Chaetocnema (Chaetocnema) melonae Chen, 1934

Ruan, Yongying, Yang, Xingke, Konstantinov, Alexander S., Prathapan, Kaniyarikkal D. & Zhang, Mengna, 2019, Revision of the Oriental Chaetocnema species (Coleoptera, Chrysomelidae, Galerucinae, Alticini), Zootaxa 4699 (1), pp. 1-206 : 75-77

25. Chaetocnema (Chaetocnema) melonae Chen, 1934 (Status Restored)

( Fig. 46 )

Chaetocnema melonae Chen, 1934: 252 . TL: Vietnam ( Tonkin centr.: Env. de Tuyen–Quan). TD: MNHN?? We could not locate the types in MNHN or IZCAS. (This species was previously synonymized with C. duvivieri Jacoby, 1892 in Medvedev, 2001: 613 . Status restored here)

Chaetocnema himalayana Medvedev, 1993: 372 . TL: India. TD: NHMB. (Syn. Nov.)

Distribution: China (Tibet); Vietnam ( Chen, 1934), India ( Medvedev, 1993).

Host plants: Unknown.

Description: Body length 2.90–3.30 mm, body width 1.75–1.95 mm. Ratio of elytron length (along suture) to width (maximum): 2.60–2.70. Ratio of pronotum width (at base) to length: 1.75–1.80. Ratio of length of elytron to length of pronotum (along middle): 2.85–2.95. Ratio of width of elytra at base to width of pronotum at base (in middle of humeral calli): 1.10–1.15. Ratio of maximum width of elytra to maximum width of pronotum: 1.40–1.45.

Dorsum metallic blue.Antennae with antennomeres 4–5 yellow brown, distal 6–7 dark brown. Legs dark brown, with slightly lighter color near femoro-tibial joints.

Head hypognathous. Frontal ridge narrow. Frontolateral sulcus present. Suprafrontal sulcus poorly developed. Orbital sulcus deep. Ratio of width of frontal ridge (excluding margin) to width of antennal socket (excluding margin): 1.10–1.20. Vertex with irregular sparse and extremely minute punctures. Number of punctures on orbit: none. Number of punctures on frons (triangular area surrounded by frontolateral sulcus and clypeus): 2–3. Number of setae on clypeus: approximately 15. Number of setae on labrum: 6. Anterior margin of labrum more or less straight.

Pronotum without longitudinal impressions near basal margin. Deep row of large punctures at base of pronotum absent. Pronotal base evenly convex. Lateral margins of pronotum slightly convex, converging forward. Anterolateral prothoracic callosity moderately developed, somewhat rounded. Posterolateral prothoracic callosity poorly developed. Pronotal punctures as minute as those on head. Diameter of pronotal punctures 3 to 5 times smaller than distance between them.

Elytra with slightly convex sides. Elytral punctures much larger than those on pronotum. Elytral punctures arranged in single rows, including peri-scutellar row. Interspaces between striae of punctures smooth and glabrous. Humeral callus well developed.

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

Aedeagus extremely robust in both lateral and ventral views, round in cross–section. Apex of aedeagus in ventral view narrowing abruptly. Lateral sides of aedeagus in ventral view almost parallel to each other. Ventral longitudinal groove absent. Apical denticle in ventral view minute and acute. Minute transverse wrinkles on ventral side absent. Aedeagus in lateral view evenly curved, somewhat straight near apex. Maximum curvature in lateral view situated at middle.

Types: Chaetocnema himalayana : ♂ (Holotype) ( NHMB), labels: 1) Makal Dara, 31.V.1987; 2) Indien, Dar- jeeling D. Bhakta B.; 3) Holotypus, Chaetocnema himalayana m. L. Medvedev, det. 1992 . 1♂ (Paratype) ( NHMB), labels: 1) Makal Dara, 31.V.1987; 2) Indien, Darjeeling D. Bhakta B.; 3) PARATYPUS .

Material: 1 ( IZCAS), labels: 1) Tibet, Motuo, Bangxin, 1200–1400 m, 1982.xi.28, coll. Yinheng Han; 2) Chaetocnema melonae Chen ; 3) Chaetocnema melonae Chen, 1934 , Det. Yongying Ruan, 2016.

Remarks: The type of Chaetocnema melonae Chen, 1934 is probably lost. Chen (1934) stated that the type is in “Paris Museum” (i.e., MNHN), but we can not locate the material in the same museum.

Chen (1934) provided a thorough description for C. melonae , we compared it with the holotype of C. himalayana . C. himalayana is synonymized with C. melonae as they are identical in all characters we can compare, for instance: both of the two species with large body size (approximately 3 mm), body color metallic blue, femora deep piceous with metallic luster, tibiae and tarsi red brown, head minutely and sparsely punctate, pronotum also with minute punctures, antennae long and reaching middle of elytra.

Chaetocnema melonae closely resembles C. duvivieri . However, it can be differentiated from C. duvivieri by the larger body size, broader and more convex body shape and the differences in the shape of aedeagus.

Figures

FIGURE 46. Chaetocnema melonae. A Holotype of C. himalayana, habitus. B Holotype of C. himalayana, pronotum and periscutellar area. C Holotype of C. himalayana, head, frontal view. D Aedeagus, ventral view. E Aedeagus, lateral view. F Apex of aedeagus, ventral view. G Holotype of C. himalayana, hind tibia. H Last abdominal ventrite of male.