Chaetocnema (Chaetocnema) wallacei Baly, 1877

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 : 115-117

45. Chaetocnema (Chaetocnema) wallacei Baly, 1877

( Fig. 67 )

Chaetocnema wallacei Baly, 1877: 171 . TL: Malakka. TD: BMNH. Lectotype designated here.

Chaetocnema subcostata Jacoby, 1889: 203 . TL: Myanmar. TD: MCZC. (Syn. Nov.)

Chaetocnema vietnamica Medvedev, 2009: 50 [nec. Chaetocnema vietnamica Chen & Wang, 1980: 4 ]. (Syn. Nov.)

Distribution: China (Taiwan), Myanmar, Peninsular Maylaysia ( Mohamedsaid, 2004), Singapore, Philippines.

Host plants: Pepper ( Piperaceae : Piper nigrum L.) (label data on a single specimens in BMNH).

Description: Body length: 3.50–4.50 mm. Body width: 1.70–1.90 mm. Ratio of length of antenna to length of body: 0.60–0.65. Ratio of elytron length (along suture) to width (maximum): 2.55–2.65. Ratio of pronotum width (at base) to length: 1.70–1.75. Ratio of length of elytron to length of pronotum (along middle): 2.60–2.70. Ratio of width of elytra at base (in middle of humeral calli) to width of pronotum at base: 1.02–1.05.

Body unicolorous, red brown to deep brown, with slight bronzy luster on pronotum and head. Pronotum and head finely reticulated. Antennae completely yellow brown, with distal ones slightly darkened. Pro- and mesofemora red brown, color slightly deeper than tibiae. Metafemora deep reddish brown, color deeper than pro- and mesofemora.

Head hypognathous. Frontal ridge narrow and convex. Frontolateral sulcus present. Suprafrontal sulcus weak. Orbital sulcus deep. Ratio of width of frontal ridge (excluding margin) to width of antennal socket (excluding margin): 1.75–1.80. Four to six weak punctures on vertex on each side near eye. Numerous of rugged punctures scattered on orbit. Number of setae on clypeus: approximately 25. Number of setae on labrum: 6. Anterior margin of labrum flat or slightly convex in middle.

Pronotum without longitudinal impressions near basal margin. 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 1.5 to 2 times smaller than distance between them.

Elytra gently convex at lateral sides. Elytral punctures distinctly larger than those on pronotum. Elytral punctures arranged in single rows, including peri-scutellar row. Interspaces between striae of punctures smooth and costate. 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.

Apex of aedeagus in ventral view narrowing gradually with obscure polygonal impressions laterally. Ventral longitudinal groove absent. Apical denticle in ventral view poorly developed. Minute transverse wrinkles on ventral side absent. Aedeagus in lateral view unevenly curved, more or less straight near apex, maximum curvature in lateral view situated at base.

Spermathecal receptacle pear-shaped. Spermathecal duct coiled. Spermathecal pump much shorter than receptacle, with cylindrical apex. Vaginal palpus (before apex) narrowing from base till middle, thence approximately parallel-sided. Anterior sclerotization of vaginal palpus slightly widening anteriorly. Posterior sclerotization longer than wide. Anterior sclerotization wider than posterior.

Types: Lectotype of Chaetocnema wallacei Baly : 1 male (BMNH), 1) Type H.T.; 2) MT. Ophir, 4000; 3) Baly Coll.; 4) Chaetocnema wallacei Baly , Malacca; 5) Lectotype Chaetocnema wallacei Baly, 1877 Des. Ruan et al., 2016 .

Material: : 1♀ ( USNM, probable type material used for original description by Baly), Singapore, G. Lewis, 1915–38, Chaetocnema wallacei Baly (in regular white label), Chaetocnema wallacei Baly (in red label). 1 ( BMNH), Baly coll. 1 ( BMNH), Ex. F. M. S. Museum, B. M. 1955–354, Singapore S. S., Dec: 1922, H. C. Alsaham; 2 ( BMNH), Singapore, G. Lewis, 1915–28; 1 ( BMNH), Singapore, 96–10; 2 ( BMNH), Singapore, 22.XI–19, XII.1915, Dr. M. Cameron; 11 ( BMNH), Singapore, C. J. Saunders, B. M. 1933–227. 1 ( BMNH), PAHANG F.M.S., Kuala, jungle c 350’, Nov.25, 1921, H. M. Pendlebury, Ex F.M.S. Museum, B. M. 1955–354, Chaetocnema wallacei Baly, Det. G. E. Bryant ; 1 ( BMNH), Malay Penin: Selangor, F.M.S., Kuala Lumpur, July 26,192 2, H. M. Pendlebury; 1 ( BMNH), Perak F.M.S., Larut Hills, 3700–4000ft, 11 Feb: 1932, H. M. Pendlebury, Ex F.M.S. Museum, B. M. 1955–354; 1 ( BMNH), Malay Penin, Kuala Lumpur, Aug: 22 nd, 1920, Ex F.M.S. Museum, B. M. 1955–354; 1 ( BMNH), Malaya, Kuala Lumpur, Oct. 2 nd, 1934, Ex F.M.S. Museum, B. M. 1955–354; 1 ( BMNH), Selangor, F.M.S., Kuala Lumpur, April 1 st, 1923, H. M. Pendlebury, Ex F.M.S. Museum, B. M. 1955–354; 1 ( BMNH), Malay Penin, PAHANG, F.M.S., Kuala, 300’, Nov. 27, 1921, Ex F.M.S. Museum, B. M. 1955–354; 1 ( BMNH), Malaya, Kuala Lumpur, Nr: L. Gardens, Coll. H. M. Pendlebury, 25–8–1935, Ex F.M.S. Museum, B. M. 1955–354; 1 ( BMNH), Perak F.M.S., Larut Hills, 4500ft, 21 Feb: 1932, H. M. Pendlebury, Ex F.M.S. Museum, B. M. 1955–354; 1 ( BMNH), Selangor, F.M.S., Kuala Lumpur, Aug. 12, 1922, H. M. Pendlebury, Chaetocnema wallacei Baly, Det. G. E. Bryant ; 1 ( BMNH), SIAM, KWAI NOI,WAN PO, JUNE 1943, EJH. BERWICK, Chaetocnema wallacei Baly, Det. G. E. Bryant, Brit. Mus., 1954 –365; 3 ( BMNH), Mt. Matang, W. Sarawak, G. E. Bryant, XII.1913, G. Bryant Coll., 1919–147; 2 ( BMNH), Sarawak: C. J. Brooks, B. M. 1928–193; 1 ( BMNH), Quop, W. Sarawak, III–IV.1914, G. E. Bryant, G. Bryant Coll., 1919–147; 1 ( BMNH), Sarawak: Taiton Bav, pepper, 8–4–63, Coll. R. Lav., Chaetocnema wallacei Baly, Det. Yongying Ruan, 2016 ; 3♂ 4♀ ( USNM), Singapore, Col. Baker, 1927, Chaetocnema sumatrana , det. Medvedev; 4♂ 5♀ ( USNM), Singapore, Col. Baker, 1927, Baker Colln 1927; 1♂ 2♀ ( USNM), Philippines, Mt. Makiling, Luzon, leg. Baker, 1927, Chaetocnema sumatrana , det. Medvedev; 1♀ ( USNM), Ma- laya Selangor, 16miNof Kuala Lumpur, Mar 1949, RTraub, BInsoll, NLHKrauss, Col’n, Chaetocnema sp. det. A. Konstantinov, Chaetocnema sumatrana det. Yongying Ruan, 2016.

Remarks: Based on the study of the original description and photos of Syntype of Chaetocnema subcostata (provided by MCZC), we treat C. subcostata and C. wallacei as conspecific.

Medvedev (2009) did not illustrate Chaetocnema vietnamica Medvedev. However , from the original description, it is clear that C. vietnamica Medvedev is conspecific with C. wallacei . More over, C. vietnamica Medvedev is a junior homonym of C. vietnamica Chen & Wang, 1980 .

Chaetocnema wallacei closely resembles C. montivaga and C. sumatrana . Chaetconema wallacei can be easily differentiated 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 (about 2.9-3.2 mm long). In C. sumatrana and C. montivaga , there are two oblique ridges on the ventro-lateral side of aedeagus. However, the oblique ridges in C. montivaga are much weaker than in C. sumatrana .

Figures

FIGURE 67. Chaetocnema wallacei. A Lectotype, habitus. B Head (Lectotype), frontal view. C Lectotype, pronotum. D Aedeagus, ventral view. E Aedeagus, lateral view. F Vaginal palpi. G Spermatheca. H Pygidium (tergite 7) of female.