Chaetocnema (Chaetocnema) granulicollis Jacoby, 1896

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 : 59-61

16. Chaetocnema (Chaetocnema) granulicollis Jacoby, 1896

( Fig. 36 )

Chaetocnema granulicollis Jacoby, 1896: 439 . TL: Sumatra. TD: BMNH. Lectotype designated here.

Chaetocnema flavipennis Medvedev, 1996: 68 . TL: Philippines (Luzon, Mount Makiling). TD: Medvedev Collection. (Syn. Nov.)

Distribution: Malaysia, Singapore, Philippines ( Medvedev, 1996), Indonesia (Sumatra), India.

Host plants: Unknown.

Description: Body length: 1.70–1.90 mm. Body width: 1.00– 1.10 mm. Ratio of elytron length (along suture) to width (maximum): 2.15–2.25. Ratio of pronotum width (at base) to length: 1.80–1.90. Ratio of length of elytron to length of pronotum (along middle): 2.40–2.50. Ratio of width of elytra at base (in middle of humeral calli) to width of pronotum at base: 1.05–1.10.

Color variable, typical individuals have yellow elytra with brown area near scutellum, or elytra entirely brown in some cases. Head and pronotum bronzy to brown. Antennomeres 1–5 yellow brown, 6–11 brown. Tibiae yellow brown. Pro- and mesofemora light brown. Metafemora dark brown. Pronotum and head rugose.

Head hypognathous. Frontal ridge wide, slightly convex. Frontolateral sulcus present. Suprafrontal sulcus shallow laterally, deep in middle. Orbital sulcus deep and straight. Ratio of width of frontal ridge (excluding margin) to width of antennal socket (excluding margin): 2.95–3.00. Number of punctures on vertex: 60–90, punctures sometimes extremely weak. 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: 13. Number of setae on labrum: 6. Anterior margin of labrum slightly convex at middle.

Base of pronotum without short longitudinal impressions near basal margin, with deep row of large punctures at sides, weak in some specimens. Pronotal base slightly convex, with middle prominently expanded. Lateral margins of pronotum nearly straight, converging forward with maximum width near base. Anterolateral prothoracic callosity strongly developed, forming obtuse angle laterally. Posterolateral prothoracic callosity poorly developed. Diameter of pronotal punctures 2 to 3 times smaller than distance between them.

Elytra with slightly convex lateral sides. All rows of elytral punctures regular and single. Interspaces between rows of punctures smooth and glabrous except the few near scutellum are rugged. Humeral callus well developed.

First male protarsomere slightly larger than second. Excavation of hind tibia moderately deep. Large lateral denticle on metatibia sharp. Metatibial serration proximal to large lateral denticle absent.

Apex of aedeagus unique, arrow-head shaped in ventral view. Ventral longitudinal groove absent. Apical denticle in ventral view absent. Minute transverse wrinkles on ventral side absent. Aedeagus in lateral view unevenly curved, apex sinusoidal. Maximum curvature in lateral view situated near apex.

Spermathecal receptacle pear-shaped. Basal part of spermathecal duct coiled. Spermathecal pump much shorter than receptacle, with cylindrical apex. Receptacle basally wider than apically. Apex of vaginal palpus rounded, with slightly convex lateral margin. Anterior end of anterior sclerotization evenly rounded. Posterior sclerotization longer than wide. Both width and length of posterior sclerotization greater than that of anterior sclerotization.

Types: Lectotype: 1♂ ( BMNH), labels: 1) Type H.T.; 2) Sumatra Siboga X.90 – III.91 E. Modigliani; 3) Jacoby Coll. 1909–28 a; 4) Chaetocnema granulicollis Jac. ; 5 ) Lectotype Chaetocnema granulicollis Jacoby, 1896 Des. Ruan et al., 2016 .

Paralectotype: 3♀ ( BMNH), labels: 1) Sumatra Balighe X.90 – III.91 E. Modigliani; 2) Jacoby Coll. 1909–28 a.; 3) Lectotype Chaetocnema granulicollis Jacoby, 1896 Des. Ruan et al., 2016 .

Material: 1♀ ( USNM), Malaysia, Sabah, 7km NNW Kudat, Tanjung Tajau , 19.IX.1983, loan from USNMNH 2065634 ; 1♂ ( BMNH), Sarawak ( Malaysia), on vegetable, 8–vii–63, coll. S. KUEH, Chaetocnema granulicollis Jacoby, 1896 , Det. Yongying Ruan , 2016; 1♂ ( BMNH), Singapore, C. J. Saunders , B.M. 1933–227, Chaetocnema granulicollis Jacoby, 1896 , Det. Yongying Ruan , 2016; 3♂ 1♀ ( USNM), India, Assam Chabua , 20.II.1944, D. E. Hardy, loan from USNMNH 2065634 ; 1♂, Chabua , Assam, India, 2–X–43, DEHardy, Chaetocnema flavipennis Medvedev, 1996 det. Yongying Ruan , 2016.

Remarks: Specimens of C. granulicollis , even from the same locality, vary greatly. For instance, the general color of elytra vary from yellow to dark brown; punctation of head and pronotum range from weak to strong and even the shape of the apex of aedeagus may vary slightly.

Figures

FIGURE 36. Chaetocnema granulicollis. A Male habitus. B Pronotum and peri-scutellar area. C Head, frontal view. D Aedeagus, ventral view. E Aedeagus, lateral view. F Apex of aedeagus, ventral view. G Vaginal palpi. H Spermatheca. I Pygidium (tergite 7) of female.