Chaetocnema (Udorpes) merguiensis Bryant, 1941

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 : 168-170

70. Chaetocnema (Udorpes) merguiensis Bryant, 1941

( Fig. 97 )

Chaetocnema merguiensis Bryant, 1941: 409 . TL: Myanmar. TD: BMNH. Lectotype designated here.

Distribution: Laos, Myanmar.

Host plants: Unknown.

Description: Body length 2.70–3.50 mm, body width 1.05–1.35 mm. Ratio of elytron length (along suture) to width (maximum): 2.40–2.50. Ratio of pronotum width (at base) to length: 1.50–1.60. Ratio of length of elytron to length of pronotum (along middle): 2.60–2.70. Ratio of width of elytra at base to width of pronotum at base (in middle of humeral calli): 1.20–1.25. Ratio of maximum width of elytra to that of pronotum: 1.45–1.50. Dorsum metallic green. Antennomeres 1–4 yellow brown, 5–11 dark brown. Pro- and mesotibia yellow. Metatibia partially brown. Pro- and mesofemora light brown. Metafemora dark brown, with metallic luster.

Head hypognathous. Frontal ridge wide and flat. Frontolateral sulcus absent. Suprafrontal sulcus relatively deep, well recognized. Suprafrontal sulcus obcordate. Ratio of width of frontal ridge to width of antennal socket: 1.45–1.55. Frons evenly covered with short white setae. Vertex flat, situated on same level as orbit. Vertex densely and evenly covered with punctures.

Base of pronotum without short longitudinal impressions. Deep row of large punctures at base of pronotum absent. Pronotal base evenly convex. Area adjacent to mid basal margin of pronotum covered with punctures. Pronotum without shallow antebasal transverse impression. Lateral margins of pronotum slightly convex, converging forward. Anterolateral and posterolateral prothoracic callosities poorly developed.

Elytra with convex lateral sides. Scutellar row of elytral punctures confused, geminate. Second to eleventh rows of punctures regular. Humeral callus well developed.

First and second male protarsomeres, length to length ratio: 1.35–1.40. First and second male protarsomeres, width to width ratio: 1.50–1.60. Large lateral denticle on metatibia obtuse. Metatibial serration proximal to large lateral denticle absent. Metatibia proximal to denticle in dorsal view convex. First male protarsomere, maximum width to width at base ratio: 2.00–2.10.

In ventral view, aedeagus somewhat parallel sided, apex narrowing abruptly. Ventral surface of aedeagus deeply concave, with sharp margins. Ventral longitudinal ridge in middle of aedeagus absent. Longitudinal groove apically wider than basally. Apical denticle of aedeagus in ventral view well differentiated, long, wide, with apex truncate, in lateral view straight. Minute transverse wrinkles present on ventral side of apex. Aedeagus in lateral view evenly and strongly curved. Maximun curvature of aedeagus in lateral view situated medially.

Spermathecal pump much shorter than receptacle. Apex of spermathecal pump flattened. Spermathecal receptacle sinuate. Maximum width of receptacle situated apically. Receptacle basally narrower than apically. Posterior sclerotization of tignum not well formed, as wide as mid-section. Tignum nearly straight in middle. Anterior sclerotization of tignum wider than mid-section. Apex of vaginal palpus evenly rounded. Vaginal palpus parallel sided in middle. Anterior sclerotization of vaginal palpus slightly widening anteriorly. Anterior end of anterior sclerotization broadly rounded.

Types: Lectotype: 1♀ ( BMNH), labels: 1) Type ; 2) 371; 3) Mergui, Burma, R. N. Parker, I. 1927; 4) Chaetocnema merguiensis , Type, Bryant, Det. G. E. Bryant; 5 ) Lectotype Chaetocnema merguiensis Bryant, 1941 Des. Ruan et al., 2016 .

Material: 1♂ 2♀ ( USNM), Myanmar, Tenasserim , MUS. PRAGENSE, Coll. Helfer, Chaetocnema harita det. I. Lopatin , 1961. 1♀ ( USNM), Laos, Ban Phabat , 27.IV–1V.1997, leg. Jendek, Chaetocnema harita det. Döberl , 1998.

Remarks: Chaetocnema merguiensis resembles C. westwoodi , however, the former can be differentiated from the latter by the metallic green dorsum, longer antennae and much larger size.

Figures

FIGURE 97. Chaetocnema merguiensis. A Male habitus. B Pronotum. C Head, frontal view. D Aedeagus, ventral view. E Aedeagus, lateral view. F Apex of aedeagus, ventral view. G Vaginal palpi. H Spermatheca. I Tignum.