Chrysolina (Hypericia) nikkoensis ( Jacoby, 1885 )

Mikhailov, Yu. E., 2024, REVIEW OF LEAF BEETLES OF THE SUBGENUS HYPERICIA BEDEL, 1899 (COLEOPTERA: CHRYSOMELIDAE: CHRYSOLINA) FROM EAST ASIA, Far Eastern Entomologist 499, pp. 1-18 : 10-13

Chrysolina (Hypericia) nikkoensis ( Jacoby, 1885)

Figs 11, 12 , 13–16

Chrysomela nikkoensis Jacoby, 1885: 207 ("Nikko, Yunoshiku, Urasa", syntypes in

NHMUK, examined). Chrysolina (Hypericia) nikkoensis : Bechyne, 1950: 155. Chrysolina (Hypericia) ohoi Chûjô, 1958: 50 (" Formosa: Taihoku-Si, Taihoku-Syû").

Synonymised by Bienkowski (2019). Not confirmed here.

TYPE MATERIAL. Syntype, male with labels: Type / H. T . [p, round circled with broad red band] | Nikko. / VIII – 18.VII [p] | Japan./ G. Lewis. / 1910–320. [p] | Syntype [p, round circled with broad blue band] | Chrysomela nikkoensis Jac. [h] | NHMUK 014379807 [p] ( NHMUK); syntype, male with labels: Japan [h] | Jacoby coll./ 1909-28a [p] | nikkoensis Jac. [h] | Syntype [p, round circled with broad blue band] | NHMUK 014379806 [p] ( NHMUK).

OTHER MATERIAL EXAMINED. Russia: South Kurile Islands , Shikotan Island , Krabovaya bay, env. of Krabozavodskoye, 43º50'04.75" N, 146 º 45'12.46" E, 4–8.VII 2012, 2 ♀, Yu.N. Sundukov leg. ( MPSU); the same locality, 21–22.VII 2012, 3♂, 2♀, Yu.N. Sundukov leg. ( YMC); the same locality, 8–9.VIII 2012, 1♂, 2♀, Yu.N. Sundukov leg. ( MPSU) .

REDESCRIPTION (based on original description and the specimens from Kurile Islands).

Body: subparallel, moderately convex, males obovate, females subquadrate ( Figs. 13–16 ). Body length: 5.2–6.1 mm (male), 5.7–6.3 mm (female), width: 3.4– 3.8 mm (male), 3.9–4.1 mm (female). Dorsum shining, smooth, violet blue or dark blue; underside and legs black, with feeble bluish reflex. Antennae, maxillary palpi and tarsi dark brown.

Head: frontoclypeus smooth, entirely impunctate; frontal suture absent, epicranial suture slightly deepened. Last maxillary palpomere axe-shaped, apically truncated, 1.2x longer then broad, 1.4x longer and 1.2x narrower than previous palpomere. Relative length of antennomeres 1–3 as ratios 7, 4, 6. Tenth antennomere 1.4x longer than broad, eleventh antennomere – 2.1x. Orbital lines short and narrow, far not reach antennal insertion. Antenna inserted 1.6x closer to eye than to clypeus.

Thorax: pronotum transverse, twice broader than long in males, in females 1.9x broader than long; broadest behind middle, evenly rounded laterally; pronotal disc evenly convex, smooth and shining, looks like impunctate, but covered with sparse very fine punctures; width between anterior angles 1.8x less than basal width. Anterior angles acute and somewhat produced; basal angles obtuse. Both basal and apical setiferous pores present. Anterior side broadly margined, widely incised in bracket-shape; basal edge arcuately convex; lateral sides swollen along entire length, lateral callus broad, separated from disc by deep groove with vertical outer border in basal 2/5 and by broad almost obsolete impression with large punctures in anterior part. Prothoracic hypomera with longitudinal furrow, outer side slightly convex and smooth, basal 1/4 covered with sparse punctures and wrinkles; basal fold short and moderately deep; prosternal process narrow, almost flattened longitudinally; anterolateral portion of prosternum flattened medially; prosternum 1.3x shorter than metasternum; metasternum of the same length as first ventrite. Scutellum broadly ovate, smooth.

Elytra with weak humeral callus, subquadrate, each elytron 2.2–2.4 times longer than wide, elytral length 4.2–4.7 mm (males), 4.7–4.9 mm (females). Large primary punctures form scutellar row of 9-12 punctures in males or 12-15 punctures in females and 9 regular paired rows. Punctures in rows sparsely placed. 5th puncture row consists of 20–26 punctures. Secondary punctures fine and sparse, on wider intervals distinctly larger than on pronotum, on narrow intervals between paired rows very fine similar to that on pronotum. Marginal stria with punctures of similar size as in rows. Sutural stria distinct at apical slope. Epipleura inclined outside, visible along entire length. Hind wings developed.

Tarsi narrow in both sexes, fore tarsi (tarsomeres 1-3) 2.2x as long as broad; ratio of width of fore tarsomeres 1–3 in males as 1.8, 1.6, 2.2, in females as 1.7, 1.5, 2.1. All tarsomeres with entire sole beneath in both sexes.

Abdomen: pygidium with impression in basal 2/3. Ventrite 1 broadly margined on anterior edge, covered with sparse fine punctures, only anterior intercoxal process covered with medium-sized punctures. Last ventrite evenly convex, with slightly incised apex, smooth, covered with sparse fine punctures. Aedeagus ( Figs 11, 12 ) with apical projection broad and rounded.

DIFFERENTIAL DIAGNOSIS. Jacoby (1885) indicated the main distinguishing features of Ch. nikkoensis as “shining and almost impunctate disk of the thorax, on which fine punctures are only visible with a strong lens”. Also he indicated that “the interstices between the double rows of punctures at the elytra are finely but distinctly punctured, the double rows themselves consist of strong and regular lines of punctures not very closely approached in pairs”. These features readily distinguish Ch. nikkoensis from Ch. difficilis that have pronotum with dense, distinct punctures and secondary punctures of elytral intervals dense and relatively large ( Fig. 7 ). Also the apical projection of aedeagus in Ch. difficilis is distinctly narrowed ( Figs 8, 9 ).

REMARKS. Bechyne (1950), who placed Ch. nikkoensis in the subgenus Hypericia , indicated that he knew this species only from Japan and the records from continental Asia ( China and Tonkin) were taken from Chen (1934).

Chen (1936: 151) gave the following description. “Coloration variant du vert bronzé au bleu foncé ou violacé, parfois cuivreux; dessous un peu plus foncé. Tête marquée de points très épars, un peu plus serrés sur le clypéus. Pronotum presque lisse sur le disque, la ponctuation étant microscopique; dépressions latérales profondes et bien délimitées en arrière du milieu, mais disparaissant et remplacées par de gros points en avant. Ponctuation des élytres géminée, les points gros et profonds; intervalles marqués de points fins, serrés. – Long.: environ 6 mm. Kouy- Tchéou: région de Pin-Fa; Kiang-Si; Yunnan: Sze-Tsong, Kouang-Si-Hien; Tonkin: Hoa-Binh; aussi du Japon.”.

Chen (1936) treated the beetles from China and North Vietnam externally similar to Japanese Ch. nikkoensis as a same species because he did not examine the aedeagus shape. And it is essential that later on Bechyné (1950) described the new species Chrysolina (Hypericia) gracilis Bechyné, 1950 of a same size of 6 mm and similar colour ( Fig. 17 ) and also from Guizhou province in South China ("prov. Kouy Tcheou: Kouy Yang Fou"). The records of Ch. nikkoensis from North Vietnam by Bechyné (1950) and Bienkowski (2019) were made following Chen (1936) and in reality should also belong to Ch. gracilis .

Bienkowski (2019) compared the photo of the type of Ch. ohoi and the original description of this taxon with the specimens that he treated as Ch. nikkoensis and came to the conclusion, that Ch. nikkoensis and Ch. ohoi were synonyms. However, the aedeagus of Ch. ohoi was not examined and this conclusion was based only on the density of the punctation in the elytral rows ( Ch. ohoi has more than 19 punctures in the 5th puncture row at elytron like Ch. nikkoensis ). But all known specimens of Ch. nikkoensis are violet blue or blackish blue, while Ch. ohoi is bronze ( Lee, 2016). By now Ch. ohoi is the only species of the subgenus Hypericia recorded from Taiwan ( Yang et al., 2015; Lee, 2016) and the indication of Ch. nikkoensis from there by Bienkowski (2019) is based on the incorrect synonymization of these taxa. Ch. nikkoensis is in fact island species distributed only in Japan and South Kurile Islands.

Figures

Figs 8–12. Aedeagus in dorsal and lateral view. 8 – Chrysolina difficilis Motschulsky (Lazo village, Maritime province, Russia); 9 – Ch. difficilis (Naitoushan Mts., Jilin Province, China); 10 – Ch. changbaishana sp. n., holotype (S of Erdaobaihe, Jilin Province, China); 11, 12 – Chrysolina nikkoensis Jacoby (Krabovaya bay, Shikotan Island, Russia). Scale bar = 1 mm.

Figs 13–16. Habitus in dorsal view of Chrysolina nikkoensis Jacoby. 13, 14 – male and female from Shikotan Island, South Kurile Islands; 15, 16 – syntypes, males from Japan. Scale bar = 2 mm. 11

Figs 6–7. Habitus in dorsal view. 6 – Chrysolina changbaishana sp. n., holotype, male (S of Erdaobaihe, Jilin province, China); 7 – Ch. difficilis Motschulsky, male (Naitoushan Mts., Jilin province, China). Scale bar = 1 mm.

Figs 17–20. Habitus in dorsal view and labels of the types. Chrysolina gracilis Bechyně: 15 – holotype, male; 16 - labels of holotype; Ch. fricata Bechyně: 17 – syntype, male; 18 – labels of syntype. Scale bar = 1 mm.