Pelenomus quadricorniger (Colonnelli, 1986)

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 : 407-409

Pelenomus quadricorniger (Colonnelli, 1986)

( Figs. 9–12 , 29–32, 57–64, 82–83, 88)

Description. Male. LB: 2.47–2.61 mm (mean, 2.54 mm); LR: 0.47–0.52 mm (0.49 mm); WP: 0.92–0.96 mm (0.95 mm); LP: 0.64–0.67 mm (0.65 mm); WE: 1.58–1.61 mm (1.59 mm); LE: 1.65–1.76 mm (1.72 mm). N = 3 for all measurements.

Body black; head, pronotum and elytra black; eyes yellowish-brown; antennae and legs reddish-brown. Habitus as shown in Figs. 9 and 10 .

Vestiture fine. Head (Figs. 29–30) covered with sparse brown hairlike scales on disc and sparse white oval scales behind eyes; rostrum with dense brown hairlike scales. Pronotum ( Fig. 9 ) with brown linear scales, and with white oval scales in basal part and lateral sides. Elytra ( Fig. 9 ) covered with scutellar spot formed of white oval scales; intervals bearing 3–4 rows of dark brown linear scales; striae bearing a fine hairlike scale in each puncture. Underside of body ( Figs. 10–11 ) covered with white oval scales. Legs ( Fig. 10 ) moderately clothed with dense white linear scales. Pygidium ( Fig. 12 ) with dense dark brown hairlike scales.

Rostrum robust, 0.73–0.81 times longer than the pronotum. In dorsal view (Fig. 29), rostrum slightly widened basally, almost parallel-sided in basal 1/2, and broadest 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. 30) rostrum slightly curved; dorsal outline curved as the ventral one. Frons clearly narrower than the base of rostrum, then gradually widened basally; frons and vertex uniformly covered with shallow medium-sized punctures. Antennae with scape 0.73 times as long as the funicle, length ratio of funicular segments I: II: III: IV: V: VI = 4.58: 3.46: 1.96: 1.46: 1.17: 1.00 and width ratio = 1.88: 1.04: 1.13: 1.00: 1.29: 1.46.

Pronotum ( Fig. 9 ) 0.37–0.39 times as long and 0.59–0.61 times as wide as elytra, 1.39–1.49 times wider than long, bearing a pair of sharp tubercles in the middle of the lateral sides. Dorsum deeply punctured, and with shallow median suture; basal margin serrate; apical margin moderately raised. Sides nearly straight, widest at middle, sharply converging toward the subapical constriction. Scutellum subovate.

Elytra ( Fig. 9 ) heart-shaped, 2.55–2.61 times longer and 1.63–1.72 times wider than pronotum, 1.05–1.10 times longer than wide; widest at humeri, subparallel in basal 2/3, then moderately convergent toward subapical calli. Intervals moderately convex, nearly two times wider than striae, almost all of the same width and height, each with 3–4 rows of large and acute squamate granules; striae moderately marked, relatively wide and deep, with distinct punctures.

Legs ( Fig. 10 ) slender, procoxae separated by about the same width of basal rostrum; middle coxae separated by a distance equal to the 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 appendiculate, inner branches separate.

Prosternum simple, without prosternal canal. Venter ( Fig. 11 ) coarsely and moderately densely punctured; ventrite I weakly concave on disc; ventrite V slightly concave along the apical margin; length ratio of ventrites I: II: III: IV: V = 6.15: 3.22: 1.33: 1.00: 2.17 and width ratio = 1.89: 1.59: 1.35: 1.21: 1.00.

Pygidium ( Fig. 12 ) 1.17 times wider than long, finely punctured. Sternite IX ( Fig. 61 ) with spiculum gastrale slightly longer than aedeagal body or its apodeme, bent leftward. Tegmen ( Fig. 60 ) with apodeme relatively slender, nearly half as long as diameter of tegminal ring, subparallel along entire length, rounded and weakly broadened at base. Aedeagal body ( Figs. 57–59 ) slender, moderately curved upward in the apical fourth; sides subparallel in the basal 5/6, then gradually convergent apically; apical projection rounded at apex. Endophallus ( Fig. 57 ) with sparse longitudinal dentiform spicules near the base, and a dentiform spiculate field in the middle. Female. LB: 2.67–2.77 mm (mean, 2.72 mm); LR: 0.53–0.57 mm (0.56 mm); WP: 0.86–1.12 mm (1.00 mm); LP: 0.52–0.80 mm (0.66 mm); WE: 1.68–1.79 mm (1.73 mm); LE: 1.70–1.90 mm (1.83 mm). N = 3 for all measurements.

Rostrum (Figs. 31–32) relatively short, 0.87–1.10 times longer than the pronotum. Pronotum 1.54–1.66 times wider than long. Elytra 0.99–1.13 times longer than wide. Abdomen more convex and tibiae without mucro. Ventrite V slightly inflated without concavity.

Pygidium 1.28 times wider than long. Sternite VIII ( Fig. 62 ) with dense minute setae near the apex; arms very wide, three times longer than apodemes, nearly as long as coxite and stylus combined, widely separated, with inner margins strongly arcuate and gradually broadened apically, with outer margins broadly arcuate; apodemes short and slender. Coxites ( Fig. 63 ) robust, 1.5 times wider than long, nearly 3.5 times longer than styli; styli apicolaterally inserted, moderate in length, nearly three times longer than wide. Spermatheca ( Fig. 64 ) with cornu robust, strongly curved; collum evenly and moderately convex; ramus weakly marked; insertions of the duct and gland close to each other. Otherwise practically as in male.

Distribution. China (Fujian, Guizhou– new record; Fig. 88 ), Eurasia (Colonnelli, 2004).

Specimens examined. FUJIAN. Jiangle, Mt. Longqishan: 1 male, 700 m, 20-VIII-1991, X. Zhang, IOZ(E) 895283; 3 females, 500 m, Wujiu, 13-VIII-1991, X. Zhang, IOZ(E) 895633, 895634, 895295; 1 male, 27-V-1991, J. Yao, IOZ(E) 895288; 1 male, 25-V-1991, R. Zhang, IOZ(E) 895307; 1 female, Lishan, 650 m, 17-VIII-1991, X. Zhang, IOZ(E) 895310(IZCAS). Mt. Wuyishan: 1 female, Tongmuguan, Guanping, 850–1000 m, 13-VIII-1990, S. Jiang, IOZ(E) 894794(IZCAS). 1 female, Xingcun, Sangang, 720 m, 13-VI-1990, Y. Zuo, IOZ (E) 894581(IZCAS). 1 male, Xingcun, Sangang, 740 m, 30-VI-1960, Y. Zhang, IOZ(E) 895647(IZCAS). 1 male, Shaowu, 3-VI-1965, IOZ(E) 895649; Shaowu, Wuku: 1 female, 23-VI-1965, IOZ(E) 895636; 1 female, 24-VI- 1965, IOZ(E) 895635; 1 male, 24-VI-1965, IOZ(E) 895641; 1 male, 1-VI-1965, IOZ(E) 895638; 1 male, Shaowu, Tieyang, 13-VI-1965, IOZ(E) 895639(IZCAS). Jianyang, Sanxia: 1 female, 28-VI-1965, IOZ(E) 895645; 3 males, 29-VI-1965, IOZ(E) 895642–895644; 1 female, 29-VI-1965, IOZ(E) 895640(IZCAS). 1 male, Jianyang, Huangkeng, Changba, 340–440 m, 17-V-1960, IOZ(E)895648(IZCAS). GUIZHOU. 1 male, Leishan, Yaojiang, 870–1100 m, 5-VII-1988, S. Wang, IOZ(E)895646(IZCAS).

Biological notes. On Polygonum amphibium L., P. lapathifolium L., P. m i te Schrank (Colonnelli, 2004). Adults were collected on Polygonum spp. in moist places and near aquatic habitats, where the larva feeds on the leaves of these plants on which it fixes a cocoon built before pupation (Caldara and O’Brien, 1995). In August, 2012, several adults were collected in an aquatic habitat in Mt. Longqishan, Fujian, while feeding on the vine Polygonum hastato-sagittatum Mak. ( Figs. 82–83 ), together with a number of individuals of P. ro e l o f s i. The vine is quite common in many sites in Mt. Longqishan, including both aquatic and semiaquatic habitats, but the species was collected only on the submerged plants, which might be a necessary condition for its colonization.

Remarks. This species is new to China. It is closely related to P. ro e l o f s i and P. curvatus according to the main external features, such as black body, elytra covered with fine brown linear scales and ventrite V with a small median concavity in male. P. quadricorniger can be rather easily differentiated from the above two species by its body comparatively larger and only its middle tibiae mucronate, whereas P. ro e l o f s i and P. curvatus each have a smaller body and mucros on both middle and hind tibiae.

Figures

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

FIGURES 9 – 12. Pelenomus quadricorniger, male. (9) Dorsal habitus. (10) Lateral Habitus. (11) Venter. (12). Pygidium. Scale bar: 0.50 mm for 9 – 11; 0.25 mm for 12.

FIGURES 57 – 64. Male and female genitalia of Pelenomus quadricorniger from Fujian, China. (57 – 61) Male. (57) Aedeagus, dorsal view. (58) Apex of the aedeagal body, dorsal view. (59) Aedeagus, lateral view. (60) Tegmen. (61) Sternites IX. (62 – 64) Female. (62) Sternite VIII. (63) Coxite and stylus. (64) Spermatheca. Scale bar: 0.20 mm for 57 – 62, 0.10 mm for 63 – 64.

FIGURES 82 – 87. (82 – 83) Pelenomus quadricorniger. (82) Adult food plant, Polygonum hastato-sagittatum Mak. (83) Habitat in Shipaichang, Mt. Longqishan, Jiangle, Fujian, China. (84 – 85) Pelenomus roelofsi. (84) Adult food plant, Polygonum muricatum Meisn. (85) Habitat in Yujiaping, Mt. Longqishan, Jiangle, Fujian, China. (86 – 87) Pelenomus curvatus sp. nov. (86) Adult food plant, Polygonum thunbergii Sieb. et Zucc. (87) Habitat in Dahaoping, Mangbang, Tengchong, Yunnan, China.