2.1-2.2 mm long (mean = 2.13 mm; n = 3); 3.14-3.23 × as long as wide. This species is distinguished by the elytra parallel-sided in basal 1/2, tapering posteriorly; declivital face with interstriae 1 and 2 unarmed by tubercles; declivital face moderately sulcate; small body size; lateral declivital margins moderately elevated, costate, bearing 4-6 pairs of large sharply pointed backwardly hooked denticles (often asymmetric); elytra with small denticles on interstriae 1-4 extending anteriorly onto the disc to at least the midpoint; strial punctures large; declivital surface shagreened, dull; and elongate body form.

This species is very similar to X. spinipennis and can be recognized by the smaller size and more elongate form, elytra with small denticles on interstriae 1-4 extending anteriorly onto the disc to at least the midpoint, and pronotum more elongate, 1.22 × as long as wide.

Similar species.

Xyleborinus andrewesi , X. disgregus , X. jianghuasuni , X. sculptilis , X. speciosus , X. spinipennis .

Description

(female). 2.1-2.2 mm long (mean = 2.13 mm; n = 3); 3.14-3.23 × as long as wide. Body dark red-brown. Legs and antennae light brown. Head: epistoma entire, transverse, with a row of hair-like setae. Frons weakly convex to upper level of eyes, alutaceous, subshiny, sparsely punctate; punctures large, shallow, setose; punctures bearing a long, erect hair-like seta. Eyes deeply emarginate just above antennal insertion, upper part smaller than lower part. Submentum narrowly triangular, deeply impressed. Antennal scape regularly thick, as long as club. Pedicel as wide as scape, as long as funicle. Funicle 4-segmented, segment 1 shorter than pedicel. Club longer than wide, obliquely truncate, type 1; segment 1 corneous, encircling anterior face; segment 2 narrow, concave, corneous on anterior face only; sutures absent on posterior face. Pronotum: 1.17 × as long as wide. In dorsal view very elongate, rounded frontally, type 9, sides parallel on basal 3/4; anterior margin without serrations. In lateral view elongate with disc much longer than anterior slope, type 8, disc flat, summit prominent at apical 1/3. Anterior slope with densely spaced narrow asperities, becoming lower and more strongly transverse towards summit, bearing long, fine, semi-recumbent, hair-like setae. Disc subshiny, alutaceous, finely punctate, finely setose, setae short, erect, hair-like, some longer hair-like setae at margins. Lateral margins obliquely costate. Base transverse, posterior angles acutely rounded. Elytra: 2.02 × as long as wide, 1.73 × as long as pronotum. Scutellum minute, conical, disconnected from elytra, surrounded by dense mycangial tuft of setae. Elytral base transverse, medially emarginate near scutellum and mycangial tuft, edge oblique, humeral angles angulate, parallel-sided in basal 1/2, then tapering to apex. Disc occupying basal 2/3, smooth on basal 1/2, shagreened and dull on apical 1/2; striae not impressed, glabrous, with moderate punctures separated by one diameter of a puncture; interstriae flat, sparsely finely uniseriate punctate, punctures 1/3 those of striae, each bearing erect, hair-like setae, setae approximately as long as width of interstriae 2; apical 1/2 of interstriae armed by granules medially and increasing in size apically, becoming large denticles at declivital base. Declivital face steeply rounded, impressed between interstriae 1 and 3, appearing bisulcate, strongly shagreened; three striae present, striae parallel, strial punctures slightly larger than on disc, glabrous; interstriae impunctate; interstriae 1 with two denticles present at base, remainder unarmed; interstriae 2 narrow, flat, impressed, unarmed along its length; interstriae 3 elevated on basal 3/4 with a row of with a row of five or six regularly spaced, strong spines. Interstrial denticles and spines setose, setae erect, hair-like, uniseriate, as long as the width between suture and interstriae 3. Posterolateral margin costate, denticulate to interstriae 7. Legs: procoxae contiguous; prosternal coxal piece flat, inconspicuous. Protibiae obliquely triangular, broadest at apical 1/3; posterior face smooth; apical 1/3 of outer margin with six moderate socketed denticles, their length approximately as long as basal width. Meso- and metatibiae flattened; outer margin evenly rounded with eight and five moderate socketed denticles, respectively.

Etymology.

L. cuneatus = wedge-shaped. In reference to the shape of the beetle. An adjective.

Distribution.

Thailand.

Host plants.

Unknown.

Figures

Figure 82. Dorsal, lateral and declivital view of Xyleborinus andrewesi, 1.9 - 2.0 mm (A, B, I), X. artestriatus, 2.3 - 2.8 mm (C, D, J), X. attenuatus, 2.6 - 2.9 mm (E, F, K), and X. cuneatus holotype, 2.1 - 2.2 mm (G, H, L).