Pelenomus waltoni (Boheman, 1843)

Yang, Lujing, Huang, Junhao, Zhang, Runzhi & Wu, Hong, 2013, A review of the genus Pelenomus Thomson (Coleoptera: Curculionidae: Ceutorhynchinae) from China, Zootaxa 3652 (4), pp. 401-423 : 402-404

Pelenomus waltoni (Boheman, 1843)

( Figs. 1–4 , 21–24, 41–48, 88)

Description. Male. LB: 2.16–2.20 mm (mean, 2.18 mm); LR: 0.52–0.59 mm (0.56 mm); WP: 0.78–0.83 mm (0.81 mm); LP: 0.48–0.53 mm (0.50 mm); WE: 1.28–1.34 mm (1.31 mm); LE: 1.28–1.47 mm (1.38 mm). N = 3 for all measurements. Body dark brown in general, antennae and leg yellowish-brown, eyes reddish, Head and pronotum yellowish-brown, elytral suture blackish. Habitus as shown in Figs. 1 and 2 .

Vestiture thick. Head (Figs. 21–22) covered with dense brown hairlike scales on disc and dense white oval scales behind eyes; rostrum generally with dense yellow hairlike scales. Pronotum ( Fig. 1 ) with brown linear scales on disc, and with oval white scales on basal part and lateral sides. Elytra ( Fig. 1 ) generally covered with dark brown linear scales, interrupted by dense patches of white oval scales on intervals I–V more sporadic on other intervals. Underside ( Figs. 2–3 ) densely covered with oval white scales. Legs ( Fig. 2 ) moderately densely clothed with white oval scales on femora and linear scales on tibiae. Pygidium ( Fig. 4 ) with dense dark brown hairlike scales on disc and white lanceolate scales along the margin.

Rostrum slender, 1.00–1.19 times longer than the pronotum. In dorsal view (Fig. 21), rostrum straight and almost parallel-sided, not widened at apex; dorsal surface without median carina nor sulcus, with shallow elongate medium-sized punctures on each side, forming two-three lines of ill-defined wrinkles; apical part of rostrum smooth, shining, with sparse fine punctures. In lateral view (Fig. 22), rostrum slightly curved at the antennal insertion, dorsal outline slightly more steeply curved than the ventral. Frons as wide as the base of rostrum, not widened basally; frons and vertex uniformly covered with shallow medium-sized punctures. Antennae inserted at apical 1/3 of rostrum, with scape 0.90 times as long as the funicle, length ratio of funicular segments I: II: III: IV: V: VI = 3.80: 2.28: 1.20: 1.28: 1.32: 1.00 and width ratio = 1.84: 1.00: 1.12: 1.24: 1.24: 1.40.

Pronotum ( Fig. 1 ) 1.53–1.74 times wider than long, 0.34–0.40 times as long as and 0.61–0.63 times as wide as elytra, bearing a pair of sharp tubercles at the middle of lateral sides. Dorsum with shallow median suture, punctures deep and large in the basal part and relatively smaller along lateral margin; basal margin not serrate; apical margin moderately raised. Sides nearly straight, widest at middle, weakly converging toward the subapical constriction. Scutellum subovate.

Elytra ( Fig. 1 ) oval, 1.00–1.13 times longer than wide, 2.51–2.92 times longer and 1.60–1.64 times wider than pronotum; widest at humeri, sides subparallel, then moderately convergent toward subapical calli. Intervals moderately flattened, slightly wider than striae, each with 3–4 rows of large and acute squamate granules; striae relatively broad and shallow, with distinct punctures.

Legs ( Fig. 2 ) slender, procoxae separated by a distance about as wide as basal width of rostrum; middle coxae separated by a distance hardly wider than apical width of rostrum. Femora clavate, without tooth; middle and hind femora more inflated than front femora; middle tibiae with sharp mucro; tarsi moderate in length; claws free, slender, not appendiculate.

Prosternum simple, without prosternal canal. Venter ( Fig. 3 ) coarsely and moderately punctured; ventrite I shallowly concave on disc; ventrite V simple, without concavity nor denticles; length ratio of ventrites I: II: III: IV: V = 6.50: 3.84: 1.00: 1.06: 2.21 and width ratio =1.77: 1.56: 1.40: 1.23: 1.00.

Pygidium ( Fig. 4 ) narrow at the basal margin, 1.51 times wider than long. Sternite IX ( Fig. 45 ) with spiculum gastrale as long as the aedeagal body and longer than its apodeme, bent leftward. Tegmen ( Fig. 44 ) with apodeme short and slender, nearly half as long as diameter of tegminal ring, gradually narrowed basally, truncate at base. Aedeagal body ( Figs. 41–43 ) broad, relatively thin and straight in profile, and hardly curved at apex; sides weakly narrowed from the base to the middle, slightly broadened to apical fourth, then gradually convergent apically; apical projection rounded at apex. Endophallus ( Fig. 41 ) with a pair of reniform sclerites near the base, and dense longitudinal dentiform spicules in median part.

Female. LB: 2.16–2.36 mm (mean, 2.52 mm); LR: 0.61–0.71 mm (0.68 mm); WP: 0.81–0.86 mm (0.84 mm); LP: 0.53–0.56 mm (0.55 mm); WE: 1.37–1.43 mm (1.39 mm); LE: 1.36–1.66 mm (1.49 mm). N = 3 for all measurements.

Rostrum (Figs. 23–24) longer than pronotum, 1.10–1.33 times longer than pronotum. Frons as wide as the base of rostrum, gradually widened basally. Pronotum 1.53–1.56 times wider than long. Elytra 0.99–1.16 times longer than wide. Tibiae not mucronate. Ventrites I and II moderately inflated and punctured; ventrite V slightly inflated without concavity.

Pygidium 1.21 times wider than long. Sternite VIII ( Fig. 46 ) with several minute setae near the apex; arms very wide, 1.8 times longer than apodemes, nearly as long as coxite and stylus combined, widely separated, with inner margins shallowly arcuate and gradually broadened apically, with outer margins broadly arcuate; apodemes short and slender. Coxites ( Fig. 47 ) robust, nearly four times longer than styli; styli apicolaterally inserted, moderate in length, nearly two times longer than wide. Spermatheca ( Fig. 48 ) with cornu robust, strongly curved; collum evenly and moderately convex; ramus strongly marked; insertions of the duct and gland close to each other. Otherwise practically as in male.

Distribution. China (Hubei, Heilongjiang— new record; Fig. 88 ), Eurasia (Colonnelli, 2004).

Specimens examined. HUBEI. 6 males and 3 females, Tongcheng, Mt. Tongboshan, 1600 m, IX-2003, Li (NIAES). HEILONGJIANG. Yichun, Wuying, Fenglin: 4 males and 4 females, 20-VII-2008, J. Huang; 1 female, 21-VII-2008, J. Huang, on Polygonum spp.; 6 males and 3 females, 24-VII-2008, J. Huang; Shangzhi, Mt. Mao’ershan, 1 male, 28-VII-2008, S. Zhang. (ZAFU).

Biological notes. On Polygonum hydropiper L., P. m i te Schrank (Wagner, 1939).

Remarks. This species is a new record to China. It can be easily distinguished from other Chinese Pelenomus from its slenderer rostrum longer than pronotum, and ventrite V in male without concavity, while the other species have stouter rostrum shorter than pronotum and ventrite V slightly concave. With its thick vestiture and slender rostrum, the species is somewhat similar to members of Phytobius .

Figures

FIGURE 88. Geographic distribution of the genus Pelenomus in China.

FIGURES 1 – 4. Pelenomus waltoni, male. (1) Dorsal habitus. (2) Lateral Habitus. (3) Venter. (4). Pygidium. Scale bar: 0.50 mm for 1 – 3; 0.25 mm for 4.

FIGURES 41 – 48. Male and female genitalia of Pelenomus waltoni from Heilongjiang, China. (41 – 45) Male. (41) Aedeagus, dorsal view. (42) Apex of the aedeagal body, dorsal view. (43) Aedeagus, lateral view. (44) Tegmen. (45) Sternites IX. (46 – 48) Female. (46) Sternite VIII. (47) Coxite and stylus. (48) Spermatheca. Scale bar: 0.20 mm for 41 – 46, 0.10 mm for 47 – 48.