Arixyleborus phiaoacensis, 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

Arixyleborus phiaoacensis sp. nov. Fig. 27G, H, L

Type material.

Holotype, female, Vietnam: Cao Bang, 22°33.118'N, 105°52.537'E, 1048 m, 12-17.vi.2014, VN9, Cognato, Smith, Pham, FIT (MSUC).

Diagnosis.

2.2 mm long (n = 1); 2.75 × as long as wide. This species is distinguished by its moderate size; protibiae slender, slightly broadened distally, posterior faces inflated, granulate; antennal club as broad as tall; pronotum lateral margin oblique; pronotum anterior margin without serrations; posterolateral carina acute, granulate.

Similar species.

Arixyleborus crassior , A. mediosectus , A. silvanus .

Description

(female). Length 2.2 mm (n = 1); 2.75 × as long as wide. Body uniformly red-brown. Legs and antennae yellow-brown. Head: epistoma entire, transverse, lined with a row of hair-like setae. Frons slightly convex from epistoma to upper level of eyes; surface shagreened, dull, punctate; punctures above epistoma large, coarse, shallow; punctures decreasing in size, coarseness, and depth from epistoma to upper level of eyes; area between upper level of eyes reticulate. Eyes deeply emarginate above level of antennal insertion, upper portion of eyes smaller than lower part. Submentum deeply impressed, very narrow, triangular. Scape short and thick, shorter than club. Antennal funicle 4-segmented, segments equal in size. Pedicle as long as funicle. Club wider than long, asymmetrical, club type 1; obliquely truncate, segment 2 not visible on posterior face; segment 1 covering posterior face, its margin completely costate; segment 2 narrow, pubescent with corneous part, visible on anterior face only. Pronotum: 1.25 × as long as wide. In dorsal view long and rounded frontally, type 7, sides parallel in basal 2/3, rounded anteriorly; anterior margin with a row of serrations. In lateral view elongate with disc much longer than anterior slope, type 8, summit low. Surface shagreened, anterior 1/2 finely asperate, asperities close, arranged in concentric rings from midpoint of pronotum to anterior margin; anterolateral areas unarmed; disc minutely and sparsely punctate; punctures bearing minute setae slightly longer than puncture width. Lateral margins obliquely costate. Base weakly bisinuate, median region with a row of setae. Elytra: 1.52 × as long as wide, 1.34 × longer than pronotum. Scutellum moderately sized, linguiform, flush with elytra, flat. Elytral base weakly bisinuate, humeral angles rounded, sides straight from base to apical 1/2 of declivity, then slightly acuminate to apex. Disc longer than declivity, distinctly and abruptly separated; interstriae shiny, minutely, finely uniseriate punctate from base to midpoint, sparsely setose, nearly glabrous, basal 1/2 shagreened, dull, becoming sharply carinate, tuberculate; striae impressed, strial punctures larger, shallower than on apical 1/2, interstriae laterally diverging from base to declivity and narrowed on declivity. Declivity obliquely truncate, densely shagreened, dull, sculpturing consisting of much weaker interstrial carinae and impressed striae; striae punctate, punctures large, shallow; interstriae tuberculate, tubercles small, bearing a short, recumbent seta, less than the distance between tubercles in length; interstriae 1 inflated on apical 1/2; interstriae 1-3 carinae extending to apex of declivity. Posterolateral margin carinate, granulate to interstriae 7. Legs: procoxae contiguous; prosternal posterocoxal piece short, conical. Protibiae slender, slightly broadened distally; posterior faces inflated, granulate; outer margin of apical 1/2 with six small socketed denticles. Meso- and metatibiae flattened; outer margin evenly rounded, seven and eight socketed denticles on outer margin, respectively; posterior face unarmed.

Etymology.

In reference to the type locality, Phia Oac Nature Reserve. Latinized adjective.

Distribution.

Vietnam.

Host plants.

Unknown.

Figures

Figure 27. Dorsal, lateral and declivital view of Arixyleborus minor, 1.2 - 1.4 mm (A, B, I), A. moestus paratype, 2.5 - 2.7 mm (C, D, J), A. nudulus holotype, 1.5 - 1.8 mm (E, F, K), and A. phiaoacensis holotype, 2.2 mm (G, H, L).