Chaetocnema (Chaetocnema) hainanensis Chen, 1933

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 : 61-65

18. Chaetocnema (Chaetocnema) hainanensis Chen, 1933

( Figs. 38 , 39 )

Chaetocnema hainanensis Chen, 1933: 228 . TL: China, Hainan. TD: MNHN??.

Chaetocnema kwangsiensis Chen, 1939: 32 . TL: China, Yaoshan. TD: IZCAS. Lectotype designated here. (Syn. Nov.) Chaetocnema assamensis Scherer, 1969: 161 . TL: Assam, India. TD: NHMB. (Syn. Nov.)

Distribution: China (Jiangxi, Fujian, Guangdong, Hainan, Hongkong, Guangxi), Vietnam, India, Sri Lanka, Indonesia, Singapore.

Host plants: Unknown.

Description: Body length 1.80–1.95 mm, body width 0.95–1.00 mm. Ratio of elytron length (along suture) to width (maximum): 2.30–2.40. Ratio of pronotum width (at base) to length: 1.55–1.65. Ratio of length of elytron to length of pronotum (along middle): 2.35–2.50. 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: 1.20–1.30.

Elytra, pronotum and head coppery. Antennomeres 1–5 completely yellow, 6–11 brownish yellow. Tibiae and tarsi completely yellow. Color of pro- and mesofemora light brown. Color of metafemora dark brown.

Head hypognathous. Frontal ridge wide and slightly convex. Frontolateral sulcus present. Suprafrontal sulcus shallow, but distinct, arched. Ratio of width of frontal ridge to width of antennal socket: 2.00–2.10. Frons with long setae laterally. Vertex flat, situated on same level as orbit, with 5–8 punctures near eye.

Base of pronotum without longitudinal impressions. Pronotum without deep row of large punctures at base. Pronotal base evenly convex. Area adjacent to mid basal margin of pronotum covered with punctures. Pronotum without shallow antebasl transverse impression. Lateral margins of pronotum nearly straight, slightly converging anteriorly. Anterolateral prothoracic callosity truncate, facing anterolaterally. Posterolateral prothoracic callosity slightly projects beyond lateral margin of pronotum. Diameter of pronotal punctures 2 to 3 times smaller than distance between them.

Elytra with sides parallel to each other. Scutellar row of elytral punctures regular and single. Second to eleventh rows of punctures regular. Humeral callus moderately developed.

First and second male protarsomeres, length to length ratio: 1.30–1.40. Large lateral denticle on metatibia moderately sharp. Metatibial serration proximal to large lateral denticle absent.

Apical third of aedeagus slightly widening. Apex of aedeagus in ventral view narrowing abruptly. Ventral longitudinal ridge in middle of aedeagus absent. Apical denticle of aedeagus in ventral view well differentiated, narrowly rounded apically. Apical denticle of aedeagus in lateral view strongly curved dorsally. Minute transverse wrinkles on ventral side of aedeagus absent. Aedeagus in lateral view abruptly curved at base and apex, straight at middle. Maximum curvature of aedeagus in lateral view near apex.

Spermathecal pump much shorter than receptacle, apex flattened. Spermathecal receptacle oblong-flask shaped. Maximum width of receptacle situated basally. Receptacle basally wider than apically. Apex of vaginal palpus subtriangular, with convex lateral margin. Vaginal palpus narrowing from base till middle, thence slightly widening towards apex. Anterior sclerotization of vaginal palpus strongly widened anteriorly. Anterior end of anterior sclerotization broadly rounded. Posterior sclerotization longer than wide. Posterior sclerotization wider than anterior.

Types: We could not locate the Holotype neither in MNHN nor IZCAS. However, we could examine a Topotype determined by Prof. Chen in BMNH.

Topotype of Chaetocnema hainanensis (with the same accurate locality as the type, and the label is in the author’s handwriting): 1♂ (BMNH) 1) Hainan Is. LohMaChuen, S.W. of Noda Aug.10; 2) Lingnan University 5 th. Hainan Is. Exped. 1929; 3) Press by Inp. Inst. Ent. Brit. Mus. 1933–295; 4) Chaetocnema hainanensis Chen.

Holotype of Chaetocnema assamensis Scherer, 1969: 1 ♂ ( NHMB): 1) Assam, Khasi–Hills, Cheerapunji , 1300 m, V.1961, leg. G. Scherer; 2) ♂; 3 ) Holotypus, Chaetocnema assamensis sp. nov. det. Dr. G. Scherer, 1965.

Paratype of Chaetocnema assamensis Scherer, 1969: 2 ♀ ( NHMB): 1) Assam, Khasi–Hills, Cheerapunjica , 1300 m, V.1961, leg. G. Scherer; 2) ♀ ; 3) Paratypus, Chaetocnema assamensis sp. nov. det. Dr. G. Scherer, 1965.

Lectotype of Chaetocnema kwangsiensis Chen, 1939: 1 (IZCAS), labels: 1) Yaosan, V–VI, 1938; 2) Chaetocnema kwangsiensis Chen ; 3) Chaetocnema hainanensis Chen ; 4) Lectotype Chaetocnema kwangsiensis Chen Des. Ruan et al.

Material: 1♂ 1♀ ( IZCAS), China, Hongkong, Chaetocnema hainanensis Chen ; 1♂ ( IZCAS), China, Shaluodong , Hongkong, V. 2013, leg. Yongying Ruan ; 1♂ ( IZCAS), China, Hong Kong , Shaluodong, V. 2013, Yongying Ruan, Chaetocnema hainanensis Chen, 1933 , det. Ruan ; 1♀ ( IZCAS), Vietnam, Mont Bavi , Tonkin, VIII.1940, leg. P. A. Cooman ; 4 ( BMNH), SULAWESI TENGAH ( Indonesia): Nr. Morowali , Ranu River Area, 27.i.–20.iv.1980, M.J.D. Brendell, B.M. 1980–280, Chaetocnema spp. det. K. Nadein 2007, Chaetocnema hainanensis Chen, 1933 , Det. Yongying Ruan, 2016; 1♂ 1♀ ( BMNH), Singapore, C. J. Saunders , B.M. 1933–227, (near) Chaetocnema hainanensis Chen, 1933 , Det. Yongying Ruan , 2016; 1♂, Sri Lanka, Pol. Dist. 10 mile east of Habarana, blacklight, 650 foot, 12.XII.1976, leg. G. F. Hevel et al. ( USNM) .

Remarks: Chaetocnema hainanensis closely resembles C. luisiadae Medvedev from the Australian Region as the base of elytra is narrower than the base of pronotum in both of them. However, C. luisiadae has larger punctures on dorsum and head. Chaetocnema hainanensis has apex of aedeagus abruply narrowed with broader denticle, while C. luisiadae has apex of aedeagus gradually narrowed without denticle.

Chaetocnema hainanensis has a distinct oblique ridge on either side ventrally on the aedeagus. Aedeagus of this species resembles that of C. philippina which also has ridges on either side ventrally. However, these two species are distinctly different in the general shape of aedeagus and other external characters.

Some specimens from Singapore and Hongkong have comparatively sharper and more prominent apical denticle of aedeagus. However, all other characters are identical with other specimens. We treat them conspecific till more eveidences are gathered in support of differentiating them from C. hainanensis .

Chaetocnema kwangsiensis was originally described by Chen in 1939 based on a single specimen. We could not locate the type in IZCAS. However, we found a single specimen collected in Yaoshan with dating V–VI, 1938 and labeled as ‘ Chaetocnema kwangsiensis Chen’. This has an extra label: ‘ Chaetocnema hainanensis Chen’. The label data on this specimen (Yaoshan, V–VI) is the same as given by Chen in his original description. Another circumstantial evidence is that C. fortecostata was published in the same manuscript without a ‘type label’. Based on these findings, we are convinced that the single specimen with the label ‘Yaoshan, V–VI, 1938’ in IZCAS is the Holotype of Chaetocnema kwangsiensis Chen. Most probably the label ‘ C. hainanensis ’ was added by the author himself or another worker who found that C. hainanensis and C. kwangsiensis are conspecific. Hence we consider this single specimen as the Holotype of Chaetocnema kwangsiensis Chen.

Based on the original description of C. kwangsiensis ( Chen,1939: 32) and C. hainanensis ( Chen, 1933: 228) , all the characters are identical with each other. Hence we synonymize C. kwangsiensis with C. hainanensis .

Figures

FIGURE 38. Chaetocnema hainanensis. 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 Pygidia (tergite 7) of females.

FIGURE 39. Chaetocnema hainanensis. A Lateral view of habitus. B Head, frontal view. C Labrum, indicating special laterofrontal angle. D Ventral view of habitus. E abdominal ventrites.