Plateumaris shirahatai Kimoto, 1971

Geiser, Elisabeth, 2023, Revision of the Palaearctic species of the genus Plateumaris C. G. Thomson, 1859 (Coleoptera, Chrysomelidae, Donaciinae), ZooKeys 1177, pp. 167-233 : 167

Plateumaris shirahatai Kimoto, 1971

Fig. 13

Plateumaris shirahatai Kimoto, 1971: 1.

Plateumaris macropenis Nakane, 1999: 45.

Plateumaris obsoleta ? Plateumaris obsoleta Jacobson, 1894.

Type localities.

Plateumaris shirahatai : Japan, Honshu, Yamagata Prefecture, Shizu, Gassan; Plateumaris macropenis : Japan, Honshu, Oze.

Type material.

Holotype of P. shirahatai : Japan • 1♂, Yamagata Prefecture, Shizu, Gassan; 17 Jun 1960; K. Shirahata leg.; Entomological Laboratory, Faculty of Agriculture, Kyushu University, Fukuoka. The holotype was not examined.

Paratype. Japan • 3 ♀; same data as for the holotype; Japanese Insect Collection No. 21963, OMNH.

Holotype of P. macropenis . Japan • 1 ♀; Honshū, Oze; 15 Jul. 1950; H. Hasegawa leg.; Plateumaris macropenis T. Nakane det.; Laboratory of Systematic Entomology, Faculty of Agriculture, Hokkaido University, Sapporo, Japan.

Taxonomic history and synonymies.

Plateumaris macropenis Nakane, 1999 was synonymized by Hayashi and Shiyake (2004) on page 117. The holotype of P. macropenis is a female specimen of P. shirahatai .

? Plateumaris obsoleta Jacobson, 1894: see below.

Diagnosis.

Pronotal disc rugose, antennae, and legs entirely metallic, although in some specimens the basis of the antennomeres is reddish, A3 = 1.5-2 × A2, tooth on metafemur sharp blade-like or obtuse, pygidium of females rounded, in some specimens slightly emarginate, pygidium of males emarginate or truncate, median process of endophallus notched.

Description.

Size: Males 6.5-7.3 mm, females 7.8-8.2 mm.

Colour: Upper side colour very variable: blackish, blue, green, bronze, cupreous, purple, same colours as P. sericea . Antennae and legs same colour as upper side, in some specimens with reddish parts near the joints.

Head: Rugulosely punctate and pubescent, frontal calli convex, interocular area with a longitudinal median furrow.

Antennae: Entirely metallic with same colour as dorsum, antennomeres in some specimens basically reddish, filiform, A1 robust, club-shaped, A1 = 2 × A2, A3 ≅ 2 × A2, A3 <A4 ≤ A5.

Pronotum: Slightly longer than broad, gradually narrowed posteriorly, dorsal surface with a pair of distinctly raised antero-lateral tubercles, and with a triangular depression medio-basally, disc punctate with transverse rugae, median line indistinct, shallowly furrowed.

Elytra: Interstices of the rows of punctures with close oblique or transverse corrugations and showing a rugged appearance.

Legs: Entirely metallic, same colour as dorsum, in some specimens small reddish parts at the base of the joints, tooth of metafemur prominent and blade-like but also in some specimens obtuse.

Pygidium: Apex pubescent, apical shape in females rounded, in some specimens slightly emarginate, in males emarginate or truncate.

Male genitalia: Median lobe of aedeagus (Fig. 13C ) very similar to P. sericea (Fig. 11D ). Cap of tegmen rounded or slightly notched (Fig. 13B ). Apex of median ejaculatory guide of the endophallus notched (Figs 12B , 13F ).

Remarks.

The only reliable feature to distinguish P. shirahatai from P. sericea is the notched apex at the median ejaculatory guide of the endophallus. The habitus of P. shirahatai looks also very similar to P. roscida , but the latter always has large red parts on the legs and antennae, and their aedeagi are remarkably different (Figs 9 , 13B, C ).

Biology.

The larvae feed on Carex sp. (Narita, 2003). Adults were collected on the florescence of Carex sp. ( Hayashi and Tominaga 2005).

Distribution.

East Palaearctic species. The distribution area of P. shirahatai is situated completely within the eastern area of P. sericea . Unfortunately, it is almost impossible to distinguish P. shirahatai from P. sericea without male genitalia. Both species share the same colour spectrum and same variation of the other external characters.

Records exist for Asia: China (Jilin) [new in PalCat], Japan (Hokkaido and Honshu), Mongolia [new in PalCat], Russia (Far East: Primorsky Krai, Sakhalin), South Korea, South Kuril (Etorofu).

New country records additional to Silfverberg (2010).

China (Jilin): Hayashi (2020); Jilin Province, det. M. Hayashi (Zoological Institute, Chinese Academy of Science, Beijing).

Mongolia: • 2 ♂♂, 1 ♀; central Mongolia, Terelj; 47°59'24"N, 107°27'E; 28 Jun 2004; M. Hayashi leg.; M. Hayashi det.; Hoshizaki Institute for Wildlife Protection, Izumo, Japan. Remark: Some parts of this data are published in Hayashi (2020). The details were obtained from M. Hayashi (pers. comm. 27 May 2020).

This recent record from central Mongolia shows clearly that the distribution area is not known until now. As P. shirahatai was described only in 1971 it is likely that some specimens from the East Palaearctic stored in collections may be identified as P. sericea .

Material examined.

20 specimens from Hokkaido and Honshu.

Figures

Figure 9. Plateumaris roscida aedeagus, photographed from different angles and drawings in frontal view A, B specimen from Primorsky Krai (ZMS) C specimen from Amur Oblast (NHMB) D median lobe E cap of tegmen (A-C photographs by E. Geiser, D, E drawings by G. Geiser). Scale bars: 1 mm.

Figure 11. Plateumaris sericea A-C habitus illustrating variability in colours, but there are more D, E aedeagus: two examples of the variability of the shape of the median lobe (photographs by K. Matsumoto). Scale bars: one unit - 1 mm.

Figure 12. Schematic sketch of the endophallus. Median ejaculatory guide blackened A Plateumaris sericea (and specimens identified as P. discolor) with apex of median ejaculatory guide rounded. The endophalli of specimens from Poland, Italy and Japan all look the same as in this sketch B Plateumaris shirahatai with apex of median ejaculatory guide notched (drawings by G. Geiser based on photographs from Askevold 1991 and Hayashi 2020).

Figure 13. Plateumaris shirahatai A habitus (photograph by K. Matsumoto) B cap of tegmen, shape slightly variable C median lobe (B, C from Hayashi 2020) D, E habitus from dorsal and ventral F endophallus (D-F photographs by M Hayashi). Scale bars: one unit - 1 mm (A); 0.5 mm (B-E).