Chaetocnema salixis Ruan, Konstantinov & Yang

Ruan, Yongying, Konstantinov, Alexander S., Ge, Siqin & Yang, Xingke, 2014, Revision of Chaetocnemasemicoerulea species-group (Coleoptera, Chrysomelidae, Galerucinae, Alticini) in China, with descriptions of three new species, ZooKeys 463, pp. 57-74 : 63-64

Taxon classification Animalia Coleoptera Chrysomelidae

Chaetocnema salixis Ruan, Konstantinov & Yang sp. n. Figure 3

Etymology.

This species is named after the host plant.

Host plants.

Salix sp.

Distribution.

China: Shannxi, Gansu, Sichuang.

Diagnosis.

Chaetocnema salixis resembles Chaetocnema transbaicalica . It can be differentiated from the latter by the following characters: frontolateral angle of pronotum long and sharp laterally; both longitudinal groove and transverse wrinkles on ventral surface of median lobe absent; metatibial serration proximal to large lateral denticle absent or obscure.

Description.

Body length: 2.10-2.50 mm, without head: 1.9-2.30 mm. Female body length: 2.30-2.50 mm, without head: 2.10-2.30 mm. Length of antenna to length of body: 0.60. Body width: 1.13-1.17 mm. Elytron length (along suture) to width (maximum): 2.70-2.75. Pronotum width (at base) to length: 1.74-1.79. Length of elytron to length of pronotum (along middle): 3.47-3.49. Width of elytra at base (in middle of humeral calli) to width of pronotum at base: 1.16-1.19. Maximum width of elytra to maximum width of pronotum: 1.44-1.47.

Color of elytron differs from color of pronotum. Elytra black, without metallic lustre. Pronotum and head bronzish. Antennomere 1 partly dark brown. Antennomeres 2-3 partly brown or completely yellow. Antennomere 4 brown. The remaining antennomeres black. Tibia and tarsi partly brown. Femora brown.

Head hypognathous. Frontal ridge between antennal sockets narrow and convex. Frontolateral sulcus present. Suprafrontal sulcus deep laterally, absent in middle. Orbital sulcus deep. Ratio of width of frontal ridge (excluding margin) to width of antennal socket (excluding margin): 1.20-1.25. Width of frontolateral sulcus to width of antennal socket: 0.29-0.38. Width of orbital sulcus to width of frontolateral sulcus: 0.72. Numbers of punctures on vertex next to each eye: 7-9. Numbers of punctures on orbit: 2. Numbers of hairs along frontolateral sulcus: 9-11. Numbers of hairs on front (triangle area surrounded by frontolateral sulcus and clypeus): 0. Numbers of hairs on clypeus: 8. Numbers of hairs on labrum: 6. Anterior margin of labrum slightly concave in middle.

Base of pronotum with two obscure longitudinal impressions visible only near basal margin. Deep row of large punctures at base of pronotum present on sides, lacking in middle. Pronotal base slightly expanded in middle. Lateral sides of pronotum slightly convex with maximum width near base. Anterolateral prothoracic callosity protruding laterally, forming a sharp angle laterally (Fig. 3: B2). Posterolateral prothoracic callosity poorly developed. Diameter of pronotal punctures 2 to 4 times smaller than distance between them.

Elytra with convex sides. All rows of punctures regular. Elytral humeral callus well developed. Interspace between stria of punctures smooth and glabrous. Numbers of stria of minute punctures on each interspace: 2.

First male protarsomere slightly larger than second one. First male protarsomere, length to width ratio: 1.74-1.78. First and second male protarsomeres, length to length ratio: 1.60-1.80. First and second male protarsomeres, width to width ratio: 1.04-1.20. First male protarsomere, width at apex to width at base: 1.50-1.53. Length of metatibia to distance between denticle and metatibial apex: 2.28-2.36. Large lateral denticle on metatibia sharp. Metatibial serration proximal to large lateral denticle absent or obscure. First male metatarsomere, length to width ratio: 2.80-3.40. First and second male metatarsomeres, length to length ratio: 2.03-2.15. First and second male metatarsomeres, width to width ratio: 0.87-0.97. Third and fourth male metatarsomeres, length to length ratio: 0.52-0.55.

Apical part of median lobe in ventral view narrowing gradually with polygonal line on sides. Ventral longitudinal groove absent. Apical denticle in ventral view absent. Minute transverse wrinkles on ventral side absent. Median lobe in lateral view evenly and strongly curved, slightly sinusoidal near apex. Maximal curvature of median lobe in lateral view situated medially.

Spermathecal receptacle pear-shaped. Basal part of spermatheca duct straight. Spermathecal pump much shorter than receptacle. Apex of spermathecal pump cylin drical or pointed. Spermathecal pump attached to middle of receptacle top. Basal part of receptacle about as wide as apical. Posterior sclerotization of tignum spoon-shaped, wider than mid section. Mid section of tignum nearly straight. Anterior sclerotization of tignum about as wide as mid section. Apex of vaginal palpus subdeltoid, with lateral side slightly arching. Sides of mid part of vaginal palpus (before apex) narrowing from base, slightly widening towards apex. Anterior sclerotization of vaginal palpus nearly parallel. Anterior end of anterior sclerotization broadly rounded. Length of posterior sclerotization greater than width. Width of posterior sclerotization smaller than width of anterior sclerotization.

Type material.

Holotype: 1♂, Yangxian, Qinling Mountains, Shannxi, alt.1700m, VII.2013, Leg.Yongying Ruan, host: Salix sp. " Chaetocnema salixis sp. n., Des. Ruan, Konstantinov, Yang. 2014" (IZCAS).

Paratypes (all in IZCAS, except those that are indicated as USNM): 2♂4♀, Qinling Mountain, Shannxi, VII–VIII.2013, Leg. Yongying Ruan, host: Salix sp.; 3♂ 4♀ same label except Leg. A. Konstantinov (USNM); 1♂2♀, Shatang forestry station, Zhouqu, Gansu, alt.2400m, 5-27.VII.1998, Leg. Shuyong Wang et al.; 1♀, Bifenggou, Bikou, Wenxian, Gansu, 25.VII.1998, alt.2360m, Leg. Xingke Yang; 1♀, Daheba, Tanchang, Gansu, 5.VII.1998, alt.1700-2350m, Leg. Shuyong Wang; 4♀, Miyaluo, Lixian, Sichuang, alt.2780-3300m, 7.VII.1963, Leg. Xuezhong Zhang; 19♂48♀, Sanshenggou, Wolong, Sichuang, alt.2500-2700m, 6-8.VIII.1983, Leg. Shuyong Wang.