Chaetocnema (Chaetocnema) fortecostata Chen, 1939

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 : 16-19

Chaetocnema (Chaetocnema) fortecostata Chen, 1939 Fig. 2

Chaetocnema fortecostata Chen, 1939: 33 (type locality: “Beibei” Guanxi, China; type depository: IZCAS; lectotype designated here); Heikertinger 1951: 207.

Distribution.

Shaanxi, Hubei, Chongqing, Sichuan, Zhejiang, Hunan, Jiangxi, Fujian, Yunnan, Guangxi.

Host plants.

Polygonum sp. ( Polygonaceae ).

Diagnosis.

Chaetocnema fortecostata sp. n. is similar to Chaetocnema picipes and Chaetocnema cheni sp. n. But the aedeagus in lateral view is robust in Chaetocnema fortecostata and slender in Chaetocnema picipes and Chaetocnema cheni . Chaetocnema fortecostata have bronzish dorsal surface of its body, while Chaetocnema picipes and Chaetocnema cheni are copperish.

Description.

MBL = 1.75-1.90 mm; MBH = 1.60-1.79 mm; FBL = 2.03-2.12 mm; FBH = 1.89-2.03 mm; AL/BL = 0.64 ± 0.05; MBW = 0.95-1.08 mm; EL/EW = 2.64 ± 0.05; PW/PL =1.62 ± 0.05; EL/PL = 2.98 ± 0.05; EWB/PWB = 1.07-1.19; EWM/PWM = 1.34 ± 0.05.

Color of dorsal side of body bronzish throughout, including head. Antennomere 1 partly dark brown. Antennomeres 2-3 yellow. Antennomere 4 yellow or partly brown. Antennomere 5 partly brown. Remaining antennomeres black. Pro- and mesofemora brown with yellow on apex. Metafemora brown. Tarsi brown with yellow on base of each tarsomere.

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 antennal socket) obscure and narrow. Width of frontal ridge to width of antennal socket: 0.56-0.66. Width of orbital sulcus to width of frontolateral sulcus: 0.71 ± 0.05. Surface of vertex sparsely and unevenly covered with 5-6 punctures near each eye. Numbers of punctures on orbit: 1-2 on each side. Numbers of setae along frontolateral sulcus: 5-6 on each side. Numbers of setae on frons (triangular area surrounded by frontolateral sulcus and clypeus): 0. Numbers of setae on clypeus: 5. Numbers of setae on labrum: 6. Anterior margin of labrum slightly convex in middle.

Base of pronotum with two short, obscure longitudinal impressions without punctures near basal margin. Deep row of large punctures at base of pronotum present on sides, lacking in middle. Shape of pronotal base evenly convex. Lateral sides of pronotum slightly convex with maximum width near base. Anterolateral prothoracic callosity protruding laterally forming strong round angle. Posterolateral prothoracic callosity projects up to lateral margin of pronotum. Diameter of pronotal punctures 2 to 4 times smaller than distance between them.

Elytra with convex sides. Scutellar row of punctures regular and single. Remaining rows regular. Elytral humeral calli well developed. Interspace smooth and glabrous. 2 lines of minute punctures on each interspace.

First male protarsomere, length to width ratio: 1.65 ± 0.05. First and second male protarsomeres, length to length ratio: 1.94-2.24, width to width ratio: 1.42-1.45. First male protarsomere, width at apex to width at base: 1.60-1.75. Length of metatibia to distance between denticle and metatibial apex: 2.80-2.90. Large lateral denticle on metatibia sharp. Metatibial serration proximal to large lateral denticle present, obtuse. Metatibia proximad to denticle in dorsal view concave. First male metatarsomere, length to width ratio: 3.60-3.67. First and second male metatarsomeres, length to length ratio: 1.87-1.93, width to width ratio: 0.83. Third and fourth male metatarsomeres, length to length ratio: 0.60-0.65. Metatibia length to metafemora length: 0.76 ± 0.05. Length of hind leg to length of body: 0.87 ± 0.05.

Median lobe of aedeagus quite robust and thickened in lateral view. Apical third of median lobe widening evenly. Apical part of median lobe in ventral view narrowing abruptly. Ventral longitudinal groove of median lobe absent in apical part and poorly developed in middle and basal part. Apical denticle of aedeagus in ventral view poorly differentiated, curved ventrally in lateral view. Minute transverse wrinkles on ventral side of median lobe absent. Median lobe in lateral view slightly sinuous near apex. Maximal curvature of median lobe in lateral view situated medially. Width (in middle) to length of median lobe (in ventral view) about: 0.15.

Spermathecal receptacle pear-shaped. Spermathecal pump much shorter than receptacle. Apex of spermathecal pump cylindrical. Spermathecal pump attached to middle of receptacle top. Maximum width of receptacle situated basally. Basal part of receptacle wider than apical. Posterior sclerotization of tignum spoon-shaped, wider than mid section. Anterior sclerotization of tignum narrower than mid section. Apex of vaginal palpus subdeltoid, with lateral side slightly arching. Sides of mid part of vaginal palpus (before apex) narrowing from base, widening towards apex. Anterior sclerotization of vaginal palpus slightly widening anteriorly. Anterior sclerotization of vaginal palpus slightly and evenly curved along length. Anterior end of anterior sclerotization broadly rounded. Length of posterior sclerotization greater than width. Posterior sclerotization about as wide as anterior.

Type materials

(preserved in IZCAS). Lectotype (designated here): 1♂, (1) Yangshuo, 21.VIII.1938, (2) Lectotype, Chaetocnema fortecostata Chen, 1939, des. Yongying Ruan et al.

Paralectotypes (designated here): 2♂5♀, (1) Yangshuo, 21.VIII.1938, (2) Paralectotype, Chaetocnema fortecostata Chen, 1939, des. Yongying Ruan et al.

Materials

(all the materials preserved in IZCAS). 19♀14♂, Huoditang, Qinling Mountain, Shaanxi, alt.1600m, 6.VI.2013, leg. Yongying Ruan, feed on Polygonum sp.; 3, Maoping, Yangxian, Qinling Mountain, Shaanxi, alt.701m, 10.VI.2013, leg. Yongying Ruan; 2♂, Longmen River, Xingshan, Hubei, alt.1300m, leg. Shimei Song; 6, Longmen River, Xingshan, Hubei, 8.IX.1994, alt.1300m, leg. Jian Yao, feed on Polygonum sp.; 1♀2♂, Sanxia Linchang, Badong, Hubei, 26.VI.1994, alt.130m, leg. Jian Yao; 2♀1♂, Beibei, Chongqing, 17.V.1941; 3♂, Longchi, Sichuan, IX.29; 1♀2♂, Fengdu, Sichuan, alt.200m, 29.IX.1994, leg. Shimei Song; 56, Wangerbao, Wangxian, Sichuan, alt.1200m, 4.X.1994, leg. Jian Yao; 1♀1♂, Chudian, Emei Mountain, Sichuan, 28.VI.1957, leg. Fuxing Zhu; 1♀, Tienmo Shan, Zhejiang, 20.IX.1953; 24, Shanmuhe, Hunan, alt.600, 14.VIII.1988, leg. Shuyong Wang; 7♀4♂, Xingzi, Jiangxi, 1932; 1♀1♂, Shuyang, Fuan, Fujian, IV.3013, leg. Yongying Ruan, feed on Polygonum sp.; 5♀2♂, Sangxiang, Xingcun, Chongan, Fujian, alt.740m, 7.VI.1960, leg. Yong Zuo; 187, Baijixun, Weixi, Yunnan, alt.1780m, leg. Shuyong Wang, feed on Polygonum sp.; 14♀3♂, Xiaomengyang, Yunnan, alt.900m, III-IV.1957, leg. Shuyong Wang; 1♂, Damenglong, Xishuangbanna, Yunnan, alt.650m, 6.X.1958, leg. Zhizhi Chen.

Remarks.

There is no holotype or paratype in the IZCAS. But we found eight specimens belonging to what looks like a type series of this species labeled as " Chaetocnema fortecostata sp. n." with Chen’s handwriting. The locality on the label corresponds with the original description. Therefore we consider these eight specimens as the syntypes. Here we designate one male as the lectotype and the remaining seven as paralectotypes.

This species only occurs in the Oriental China while the northernmost specimens were found on the southern slopes of Qinling Mountain, which is considered as a border between Palearctic and Oriental Regions within China ( Chen 1997; Yang 2005).