Chaetocnema (Chaetocnema) montivaga Maulik, 1926

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 : 77-79

26. Chaetocnema (Chaetocnema) montivaga Maulik, 1926

( Fig. 47 )

Chaetocnema montivaga Maulik, 1926: 204 . TL: India. TD: BMNH. Lectotype designated here.

Distribution: Myanmar ( Mohamedsaid, 2004), Malaya Halbina, Peninsular Malaysia ( Mohamedsaid, 2004), India (Assam).

Host plants: Unknown.

Description: Body length: 2.80–3.20 mm. Body width: 1.65–1.75 mm. Ratio of elytron length (along suture) to width (maximum): 2.55–2.60. Ratio of pronotum width (at base) to length: 1.70–1.75. Ratio of length of elytron to length of pronotum (along middle): 2.80–2.90. Ratio of width of elytra at base (in middle of humeral calli) to width of pronotum at base: 1.10–1.11.

Body unicolorous, red brown to deep brown entirely. Pronotum and head finely reticulated. Antennae completely yellow brown, with distal ones slightly darker. Pro- and mesofemora red brown—concolorous with tibiae and tarsi. Color of metafemora deep red brown, deeper than that of pro- and mesofemora.

Head hypognathous. Frontal ridge narrow and convex. Frontolateral sulcus present. Suprafrontal sulcus moderately developed. Supraantennal, orbital sulci deep. Ratio of width of frontal ridge (excluding margin) to width of antennal socket (excluding margin): 1.40–150. Three to five weak punctures on vertex on each side near eye. Orbit glabrous, occasionally with few small rugged punctures. Number of setae on clypeus: 15-20. Number of hairs on labrum: 6. Anterior margin of labrum slightly convex.

Pronotum with two barely visible longitudinal impressions near basal margin on either side. Deep row of large punctures at base of pronotum absent. Pronotal base convex, slightly expanded at middle. Lateral margins of pronotum almost straight, converging forward. Anterolateral prothoracic callosity truncate, oblique and long. Posterolateral prothoracic callosity poorly developed. Diameter of pronotal punctures 2 to 3.5 times smaller than distance between them.

Elytra gently convex at sides. Elytral punctures larger than those on pronotum. Elytral punctures arranged regularly in single rows, including peri-scutellar row. Interspaces between striae of punctures strongly costate. Number of rows of minute punctures on each interspace: 2–3. Humeral calli well developed.

First male protarsomere slightly larger than second, larger than that of female.

Apex of aedeagus in ventral view narrowing gradually. Ventral longitudinal groove absent. Apical denticle in ventral view moderately developed, acute. In ventral view, apex of aedeagus streaked with oblique wrinkles and grooves, which is quite unique amongst Oriental Chaetocnema species. Aedeagus in lateral view unevenly curved, more or less straight near apex, maximum curvature in lateral view situated at base.

Types: Lectotype: 1 male ( BMNH), labels: 1) Type; 2) Doherty; 3) Assam Patkai Mts. ; 4) Fry Coll., 1905.100; 5) Chaetocnema montivaga M., Det. S. Maulik, Type, 1925; 6 ) Lectotype Chaetocnema montivaga Maulik, 1926 Des Ruan et al., 2016 .

Paralectotype: 1 male and 2 female ( BMNH), labels: 1) Doherty; 3) Assam Patkai Mts. ; 4) Fry Coll., 1905.100; 5) Chaetocnema montivaga M., Det. S. Maulik, Type , 1925; 6) Paralectotype Chaetocnema montivaga Maulik, 1926 Des Ruan et al., 2016 .

Remarks: Chaetocnema montivaga resembles C. wallacei and C. sumatrana . Chaetocnema wallacei differs from C. sumatrana and C. montivaga by its larger body size and narrower body shape. Body length of wallacei is about 3.5-4.5 mm, while C. sumatrana and C. montivaga are much smaller, usually about 2.9-3.2 mm. In C. sumatrana and C. montivaga , there are two oblique ridges on ventro-lateral side of aedeagus. However, the oblique ridges in C. montivaga are much weaker than in C. sumatrana .

Figures

FIGURE 47. Chaetocnema montivaga. A Male habitus (Lectotype). B Head, frontal view (Lectotype). C Pronotum and periscutellar area (Lectotype). D–D1 Aedeagus, ventral view (Lectotype and Paralectotype). E Aedeagus, lateral view (Paralectotype). F Apex of aedeagus, ventral view (Lectotype). G Middle part of aedeagus, ventral view (Lectotype), indicating two ridges and numerous streaks. H Hand drawing of middle part of aedeagus, ventral view, indicating two ridges and numerous streaks.