Plateumaris amurensis Weise, 1898

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 amurensis Weise, 1898

Fig. 3

Plateumaris amurensis Weise, 1898: 179.

Type locality.

Amur [assumed Russia, further details unknown].

Type material.

Types could not be located so far. In his original description (translation in Geiser and Geiser 2023), Weise gave no indication from whom he received the material, where the type is stored, nor the number of specimens he studied.

Taxonomic history and synonymies.

Weise (1898) assumed a relationship to P. discolor and further compared it with P. weisei that is similar in colour. Reitter (1920) mentioned both P. amurensis and P. weisei in a footnote with some characters from their original descriptions but not in his identification key. He also noted no distinguishing characters. Both species are also mentioned in the catalogue of Winkler (1930). Goecke (1937) regarded P. amurensis as synonymous with P. weisei in his modification to Reitter’s (1920) identification key, but he provided no reason or reference for this synonymy and subsequently, P. amurensis was considered a synonym ( Goecke 1960; Jolivet 1970). Askevold (1991) agreed with Goecke’s view. Only in the key of Gressitt and Kimoto (1961) is P. amurensis regarded as a species propria with different characters to P. mongolica (which is now a synonym of P. weisei ) but those characters are not adequate to distinguish these two species. Medvedev (1992) regarded P. amurensis a valid species; Hayashi (2001) then confirmed that P. amurensis was a species propria. Many external characters are highly variable and sometimes overlap with the characters of P. weisei . Due to the situation described above, specimens of P. amurensis are sometimes hidden in collections because they were identified as P. weisei .

Diagnosis.

Metafemur with a prominent, blade-like tooth, apical part of median lobe of aedeagus gradually narrowed towards the apex.

Description.

Size: 7.1-7.7 mm.

Colour: Pronotum and elytra bronze, cupreous, also which greenish reflex.

Head: Supraocular furrow indistinct, vertex pubescent with deep median line. Antennae entirely rufous, sometimes apex darkly rufous; A4 = 1.6 × A2, A5 longest and ~ 2.5 × as long as wide.

Pronotum: More or less quadrate, anterior part slightly widened by shallow anterior tubercles, disc shiny, coarsely punctate, rugose, sometimes with microsculpture in major part of the disc, basal sulcus prominent with rugae and dense punctures, median groove indistinct.

Elytra: Sparsely rugose, shiny, densely punctate on disc.

Legs: In most specimens rufous, sometimes apical area of femora dark, metafemur with a prominent, blade-like tooth (Fig. 3B ; Table 3).

Pygidium: Apex pubescent, shallowly emarginate or sometimes truncate in male and rounded in female. Last sternite entirely coppery but apex at middle part rufous, apical shape variable in male, acute in female (Table 3).

Ovipositor: Elongate, both sides paralleled, apical angle acute, subapical corner with teeth, apex remarkably prominent (Table 3).

Aedeagus: With median lobe, acute but slightly rounded at the apex; cap of tegmen gradually narrowed distally, notched, or sometimes rounded at apex (Fig. 3C-E ).

Similar species.

The most similar species is Plateumaris weisei and the main distinguishing characters are shown in Table 3. Otherwise, the East Palaearctic Plateumaris species are not easy to distinguish. I found specimens of P. amurensis in museums also identified as P. roscida , P. sericea , or as their synonyms.

Biology.

Host plant and larvae are unknown.

Distribution.

East Palaearctic only. Records exist for Asia: Russia: Transbaikalia, Republic of Sakha (Yakutia): southern part of river Lena; Amur Oblast, Khabarovsk Krai, Primorsky Krai, Sakhalin, Kurile Islands. Sometimes P. amurensis is mentioned from Japan (e.g., Bieńkowski 2014) but these are erroneous records caused by confusion with P. weisei ( Hayashi 2001, 2020).

Material examined.

15 specimens from different localities in East Siberia and Far East .

Figures

Figure 3. Plateumaris amurensis A habitus B metafemur with prominent tooth C aedeagus (A-C photographs by E. Geiser) D median lobe E cap of tegmen (D, E from Hayashi 2001). Scale bars: 1 mm (A-C); 0.5 mm (D, E).