Xyleborinus thaiphami, 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 thaiphami sp. nov. Fig. 86G, H, L

Type material.

Holotype, female, Vietnam: Cao Bang, 22°36.402'N, 105°52.397'E, 1601 m, 13.iv.2014, VN17, Cognato, Smith, Pham, ex standing stump (MSUC). Paratypes, female, China: Chongqing Mun., Wu Xi, viii.2015, Wang, J-L, Lv-Jia, Tian-Shang, ex Pinus armandii Franch. (RABC, 1); Guizhou, Guiyang, Huaxi, 25.x.2015, You Li, ex trap baited with ipsenol & EtOH (MSUC, 1); Sichuan, Emei Shan, 17.viii.2016, Tian-Shang (RABC, 1); Vietnam: Cao Bang, 22°36.804'N, 105°51.982'E, 1831 m, 17.iv.2014, VN44, Cognato, Smith, Pham, ex fallen tree, 10 cm branch (MSUC, 1; VNMN, 1); as previous except, VN45, ex 5 cm branch (NMNH, 1).

Diagnosis.

2.8-2.9 mm long (mean = 2.86 mm; n = 5); 2.9-3.11 × as long as wide. This species is distinguished by the declivital face with interstriae 2 armed by granules at declivital summit (1-3 large denticles present in Vietnamese specimens), unarmed on declivital face; declivital interstriae 3 denticles larger than those of interstriae 1, pointed, spine-like; denticles on interstriae 5 large, sharply pointed, spine-like; discal interstriae 1 and 2 unarmed; declivital interstriae 2 flattened; and large size.

This species is nearly identical to X. attenuatus and is distinguished by the declivital interstriae 3 denticles which are acutely pointed rather than incurved, and interstriae 5 denticles never down-curved.

Similar species.

Xyleborinus attenuatus , X. saxesenii , X. subgranulatus , X. subspinosus .

Description

(female). 2.8-2.9 mm long (mean = 2.86 mm; n = 5); 2.9-3.11 × as long as wide. Body light to dark 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 shallowly emarginate just above antennal insertion, upper part smaller than lower part. Submentum large, distinctly triangular, deeply impressed. Antennal scape regularly thick, shorter than club. Pedicel as wide as scape, shorter than 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: 1.04 × as long as wide. In dorsal view long and rounded frontally, type 7, sides parallel in basal 3/4, rounded anteriorly; anterior margin without serrations. In lateral view elongate, disc much longer than anterior slope, type 7, summit prominent, on anterior 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: 1.8 × 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 rounded, parallel-sided in basal 3/4, then weakly rounded to apex. Disc occupying basal 2/3, smooth, shiny, unarmed; striae not impressed, glabrous, with moderate punctures separated by two diameters 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. Declivital face strongly shagreened, steeply rounded, three striae present, striae parallel, strial punctures as large as on disc, glabrous; interstriae impunctate, setose, setae uniseriate and as long as the width between suture and interstriae 3; interstriae 1 weakly convex, widened from base to declivital midpoint, then narrowed to apex, basal 1/2 armed with three small denticles; interstriae 2 flat, parallel, armed by granules only at declivital summit (1-3 denticles present in some specimens), unarmed on declivital face; interstriae 3 with a row of four large denticles along its length, their apices acutely pointed, spine-like. Posterolateral margin rounded, denticulate from interstriae 3-5. Legs: procoxae contiguous; prosternal coxal piece slightly inflated, conical. 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 ten and nine moderate socketed denticles, respectively.

Etymology.

Named after our collaborator Dr. Thai Hong Pham who first saw the standing dead tree in which the holotype was living and who then sawed the tree down with great enthusiasm. Noun in genitive.

Distribution.

China (Chongqing, Guizhou, Sichuan), Vietnam.

Host plants.

This species is only known from Pinus armandii ( Pinaceae ).

Figures

Figure 86. Dorsal, lateral and declivital view of Xyleborinus spinipennis, 2.3 - 2.75 mm (A, B, I), X. subgranulatus, 1.6 - 1.8 mm (C, D, J), X. subspinosus holotype, 2.3 mm (E, F, K), and X. thaiphami holotype, 2.8 - 2.9 mm (G, H, L).