Chaetocnema (Chaetocnema) constricta Ruan, Konstantinov & Yang

Ruan, Yongying, Konstantinov, Alexander S., Ge, Siqin & Yang, Xingke, 2014, Revision of the Chaetocnema picipes species-group (Coleoptera, Chrysomelidae, Galerucinae, Alticini) in China, with descriptions of three new species, ZooKeys 387, pp. 11-32 : 23-25

Chaetocnema (Chaetocnema) constricta Ruan, Konstantinov & Yang sp. n. Fig. 4

Etymology.

The name of this species is based on a tiny and tight beetle body.

Distribution.

Anhui, Sichuan, Chongqing, Guizhou, Zhejiang, Jiangsu, Jiangxi, Fujian, Yunnan, Guangxi.

Host plants.

Rubus corchorifolius Linn. f. ( Rosaceae ), Rubus fruticosus Linn., Polygonum sp. ( Polygonaceae ).

Diagnosis.

Body of Chaetocnema constricta sp. n. usually tiny and narrow. It can be differentiated from Chaetocnema picipes , Chaetocnema fortecostata sp. n. and Chaetocnema cheni sp. n. by the following characters: first male protarsomere only slightly larger than second, appendages light in color, anterolateral angles of pronotum obtuse and thickened. Exteriorly this species resembles Chaetocnema kingpinensis . But Chaetocnema kingpinensis is larger in body size, having longer appendages and pronotum (relative to body length). If viewed under a soft light, Chaetocnema constricta 's body is entirely bronzish, while Chaetocnema kingpinensis has usually bronzish pronotum and blackish brown elytra.

Description.

MBL = 1.71-1.80 mm; MBH = 1.52-1.65 mm; FBL = 2.15-2.31 mm; FBH = 1.88-2.16 mm; AL/BL = 0.61-0.62; MBW = 0.90-0.94; EL/EW = 1.28 ± 0.05; PW/PL = 1.44 ± 0.05; EL/PL = 2.55 ± 0.05; EWB/PWB = 1.13 ± 0.05; EWM/PWM = 1.37 ± 0.05.

Elytra bronzish, exactly same color as pronotum. Head dorsally bronzish. Antennomere 1 partly dark brown. Antennomeres 2-4 yellow. Antennomeres 5-6 yellow with brown apex. Remaining antennomeres brown with yellow base. Pro- and meso- femora brown with yellow apex. Metafemora brown. Tibia mostly yellow, dark at distal half. Tarsi yellow.

Head hypognathous. Frontal ridge between antennal sockets narrow and convex. Frontolateral sulcus present. Suprafrontal sulcus shallow and faint or deep laterally, shallow in middle. Suprafrontal sulcus slightly concave. Orbital sulcus (above the antennal socket) very deep. Orbital sulcus forming an obvious narrow deep concave above orbit. Width of frontal ridge to width of antennal socket: 0.70-0.75. Width of orbital sulcus (above antennal socket) to width of frontolateral sulcus: 1.20-1.45. Surface of vertex sparsely and unevenly covered with 5-6 punctures on each side close to eye. Numbers of punctures on orbit on each side: 1-2. Numbers of setae along frontolateral sulcus on each side: 9-10. Numbers of setae on frons (triangular area surrounded by frontolateral sulci and clypeus): 0. Numbers of setae on clypeus: 4. Numbers of setae on labrum: 6. Anterior margin of labrum slightly concave in middle.

Base of pronotum with two short longitudinal impressions visible only near basal margin. Longitudinal impressions lack punctures. Deep row of large punctures at base of pronotum present on sides, lacking in middle. Pronotal base evenly convex. Anterolateral prothoracic callosity has finely developed blunt angle protruding antero-laterally. Posterolateral prothoracic callosity projects beyond lateral margin of pronotum. Diameter of pronotal punctures subequal to distance between them.

Elytra with convex sides. Scutellar row of punctures regular and single. Remaining rows regular. Elytral humeral calli well developed. Interspaces of rows of punctures smooth and glabrous. Two lines of minute punctures on each interspace.

First male protarsomere slightly larger than second. First male protarsomere, length to width ratio: 1.90-2.00. First and second male protarsomeres, length to length ratio: 1.60-1.80, width to width ratio: 1.05-1.13. First male protarsomere, width at apex to width at base: 1.70-1.88. Length of metatibia to distance between denticle and metatibial apex: 2.88-3.04. Large lateral denticle on metatibia sharp. Metatibial serration proximal to large lateral denticle present, obtuse. Metatibia proximate to denticle in dorsal view concave. First male metatarsomere, length to width ratio: 1.86-1.91. First and second male metatarsomeres, length to length ratio: 1.91-1.93, width to width ratio: 0.95-1.07. Third and fourth male metatarsomeres, length to length ratio: 0.59-0.76. Metatibia length to metafemora length: 0.82 ± 0.05. Length of hind leg to length of body: 0.91 ± 0.05.

Apical third of median lobe of aedeagus parallel-sided. Apical part of median lobe in ventral view narrowed abruptly and forms big cap on top. Ventral longitudinal groove of median lobe poorly developed, with obtuse margins. Apical part of longitudinal groove as wide as basal. Middle part of longitudinal groove narrower than basal. Apical denticle of aedeagus in ventral view absent. Minute transverse wrinkles on ventral side of median lobe absent. Median lobe in lateral view sinusoidal near apex. Maximal curvature of median lobe in lateral view situated medially. Median lobe thickened in lateral view. Width (in middle) to length of median lobe (ventral view): 0.17.

Spermathecal receptacle pear-shaped and cylindrical. Spermathecal pump much shorter than receptacle. Apex of spermathecal pump cylindrical. Spermathecal pump attached to middle of receptacle top. Basal part of receptacle about as wide as middle and apical parts separately. Posterior sclerotization of tignum spoon-shaped, wider than mid section. Apex of vaginal palpus subdeltoid, with lateral side slightly arching. Sides of mid part of vaginal palpus slightly narrowing from base, and slightly widening towards apex. Anterior sclerotization of vaginal palpus slightly narrowing anteriorly. Anterior end of anterior sclerotization narrowlly rounded. Length of posterior sclerotization greater than width. Posterior sclerotization about as wide as anterior sclerotization.

Type materials

(all the materials preserved in IZCAS). Holotype: 1♂ (Fig. 4: A), Shuyang, Fuan, Fujian, alt.200m, 2013.VIII.12, leg. Yongying Ruan. Paratypes: 30♀20♂, Huangshan, Anhui, alt.630m, 18.VIII.1978, leg. Shuyong Wang; 6♀7♂, Shaping, Sichuan, 29.XI; 6♀6♂, Ebian, Sichuan, X; 1♀, Beibei, Chongqing, 11.VI.1940; 6♀3♂, Huaxi Guizhou, 8.VI.1980; 6♀1♂, Sanmuping, Tianmu Mountain, Zhejiang, 30.VII.1998, leg. Hong Wu; 2♀, Tianmu Mountain, Zhejiang, 6.VI.1999, leg. Mingyuan Gao; 3♀1♂, Longwang Mountain, Anji, Zhejiang, 1995-1996, leg. Hong Wu; 1♂, Nanjing, Jiangsu, 1994, leg. Miao Hu; 20♀8♂, Jiulianshan, Jiangxi, 20-23.IX.1978, leg. Peiyu Yu, feed on Rubus sp.; 1♂2♀, Dazhulan, Fujian, 15-20.VI.1948; 5♀, Wuyi Mountain, Fujian, alt.500-1100m, V.1997, leg. Jiashe Wang; 1♀, Wuyi Mountain, Fujian, alt.1200m, 1997.VII, leg. Jiashe Wang; 83♀30♂, Wuyi Mountain, Fujian, 5-26.V.1997, leg. Jiashe Wang; 1♀2♂, Nanping, Fujian, 22.VII.1957, leg. Jiashe Wang; 1♂, Aotou, Huangkeng, Jianyang, Fujian, alt.750-950m, 3.VI.1997, leg.Yong Zuo; 1♀, Longling, Yunnan, alt.1600m, 20.V.1995, leg. Zifeng Xue; 1♂, Fangcheng, Guangxi, alt.650m, 14.III.1998, leg. Gexia Qiao; 10♀8♂, Jinxiu, Guangxi, alt.600m, V.1999, leg. Mingyuan Gao; 5♀2♂, Yanshan, Guilin, Guangxi, 15.VI.1963. leg. Shuyong Wang; 1♂, Tianping Mountain, Longsheng, Guangxi, 9.VI.1963, leg. Shuyong Wang; 17♀10♂, Yaoshan, Xiuren, Guangxi, 6.V.1938.