Xyleborinus jianghuasuni, 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 jianghuasuni sp. nov. Fig. 84C, D, J

Type material.

Holotype, female, China: Yunnan, Xishuangbanna, Sanchahe Nat[ure]. Res[erve]., 22°09.784'N, 100°52.256'E, 2186 m, 29-30.v.2008, A.I. Cognato, ex Quercus (IZAS). Paratypes, female, as holotype (MSUC, 2).

Diagnosis.

1.8 mm long (n = 3); 3.0 × as long as wide. This species is distinguished by the posterior margin of elytra broadly rounded; declivital face with interstriae 1 and 2 unarmed by tubercles; declivital face feebly sulcate; small body size; lateral declivital margins weakly elevated, bearing three pairs of sharply pointed denticles, denticles subequal; denticles along interstriae 5 subequal to those on interstriae 3; sulcate area impunctate, surface strongly shagreened, dull; and elongate body form.

Similar species.

Xyleborinus cuneatus , X. disgregus , X. sculptilis .

Description

(female). 1.8 mm long (n = 3); 3.0 × as long as wide. Body uniformly 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, finely, sparsely punctate, 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 short and 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: 1.25 × 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 moderately 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: 1.93 × as long as wide, 1.54 × 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 3/4, then broadly rounded to apex. Disc occupying basal 2/3, smooth, shiny, unarmed; striae not impressed, with large punctures separated by one diameter of a puncture, setose, setae recumbent, as long as the diameter of a puncture; interstriae flat, sparsely finely uniseriate punctate, punctures 1/4 those of striae, each bearing erect hair-like setae, setae approximately as long as width of interstriae 2. Declivital face strongly shagreened, dull, steeply rounded, feebly sulcate between interstriae 3, impunctate; three parallel striae present; interstriae impunctate, flat; interstriae 1 unarmed on face, two or three denticles present at base; interstriae 2 unarmed along its length, one small denticle at base; interstriae 3 weakly elevated, bearing three pairs of sharply pointed denticles, denticles subequal; interstrial denticles setose, setae erect, hair-like, uniseriate and as long as the width between suture and interstriae 3. Posterolateral margin costate, granulate to interstriae 7. Legs: procoxae contiguous; prosternal coxal piece tall and pointed. Protibiae obliquely triangular, broadest at apical 1/3; posterior face smooth; apical 1/3 of outer margin with five moderate socketed denticles, their length approximately as long as basal width. Meso- and metatibiae flattened; outer margin evenly rounded with seven moderate socketed denticles.

Etymology.

In gratitude for the assistance of Dr. Jianghua Sun (Chinese Academy of Sciences) who facilitated AIC’s access to wild China. Noun in genitive.

Distribution.

China (Yunnan).

Host plants.

This species is only known from Quercus ( Fagaceae ).

Figures

Figure 84. Dorsal, lateral and declivital view of Xyleborinus huifenyinae holotype, 1.7 mm (A, B, I), X. jianghuasuni holotype, 1.8 mm (C, D, J), X. octiesdentatus, 2.5 - 2.65 mm (E, F, K), and X. perpusillus, 1.6 - 1.9 mm (G, H, L).