Chaetocnema (Chaetocnema) hongkongensis Ruan & Yang & Konstantinov & Prathapan & Zhang 2019, New Species

19. Chaetocnema (Chaetocnema) hongkongensis Ruan, Konstantinov & Yang, New Species

(Figs. 40, 41)

Etymology: This species is named after the type locality. Specific epithet is a noun in apposition.

Diagnosis: This species is close to C. tonkinensis and C. yiei. It may be differentiated from C. tonkinensis by the shape of aedeagus and lighter body color, and from C. yiei by much smaller body and shape of the aedeagus.

Host plants: Convolvulaceae (probably Ipomoea sp.). All the specimens were collected on the leaves of the host plant (see Fig. 41). Adult feeding results in characteristic winding patterns along the veins of leaves.

Distribution: China, Vietnam, Thailand.

Description: Body length: 1.70–1.80 mm. Body width: 0.98–1.04 mm. Ratio of length of antenna to length of body: 0.63–0.67. Ratio of elytron length (along suture) to width (maximum): 2.35–2.40. Ratio of pronotum width (at base) to length: 1.65–1.70. Ratio of length of elytron to length of pronotum (along middle): 2.62–2.67. Ratio of width of elytra at base (in middle of humeral calli) to width of pronotum at base: 1.01–1.15.

Dorsum coppery brown. Head and pronotum finely reticulated. Antennomeres completely yellow brown, apical ones slightly darker. Tarsi and tibiae bright yellow brown. Pro- and mesofemora yellow brown, slightly darker than tarsi and tibae. Metafemora red brown.

Head hypognathous. Frontal ridge wide and convex. Frontolateral sulcus present. Suprafrontal sulcus shallow and narrow, very slightly convex. Orbital, supraantennal sulci moderetely to poorly developed. Ratio of width of frontal ridge (excluding margin) to width of antennal socket (excluding margin): 1.90–2.10. Number of punctures on vertex: 5–6 on each side near eye. Number of punctures on orbit: 1–2 on each side. Number of punctures on frons (triangular area surrounded by frontolateral sulcus and clypeus): 0. Number of setae on clypeus: approximately 20. Number of setae on labrum: 6. Anterior margin of labrum slightly concave.

Pronotum without longitudinal impressions near basal margin. Deep row of large punctures at base of pronotum present, basal margin of pronotum depressed. Pronotal base evenly convex. Lateral margins of pronotum slightly convex, converging forward. Anterolateral prothoracic callosity weak, slightly truncate. Posterolateral prothoracic callosity poorly developed. Pronotal punctures shallow, longitudinal. Diameter of pronotal punctures 2–3 times smaller than distance between them.

Elytra with slightly convex lateral sides. Elytral punctures conspicuously larger than those of pronotum, arranged in single rows, including peri-scutellar row. Elytral interspaces between puncture rows slightly costate at sides. Number of rows of minute punctures on each interspace: 2–3. Humeral callus well developed.

First male protarsomere slightly larger than second, larger than that of female. Excavation on metatibia moderately deep. Large lateral denticle on metatibia sharp. Metatibial serration proximal to large lateral denticle absent or poorly developed.

Apex of aedeagus in ventral view narrowing gradually. Ventral longitudinal groove absent. Apical denticle in ventral view present, weak, merge with apex of aedeagus. Minute transverse wrinkles on ventral side absent. Aedeagus in lateral view curved at base and almost straight near apex.

Spermathecal receptacle oblong. Spermathecal duct coiled. Spermathecal pump much shorter than receptacle. Apex of spermathecal pump narrowed, pointed. Vaginal palpus slightly narrowing from base till middle, thence approximately parallel sided. Posterior sclerotization longer than wide. Posterior sclerotization as wide as anterior.

Types: Holotype: ♂ (IZCAS), labels: 1) China, Dayu Moutain, Hongkong, 13.IV.2013, leg. Yongying Ruan, host plant: Convolvulaceae; 2) ♂; 3) Holotype; 4) Chaetocnema hongkongensis sp. nov. Des. Yongying Ruan, 2016.

Paratypes: 1♀ (IZCAS), China, Dayu Moutain, Hongkong, 13.IV.2013, leg. Yongying Ruan, Host plant: Pericampylus sp., paratype, Chaetocnema hongkongensis sp. nov. Des. Yongying Ruan, 2016; 2♂ (USNM), China, Lantou Isl., Hongkong, 12.XI.1977, leg. Gary F. Hevel; 11♂ 10♀ (IZCAS), China, Dayu Moutain, Hongkong, 13.IV.2013, leg. Yongying Ruan, Host plant: Pericampylus sp.; 2♂ (IZCAS), China, Honghualing, Hongkong, 14.IV.2013, leg. Yongying Ruan, Host plant: Pericampylus sp. Chaetocnema hongkongensis sp. nov. Des. Yongying Ruan, 2016.

Material: 2♂ 3♀ (IZCAS), China, Guangxi, Yangsuo; 3♂ 2♀ (IZCAS), China, Nanking, 30.VIII.1923, Chaetocnema tonkinensis Chen det. Chen; 3♀ (IZCAS), China, Fujian, Dazhulan, 15.VIII.1948; 2♂ (USNM), Vietnam, Tonkin, Hoa-binh, VII.1939, leg. A. de. Cooman; 1♂ 2♀ (USNM), Thailand (North), Nan, 500m, 31.VIII.1985, J. Reacher & Huber, Chaetocnema tonkinensis Chen det. H. Takizawa.