Cyclorhipidion xeniolum, 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

Cyclorhipidion xeniolum sp. nov. Fig. 46E, F, K

Type material.

Holotype, female, China: Yunnan, Xishuangbanna, Sanchahe Nat. Res., 22°09.784'N, 100°52.256'E, 2186 m, 29-30.v.2008, A.I. Cognato (IZAS). Paratypes, female, Thailand: Chiang Mai, Doi Pui, 1400 m, 20-24.xii.2004, W. Puranasakul, ex flight intercept trap (QSBG, 1); as previous except: 21.ii-14.iii.2005, ex EtOH trap (QSBG, 1); as previous except: 14.iii-4.iv.2005 (RABC, 1); as previous except: ii. 2005, ex Castanopsis sp. (RABC, 2).

Diagnosis.

1.65-1.8 mm long (mean = 1.71 mm; n = 5); 3.09-3.4 × as long as wide. This species is distinguished by the short, obliquely truncate and flat declivity that is approximately 25% of total elytral length, armed with large tubercles on interstriae 1 and 3; interstriae 2 always unarmed; posterolateral margins rounded; declivital interstriae 1 and 2 setae uniseriate (Table 1 ).

Similar species.

This species is a part of a challenging species group consisting of C. bodoanum , C. distinguendum , C. inarmatum , C. pelliculosum and C. tenuigraphum (Table 1 ).

Description

(female). 1.65-1.8 mm long (mean = 1.71 mm; n = 5); 3.09-3.4 × as long as wide. Body, antennae, and legs light brown. Elytra slightly darker than rest of body. Head: epistoma entire, transverse, with a row of hair-like setae. Frons weakly convex to upper level of eyes; surface subshiny, impunctate, alutaceous, finely rugose. Eyes deeply emarginate just above antennal insertion, upper part smaller than lower part. Submentum narrow, triangular, deeply impressed. Antennal scape short and thick, shorter than club. Pedicel narrower than scape, as long as funicle. Funicle 3-segmented, segment 1 shorter than pedicel. Club approximately circular and flat, type 3; segment 1 corneous, transverse on anterior face, occupying approximately 2/5 of club; segment 2 narrow, soft; segments 1 and 2 present on posterior face. Pronotum: 1.32 × 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 at apical 1/4. Anterior slope shagreened, with densely spaced, fine, narrow asperities, becoming lower and more strongly transverse towards summit, bearing long, fine, semi-recumbent, hair-like setae. Disc subshiny, alutaceous, densely, finely punctate, finely setose, setae short, erect, hair-like. Lateral margins obliquely costate. Base transverse, posterior angles broadly rounded. Elytra: 1.79 × as long as wide, 1.35 × as long as pronotum. Scutellum moderate, broad, linguiform, flush with elytra, flat, shiny. Elytral base transverse, edge oblique, humeral angles rounded, parallel-sided in basal 4/5, then broadly rounded to apex. Disc flat, shiny, striae and interstriae moderately setose, setae long, semi-recumbent, hair-like, striae not impressed, punctures large, uniseriate, spaced by one diameter of a puncture; interstriae not impressed, minutely punctate, punctures less than 1/2 size of strial punctures, strongly confused, separated by more than five diameters of a puncture. Declivity occupying 1/4 of elytra, obliquely truncate, declivital slope very steep, flat, weakly medially concave between suture and interstriae 3, strongly shagreened, separation between the smooth, shiny disc and shagreened declivity distinct; three striae present, striae 2 closer to striae 1 than striae 3, striae weakly impressed, punctures very large, shallow, subcontiguous, shagreened, much larger than on disc; interstriae 1 and 3 feebly convex, interstriae 2 flat, interstriae minutely punctate, punctures seriate, interstriae 1 and 2 bearing a single row of setae on declivital face, interstriae 3 and 4 bearing two rows of setae, setae long, semi-erect; interstriae 1 with three tubercles, two on apical 1/4 and one on basal 1/3, interstriae 3 with three equally spaced tubercles, one at base, midpoint and on apical 1/4, interstriae 2 unarmed. Posterolateral margin rounded, granulate, extending to interstriae 7. Legs: procoxae contiguous; prosternal coxal piece tall and pointed. Protibiae semi-circular with evenly rounded outer edge, 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 broad, flattened; outer margin evenly rounded with eight and seven moderate socketed denticles, respectively.

Etymology.

L. xenium = a gift to a guest; - olum = diminutive suffix. In reference to AIC’s appreciation of finding such a dainty species. A noun in apposition.

Distribution.

China (Yunnan), Thailand.

Host plants.

Known only from Castanopsis ( Fagaceae ).

Figures

Figure 46. Dorsal, lateral and declivital view of Cyclorhipidion umbratum holotype, 3.8 mm (A, B, I), C. vigilans, 5.5 mm (C, D, J), C. xeniolum holotype, 1.65 - 1.8 mm (E, F, K), and C. xyloteroides, 3.25 mm (G, H, L).