Japan, Honshu, Shinkawa-tameike, altitude 770 m, Nishi-yawata-hara, Geihoku-cho, Yamagata-gun, Hiroshima Prefecture.

Holotype : Japan • ♂; Honshu, Hiroshima Prefecture, Yamagata-gun, Geihoku-cho, Nishi-yawata-hara, Shinkawa-tameike; 770 m a.s.l.; 13 Jun 1982; I. Hiura leg.; OMNH-TI-16. The holotype was not examined.

Because this species was not described until 1984 it is possible that some small Plateumaris specimens from Japan are misidentified as another species in old collections.

Habitus (Fig. 2A) like a typical Plateumaris, but with conspicuously short elytra and legs, elytra length is at the most 1.6× longer than wide, colour black or bronze-metallic, also with a bluish or greenish lustre, elytra shiny, antennomeres thicker than in most Plateumaris species, legs reddish but femora dark.

There are comprehensive descriptions in Tominaga and Katsura (1984) and in Hayashi (2020) with many detailed figures so the description below is confined to the essentials.

Size : 6.4–7.6 mm.

Colour : Colour of pronotum and elytra entirely metallic black or reddish coppery, some specimens with a bluish or greenish lustre.

Head : Supraocular furrow indistinct, frontal tubercle weakly convex.

Antennae : Antennae short and robust, slightly shorter than half as long as the body, A1 dark, A2–A11 entirely reddish brown or apical antennomeres with darker parts. A1 is longest, A2 is shortest, A3–A11 are only slightly longer than A2, A3 ≥ A4 ≤ A5.

Pronotum : Slightly longer than wide, outline more or less cordate, gradually narrowed backwards with anterior margin strongly produced forward; dorsal surface with feebly raised anterior and posterior tubercles, disc densely but finely punctate, median line shallow, with a conspicuous broad collar along the posterior margin.

Elytra : Robust and short, 1.6× as long as wide, with arched outer margin, rows of punctures regular, their interstices smooth, usually sparsely but sometimes densely punctate.

Legs : Legs short, reddish brown, partly dark rufous or black, especially the apical half of the femora, metafemur robust in shape, with a tooth; T2 shorter than its width, T1 > T2 < T3.

Pygidium : Entirely rufous, but apical part black, apex pubescent, shallowly emarginate in both sexes.

Aedeagus : See Fig. 2B, C.

Plateumaris akiensis looks similar to P. constricticollis but can be identified by its shorter elytra. In P. constricticollis the elytral length is distinctly > 1.6× longer than wide.

The adults feed on pollen of Carex sp. and Scirpus juncoides (Hayashi 2020). Narita (2003) described the larvae from Carex otaruensis Franch. Scirpus sp. is also thought to be a larval host plant (Hayashi 2020).

Endemic species found in Honshu, Japan. The only records so far are from Hiroshima and Shimane prefectures in south-west Honshu.

Five specimens from Hiroshima prefecture, stored in BMNH, HNHM, and NMPC.

Amur [assumed Russia, further details unknown].

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.

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.

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

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).

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.

Host plant and larvae are unknown.

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).

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

Plateumaris bracatus: Carniola, a historical region which comprised parts of present-day Slovenia.

Type specimens of P. bracatus do not exist anymore. Sadly, Scopoli’s collection of insects from Carniola decayed during his life time. He committed this collection to a printer in Vienna who apparently did not store it adequately. Before all the pictures were printed, Scopoli complained in his 1773 letter to Linnaeus (Brelih et al. 2006) that the insects “had either decayed or fallen apart”.

In nearly all publications the species name has been misspelled “braccata”. The spelling in the original description by Scopoli (1772) is “Prionus Bracatus” with a single “c” (Geiser and Geiser 2023). Scopoli used this epithet presumably because “bracae” means “trousers” or “pants” referring to the clubbed shape of the metafemora. A variant of this word exists in later medieval Latin and was spelled “braccae”, which Schenkling (1917) used in his explanation of the scientific names of beetles. Because the spelling of the original description is linguistically correct it must be preserved unaltered (ICZN, Art. 32.2.1). Because the original description by Scopoli is very short, Weise (1893) published a more detailed redescription (see Geiser and Geiser 2023).

Donacia abdominalis (Olivier, 1800): Silfverberg (2010) cited this synonym as abdominalis (Olivier, 1795). Despite the title page dated 1795, the fourth volume of Olivier’s ’Entomologie, ou histoire naturelle des insectes’ was issued in two parts, one probably in 1795 and the second one in 1800. All new taxa made available in this work have previously been dated 1795 in the literature (Bousquet 2018). In any case, Olivier’s volume does not contain the original description. He also listed another name of this species, Leptura violacea Pallas, and then described the typical characters of P. bracata. Later, P. abdominalis was regarded synonymous with P. rustica because it was mixed up with P. abdominalis Bedel, 1891, who intentionally did not describe it as a new species (see section on P. rustica for details).

Plateumaris fairmairi was first described by LeGrand (1861a) on page 265 as variation of Donacia nigra (see Geiser and Geiser 2023) from a specimen with complete black antennae and legs. The often-mentioned page 89 derives from the reprint (LeGrand 1861b).

Fabricius described Donacia nigra by 1792 (see Geiser and Geiser 2023). He allocated it close to D. festucae which is now synonymous with P. sericea. The name Plateumaris was not established then, but Fabricius (1792) noticed some differences from other Donacia species.

This is the largest Plateumaris species, body length: 8.0–12.0 mm (Fig. 4A).

Head, pronotum and elytra entirely black or with a weak blue, purple or green metallic lustre, antennae and legs reddish brown in most specimens, elytra elongate, ~ 2× as long as wide, side contour of the elytra very straight, almost parallel.

Size : 8.0–12.0 mm.

Colour : Dark, entirely black or at the most with weak blue, purple or green metallic lustre.

Head : Entirely black or with weak metallic lustre. Fine punctures and very fine wrinkles. Antennae minimum as long as the half length of the beetle, basal part of the antennomere always reddish (with rare exceptions), apical part dark; ½ A1 ≥ A2, ½ A3 ≥ A2, A4 ≥ A3, A1 ≈ A4, A5 … A11 ≈ A4.

Pronotum : Cordate, ahead distinctly wider than behind, anterior tubercles only slightly convex, slightly pubescent. Disc with fine punctures, median line well developed, sometimes shortened, but also very shallow and almost invisible in some specimens.

Elytra : Base of elytra with short, distinct setae in most specimens, elytral disc rugose, punctures delicate, not deep, interstices strongly transversely wrinkled; contour of the margin very straight, almost parallel; elytra elongate, ~ 2× as long as wide, ratio of length to width = (1.8–2.1): 1.

Legs : Colour variation from complete reddish brown to dark apical parts and completely dark legs, femora basally very broad, metafemur with broad tooth, robust in male, in female feeble or indistinct.

Aedeagus : see Fig. 4B.

The most similar species is Plateumaris consimilis, which is smaller (6.0–9.2 mm) on average, its elytra are shorter with a ratio of length to width ≤ 1.8, and the outer contour of the elytra are slightly rounded, not parallel.

Plateumaris bracata is monophagous on Phragmites australis (Cav.) Trin. ex Steud., the common reed, Poaceae (Bieńkowski 2014). The beetle can be found concealed in the Phragmites leaf-folds. When feeding, it penetrates the young leaf shoots which later unfold to present a characteristic transverse series of round holes. Donacia clavipes feeds on the same plant species in a similar fashion but, in this case, the series of holes produced are irregularly elongated (Menzies and Cox 1996; Rheinheimer and Hassler 2018). For identification of the larvae see Steinhausen (1994) and Bieńkowski and Orlova-Bieńkowskaja (2004). Despite its large distribution area and its common food plant, its number of specimens stored in museum collections is always remarkably fewer than the number of P. consimilis or P. sericea. Compared with Donacia clavipes, which occurs on the same food plant, the numbers of P. bracata specimens are also much fewer. Recent records are extremely rare.

All parts of Europe except southern Europe and north Scandinavia, continuing to central Asia, including southern parts of Russia and western Siberia. Records exist for Europe: Austria, Belgium, Bosnia-Herzegovina [new in PalCat], Belarus, Bulgaria, Croatia [first record], Czech Republic, Denmark, Estonia, Finland, France, Germany, Great Britain, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Moldavia, Montenegro [first record], The Netherlands, Norway, Poland, Romania, Russia (central and south parts of European Russia), Serbia [new in PalCat], Slovakia, Slovenia, Sweden, Switzerland, Ukraine.

Asia: Azerbaijan, China (Xinjiang [first record]), Georgia, Iran [new in PalCat], Kazakhstan, Kyrgyzstan [new in PalCat], Russia (south Siberia [new in PalCat], west Siberia).

Bosnia-Herzegovina: Mohr (1966b).

Croatia • 3 ex.; Dalmatia; E. Geiser 2019 det.; coll. Frey in NHMB.

Montenegro • 2 ex.; Montenegro; E. Geiser 2019 det.; coll. Frey in NHMB.

Serbia: Gavrilović and Ćurčić (2011) and Mohr (1966b).

China • 2 ex.; Xinjiang, “Ost-Turkestan, Bagratsch-Kul” [Bosten-Lake], Kurla; May 1902; Hauser leg.; E. Geiser 2019 det.; HNHM • 1 ex.; Xinjiang, Kuldscha province, Upper Ili valley [“Ober Jli-Thal”]; 1897; F. Hauser leg.; “Pl. braccata” H. Goecke 1956 det., E. Geiser 2019 vid.; coll. Frey in NHMB. Note: Bosten-Lake lies east of Kurla; Kuldscha is now called Yining (in Chinese). Both Bosten-Lake and Kuldscha are located in north-western Xinjiang, on the northern side of the Ili River in the Dzungarian basin, ~ 70 km east of the border with Kazakhstan.

Iran • 2 ex.; Khorasan-e Razavi province, Sabzevar; 36°12′N, 57°35′E; 1024 m a.s.l.; 23. Aug 2012 (Samin 2018).

Kyrgyzstan: Bieńkowski (2014).

Russia: South Siberia (Gus’kova et al. 2018).

More than 100 specimens from different localities throughout the distribution area.

Plateumaris consimilis: unknown, but possibly in Austria (the country in 1781 was much larger than today) because the original description is in a book titled ‘Enumeratio insectorum Austriae indigenorum’.

Holotype or type series of P. consimilis unknown.

Bechyne (1942) detailed statistics about the different colours and subtle structures on the pronotum of P. consimilis, but without convincing results. He named colour variations as “forma” but conceded that there also existed combinations of colours in between. These names are indicated above for the sake of completeness, but they are irrelevant to systematics.

Schrank de Paula (1781: 155) described Leptura consimilis with bronze and black-golden colouration. On the next page of this publication, he described a new species Leptura assimilis. The difference from the former species is indicated as “black” and the elytra with nine rows of punctures in contrast to those of P. consimilis which he described with ten rows of punctures [both species have elytra with 11 rows of punctures]. In that pioneer period, this species common in central Europe was also described as Donacia rufipes by Olivier (1791), Donacia discolor by Hoppe (1795), and Donacia variabilis by Kunze (1818), who already mentioned the great variability of this species by its specific name.

Donacia discolor was described by Hoppe (1795). According to Bousquet (2016) this was published on [30] April 1795, but a description of a Donacia discolor had been already published by Panzer on 14 February 1795 (Bousquet 2016). Therefore, Donacia discolor Hoppe was immediately a homonym. Later, both species were assigned to Plateumaris, therefore D. discolor Hoppe remained a homonym.

Plateumaris consimilis orientalis was described by Shavrov (1948) (see Geiser and Geiser 2023), which he thought to represent a subspecies of P. consimilis, but it resulted in being synonymous with P. weisei (see at P. weisei below for further explanation).

Pronotum cordate, anterior tubercles slightly convex. Upper side with metallic lustre in varying colours, antennae, and legs at least partly reddish brown. Elytra 1.5–1.8× longer than wide.

Size : 6.0–9.2 mm.

Colour : Very variable, upper side greenish, bluish, cupreous, bronze, or black with metallic lustre, some black specimens almost without metallic lustre (Fig. 5A, B).

Head : Same colour as pronotum. Antennae approximately half the body length or slightly longer, Antennomeres reddish brown at least at the basal part, the apical part can be darkened. ½ A1 ≥ A2, ½ A3 ≥ A2, A4 ≥ A3, A1 ≈ A4, A5 … A11 ≈ A4.

Pronotum : cordate, ahead wider than behind, anterior tubercles only slightly convex, disc uniformly punctate, median line obsolete to fine but distinct.

Elytra : 1.5–1.8× longer than wide, never twice as long as wide, side contours slightly convex, not parallel, elytra rugose and punctulate.

Legs : Colour variation from completely reddish brown to only reddish at the joints, femora basally very broad, metafemora with sharp or broad tooth.

Aedeagus : The shape varies between the short, more rounded form in P. bracata and the elongated acute form of P. rustica (Fig. 5C, D).

The most similar species are Plateumaris bracata and P. rustica: P. bracata has longer elytra, ~ 2× as long as wide and the side contour of the elytra is parallel, not convex (Fig. 4C). Plateumaris rustica has the pronotum not cordate, and disk and tubercles flattened (Fig. 10A). Plateumaris weisei could be mistaken for P. consimilis but their distribution areas hardly overlap.

Although P. consimilis is one of the common Plateumaris species, its larva was not described until 2014 by Medvedev and Muravitsky. The larvae and adults feed on Carex sp. (Cyperaceae). Also, Juncus articulatus (Juncaceae) and Caltha sp. (Ranunculaceae) are mentioned as food plants of adults, on which they feed on the pollen (Rheinheimer and Hassler 2018). Plateumaris consimilis lives in wetlands, fens, near springs, and moor grass meadows. It is more frequent on low calcareous soils, where it is usually the only species of Donaciinae. It is site-loyal and cannot be caught in pitfall traps (with rare exceptions) (Krause 1982; pers. obs.).

Western Palaearctic: mainly continental Europe up to southern Sweden, very rare in south and east Europe and west Siberia. Records exist for: Europe: Albania [first record], Austria, Belarus, Belgium, Bosnia-Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, France, Germany, Hungary, Italy, Latvia, Liechtenstein [new in PalCat], Lithuania, Luxembourg, The Netherlands, North Macedonia [new in PalCat], Poland, Romania, Russia (central part of European Russia), Serbia [new in PalCat], Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine.

Asia: Georgia [first record], Russia (west Siberia), Turkey [new in PalCat].

Albania [first records] • 3 ex.; Qarku i Kukësit, Kula e Lumës, “Albanien Expedition, Kula Ljums”; 18–28 May 1918; H. Goecke 1956 det., E. Geiser 2019 vid.; NHMB [ex coll. Frey] • 1 ex.; Qarku i Kukësit, Gjallica e Lumës, “Albanien Expedition, Gjalica Ljums”; 17–26 Jun 1918; H. Goecke 1956 det., E. Geiser 2019 vid.; NHMB [ex coll. Frey].

Liechtenstein: Walter (1990).

North Macedonia: Gruev and Tomov (1984).

Serbia: Gavrilovic and Curcic (2011).

Georgia [first record] • 2 ex.; Mtskheta, “Transcaucasia, Mazcheta, pr. Tiblisi”; 4–23 Jun 1987; Wrase and Schülke leg.; E. Geiser 2019 det.; NHMB.

Turkey: Ekiz et al. (2020).

Plateumaris consimilis does not occur in the East Palaearctic which has also been confirmed recently by Hayashi (2020). Records from Far East and Japan, e.g., in Goecke (1960) or Warchałowski (2010), are due to records of “Plateumaris consimilis orientalis Shavrov, 1948” which is synonymous with P. weisei (see below). Note that specimens of P. weisei misidentified as P. consimilis were found in collections (pers. obs.).

More than 200 specimens from different localities throughout the distribution area.

Bosnia-Hercegovina: Dol. Tuzla, Bosnia.

Holotype of Plateumaris tenuicornis. Bosnia-Herzegovina • 1 ex.; Bosnia, Dol. [Dolina?] Tuzla; Em. Fritsch leg.; SNMC. Fig. 6A, B. I examined the holotype in 2020 and it is the only specimen known.

Balthasar (1934) described a species Plateumaris tenuicornis from one P. consimilis specimen collected in Bosnia, which he studied in the collection of the Slovak National Museum, Bratislava. The sketches where he compared the pronotum of both species are provided in Fig. 6C, D. Bechyné (1942) published an article about this description. He studied 335 specimens of P. consimilis, mostly from the area which belongs now to the Czech Republic, but also from central France and Podolia, a historic region in Eastern Europe located in the west-central and south-western parts of Ukraine and north-eastern Moldova, but he did not study the holotype of P. tenuicornis (possibly due to the political situation in Europe at that time). He meticulously worked out that all described characters of P. tenuicornis were within the variation range of the characters of P. consimilis. Bechyné published this article in Czech and Latin in a Czech journal, which has been ignored by most Donaciinae specialists. The English translation of the Latin text is now available in Geiser and Geiser (2023).

Askevold (1991) knew neither of the article of Bechyné (1942) nor of the holotype of P. tenuicornis, but he studied the description of Balthasar (1934) and concluded “All character states used by Balthasar are ones that I have also found among P. consimilis” and then declared P. tenuicornis as a probable new synonym. I studied the holotype of P. tenuicornis still stored in the Slovak National Museum in Bratislava (Fig. 6A, B) and I can confirm that Bechyné and Askevold were correct in every detail.

Because Bechyné only indirectly treated P. tenuicornis as a synonym, and because Askevold only suggested that P. tenuicornis should be considered as a probable new synonym, I determined that P. tenuicornis Balthasar, 1934 is a new synonym of P. consimilis (Schrank, 1781) according to Bechyné (1942), supposed by Askevold (1991), and now confirmed based on a study of the type material and original descriptions.

Plateumaris constricticollis: Japan; P. constricticollis babai: Honshu: Niigata Prefecture, Yoshigahira, Shitada-mura; P. constricticollis toyamensis: Tsubura-ike, alt. 690 m, Kamiichi-machi, Naka-niikawa-gun, Toyama prefecture; P. constricticollis chugokuensis: Koiga-kubo, alt. 570 m, Tessei-cho, Atetsu-gun, Okayama prefecture.

Holotype of P. constricticollis: Japan • 1 ♂; Hokkaido, Lake Junsai, N of Hakodate; 43°7'N, 145°6'E; 28–30 Jul 1880; G. Lewis leg.; BMNH 1910-320. The holotype was examined in 2019.

Holotype of P. constricticollis babai: Japan • 1 ♀; Honshu, Niigata Prefecture, Yoshigahira in Mt. Sumon; 25 Jun 1955; K. Baba [leg.]; “P. constricticollis babai Chȗjȏ” M. Chȗjȏ 1959 det.; KUEC.

Holotype of P. constricticollis toyamensis: Japan • 1 ♂; Honshu, Toyama-Prefecture, Kamiichi-machi, Naka-niikawa-gun, Nakanomata, Tsubura-ike; 690 m a.s.l.; 20 Jun 1983; K. Katsura leg; OMNH TI-17.

Holotype of P. constricticollis chugokuensis: Japan • 1 ♂; Honshu, Okayama prefecture, Tessei-cho, Atetsu-gun, Koiga-kubo; 570 m a.s.l.; 13 Jun 1982; O. Tominaga leg.; OMNH TI-18.

Jacoby (1885) described this Plateumaris species as Donacia constricticollis. The details of the location and the date are not tagged to the holotype, and the label contains only “Japan G. Lewis, BMNH 1910-320”. Bates (1883) published the itinerary of G. Lewis’ journey through Japan from February 1880 to September 1881 that contains the exact data. The type specimen was collected at Lake Junsai near Hakodate in south Hokkaido where Lewis sojourned 28–30 July 1880.

Lays (2002) refers to a female type specimen: 1 ♀, “Type”, “Donacia constricticollis Jac.” [no further label data, origin unknown], stored in RBINS. It is unlikely that this “type” specimen could be a paratype or allotype of the series collected in Hokkaido at the same site as the holotype. According to Lays (2002) this specimen belongs to the subspecies P. constricticollis babai, which occurs only in central Honshu. One must keep in mind that some decades ago “type” labels were sometimes added later to specimens in several museum collections without thorough studies.

Specimens of P. constricticollis reveal a remarkable variation in body size and colouration, pronotal disc, and even genital structures. This resulted in the description of four subspecies. Further studies concluded that there were two subspecies in addition to the nominate species, and therefore the other two subspecies names are synonyms (Hayashi and Shiyake 2004). This is also confirmed by several molecular studies (Sota and Hayashi 2007; Sota et al. 2007; Sota et al. 2008; Hayashi and Sota 2014). However, the morphological discrimination of these subspecies is very difficult because of the variations in some key characters.

Chûjô (1959) was the first to describe a subspecies, P. c. babai from Niigata Prefecture. In 1978, Medvedev described P. c. kurilensis from Kunashiri, the southernmost Kurile Island, near Hokkaido. This subspecies was synonymised with P. c. constricticollis by Hayashi and Shiyake (2004: 114). Tominaga and Katsura (1984) described the two subspecies P. c. toyamensis and P. c. chugokuensis, and the latter was synonymised with the former by Hayashi and Shiyake (2004: 116).

The characters common to all subspecies are the following: surface very shiny (Fig. 7), dorsal colouration variable, bronze brown or dark cupreous, black, blue, or green, pronotum cordate, slightly longer than broad, anterior tubercles prominent, elytra regularly and strongly punctate, metafemora with blade-like tooth. It looks similar to a glossy P. consimilis that does not occur in the East Palaearctic region.

Size : 6.6–11.9 mm.

Plateumaris constricticollis and its subspecies have been thoroughly studied by Japanese colleagues, with detailed descriptions of their morphological characters and their variations, as well as phylogeny, biogeographical history, biology, and molecular analyses (Tominaga and Katsura 1984; Hayashi 2002, 2020; Hayashi and Shiyake 2004; Hayashi and Sota 2014). The three subspecies and their distinguishing characters are described in the section “Identification Key”.

The similar species Plateumaris weisei is not shiny or glossy, its pronotum not cordate, and the legs are longer and slenderer.

Sota et al. (2007) analysed the geographic variation in body size and ovipositor dimensions in three subspecies in different climatic conditions and on different host plants, and reported a significant correlation of the body size and ovipositor size with snow depth. The larvae feed on Carex sp. (Cyperaceae) (Narita 2003). Cocoons of P. c. babai were also found on roots of Phragmites australis (Poaceae), Carex thunbergia, and Carex ampliata. Eleocharis sp. is recorded as a larval host plant for P. c. toyamensis (Sota et al. 2007).

Plateumaris constricticollis is endemic to the Japanese Archipelago (Hokkaido, Honshu, and Kunashiri).

Plateumaris constricticollis constricticollis: southernmost Kurile Island Kunashiri, Hokkaido and northern part of Honshu until prefecture of Yamagata (Medvedev 1978; Tominaga and Katsura 1984).

Plateumaris constricticollis babai: Honshu: prefectures Fukushima, Niigata, Nagano, Gunma, Tochigi, Ibaraki, and Chiba.

Plateumaris constricticollis toyamensis: Honshu: prefectures Toyama, Gifu, Ishikawa, Aichi, Hyogo, and Okayama.

Approximately 60 specimens from Japan.

Plateumaris roscida: Russia, Transbaikalia (Zabaykalsky Krai): Tschita; Plateumaris annularis: Russia, Far East, Khabarovsk Krai, Nikolayevsk-on-Amur.

Holotype of P. roscida: Russia • 1 ♂; East Siberia, Transbaikalia, Tschita; ZMHB. Label text: “Typus [red]// roscida m. //coll. J. Weise //Zool. Mus. Berlin //Holotype ♂ Plateumaris roscida Weise [red]//Plateumaris roscida Weise det. I.S. Askevold 1989”.

No location label is tagged to the holotype, but the type locality “Tschita” is indicated in the original description by Weise (1912). The holotype was examined in May 2023.

Holotype of Plateumaris annularis: Russia • 1 ex.; Far East, Khabarovsk Krai, Nikolayevsk-on-Amur, “Amur region, Chabarowsk, Nikolajewsk”; L. Graeser leg.; depository unknown. At first stored in coll. W. Koltze, current depository presumably SDEI, but needs confirmation.

Weise (1912) described Plateumaris roscida (see Geiser and Geiser 2023) based on a specimen from Tschita. He obtained it from Johann Nepomuk Ertl (1860–1925, Munich, Germany), a dedicated beetle collector who had connections to missionaries. This specimen was presumably collected during a journey to China.

Reitter (1920) published an identification key for Palaearctic Donaciinae. In a footnote to P. sericea he described P. annularis from Russia, Far East, Amur region, Chabarowsk (krai), Nikolajewsk, coll. Koltze (see Geiser and Geiser 2023). Reitter did not mention in the description that this P. annularis is armed with a prominent metafemoral tooth, but he provided this information indirectly two paragraphs later when he contemplated if P. obsoleta could be the same species as P. annularis. He also described that, in contrast, P. obsoleta has completely dark legs and the posterior femora are practically unarmed, or only bluntly angled. This description and further notes in Reitter (1920) match completely with the characters of P. roscida.

Kolossow (1930: 29) synonymised P. annularis with P. roscida with the laconic line “Plateumaris annularis Reitt. (1920) = Pl. roscida Weise (1912)”. Goecke (1957a) studied a specimen from ZSM, labelled “Samml. Ertl” [= collection of Ertl] and “Pl. roscida n. sp. Wse” in the handwriting of Weise. He also examined four specimens from the then “Deutsches Entomologisches Institut Berlin” (now SDEI) labelled “Pl. annularis Reitter”, one of them labelled “Nikolajewsk, Graeser” and “Pl. annularis Rtr., Chabaroska, Weise” and another two specimens labelled “Pl. annularis” without location labels. All four specimens were labelled as “Type”. He then compared the P. roscida specimen with the P. annularis specimens and confirmed the statement of Kolossow (1930) that they all belong to P. roscida.

Askevold (1991) studied other specimens from Russia and north China identified as P. annularis and confirmed that they belonged unambiguously to P. roscida. He also suggested that P. caucasica may be synonym of P. roscida because of the description of Zaitzev (1930), but he conceded that the geographic distance between the Caucasus and Transbaikalia caused a problem.

Upper side bronze, bluish, or purplish, flat-lustrous, habitus similar to P. sericea, antennomeres reddish basally and darkened apically, pronotum with flattened anterior tubercles, femora reddish on basal half and dark on apical half. Aedeagus with a conspicuous elongated peak.

Size : 6.7–9.7 mm.

Colour : Bronze or dark with bluish or purplish lustre.

Antennae : Slender, annulated, antennomeres basally rufous, apical dark or metallic, A2 < A3 < A4.

Pronotum : Almost quadratic or slightly longer than wide, anterior tubercles flattened, disc coarsely and closely punctate with fine wrinkles, median groove narrow or indistinct, in posterior part short and slightly deeper, then forked into two horizontal grooves near the bottom line.

Elytra : Oblong, with shallow impressions, coarsely and densely rugose on most of surface, punctures regular, strong, and deep, interstices wrinkled, interstices ~ 2–4× puncture diameter.

Legs : In most specimens the femora are reddish on basal half and dark metallic on apical half, tibia reddish with dark parts, tarsomeres dark or with reddish basal part. Some specimens with entirely reddish legs. Metafemora with prominent, thorn-shaped tooth in most specimens.

Pygidium of females with an apical notch, males broadly emarginate.

Aedeagus : Median lobe with a conspicuous elongated peak, cap of tegmen with a deep apical notch (Fig. 9).

Two similar species are Plateumaris sericea and P. shirahatai which differ: in P. roscida the pronotum and its tubercles are flattened, legs with large reddish parts, and the aedeagus has a conspicuous elongated peak.

Bieńkowski 2014 mentions: Carex sp. (Cyperaceae) as host plants. The larva has not yet been described.

East Palaearctic: East of Lake Baikal to Far East, the Sakha (Yakutia) Republic, Amur region in Russia and north-east China (Harbin, Heilongjiang). Records exist for Asia: northern China (Heilongjiang, Inner Mongolia) [new in PalCat], Russia (East Siberia, Far East).

China – Heilongjiang • 1 ex.; Harbin; 3 Jul 1952; E. Geiser 2021 det.; BM1953-715, (BMNH). • 2 ex.; Xinkai (Khanka) Lake, Bathing beach area; 45°21'52"N, 132°18'55"E; 11 Jun 2018; among strandline detritus; R.B. Angus, F.L. Jia, Z.L. Liang leg., E. Geiser 2021 det.; BMNH.

China: Heilongjiang and Inner Mongolia: Askevold (1991).

More than 30 specimens from different localities throughout the distribution area.

Germany, surroundings of Berlin [Kunze, 1818: 31: “in der Gegend von Berlin”].

Type specimens missing.

Kunze (1818) described four new Donacia species (see original text and translation in Geiser and Geiser 2023) which in fact belong to one single Plateumaris species (Askevold 1991 in part). The name Donacia rustica was described first in this publication, so planicollis, pallipes, and affinis are now synonyms.

Some authors, like Jolivet (1970) and Borowiec (1984), cited the authority of P. rustica as Schüppel (1818, in Kunze 1818) but this is inaccurate since Kunze (1818) wrote after the description: “D. rustica Schüppel in litt.” Therefore, the suggestion is there that the name is derived from J. Schüppel (Berlin), but Kunze actually described this species and published it. The unambiguous authority of P. rustica is Kunze; therefore, D. rustica (Schüppel, 1818) is a nomen nudum. Note that there is no publication of “Schüppel (1818)”.

The names P. abdominalis Bedel, 1891 and P. (Donacia) abdominalis Olivier, 1795 [1800 is correct, see above for P. bracata] were erroneously attributed to P. rustica. The name P. abdominalis is frequently mentioned as a synonym for P. rustica or P. affinis as occurs in the key by Jacobson (1892): “abdominalis Oliv.” with P. affinis as its synonym. Clavareau (1913) defined “abdominalis Bedel” as synonymous with P. affinis and this was followed by Reitter (1920), Winkler (1930), Goecke (1960), and Jolivet (1970); the latter also mentioned “abdominalis Olivier” as synonymous with P. bracata, but Olivier did not describe it [see above for P. bracata]. Also, Bedel (1891) did not describe P. abdominalis; in his list of the Coleoptera of the Seine basin he mentioned P. abdominalis Olivier, together with the synonyms affinis Kunze, 1818 and [sic!] fusca Zschach, 1788 (synonymous with P. bracata). Therefore, P. abdominalis Bedel is a nomen nudum, a misidentification or misinterpretation by Bedel, but not a synonym of P. affinis.

Donacia affinis was also described in Kunze (1818) (see Geiser and Geiser 2023). Goecke (1943) suggested that P. affinis should be considered synonymous with P. rustica. Askevold (1991: 37) synonymised it after examination of ~ 250 specimens from various locations in Europe. These beetles are typically separated in keys by the colour of the antennae, legs, and ventral side, and by the metafemoral tooth size, but these are highly variable characters among many Donaciinae (pers. obs.). In fact, the aedeagi of these two “species” are indistinguishable.

Plateumaris forojulensis was described by Gortani (1906) as aberration.

Donacia fusca was regarded as synonymous with P. affinis, but it is a nomen oblitum (Jolivet 1970).

Plateumaris pallipes was assigned as a synonym of P. affinis and P. planicollis as a synonym of P. rustica. As the original descriptions of Kunze (1818) show, all characters are within the variation range of the typical characters of P. rustica (Geiser and Geiser 2023).

Plateumaris picipes was described by Weise (1898) as a variation (Geiser and Geiser 2023). It refers to specimens with at least very dark femora up to very dark legs. Albeit the basal joints of the femora are always reddish.

Upper side mostly metallic, antennae and legs entirely or partly reddish brown. It has a very smooth and the most flattened pronotum of all Palaearctic Plateumaris species (Fig. 10A).

Size : 6.5–9.0 mm.

Colour : Upper side bronze or black with greenish, bluish, or purplish metallic lustre, colour of pronotum and elytra mostly the same but can also differ significantly. Antennae and legs entirely or partly reddish brown.

Head : Frons with deep or shallow groove, longitudinal calli distinctive or flattened.

Antennae : Filiform, each antennomere yellow or reddish at the basis, darkened at the apex, extent of darkened zone very variable, 2^nd antennomere 2–3× smaller than other antennomeres which are approximately equal in length, only the 3^rd antennomere is sometimes slightly smaller than the others: (2–3)× A2 = A1 = A4 … A11; A3 ≤ A4.

Pronotum : Almost quadratic, only at the basis slightly constricted, with flat disc and indistinct anterior tubercles; surface shiny or alutaceous, disc smooth with small shallow dots, more or less densely dotted, median line varies from imperceptible to distinctive.

Elytra : Punctures very delicate, interstices with slight transversal rugae, interstices 2–4× puncture diameter. Ratio of elytral length to width: 1.7–2.0.

Legs : Yellow reddish, sometimes partly or almost entirely darkened, piceous, but always with reddish joints (var. picipes Weise, 1898). Femora basally broad, metafemoral tooth very variable, mostly prominent, in some (mostly female) specimens very small or imperceptible. There is no geographic correlation concerning the size of the tooth.

Aedeagus : Median lobe distinctly elongated, apex acute (Fig. 10B).

There are two similar species. Plateumaris consimilis has the pronotum distinctly cordate and the disc is not flattened. The pronotum of P. weisei is trapeziform and slightly longer than wide. In the territories where their distribution areas are overlapping (European part of Russia) it can be distinguished from P. weisei by the quadratic shape of the pronotum.

Also, the aedeagi of these species are clearly different (compare Fig. 10B with Fig. 17B, C, E).

The larvae are oligophagous on Carex sp. and other Cyperaceae. Adults feed on leaves and stems, not on pollen (Rheinheimer and Hassler 2018). For identification of the larvae see Steinhausen (1994) and Bieńkowski and Orlova-Bieńkowskaja (2004). Although P. rustica is widespread in the West Palaearctic region and there are many of its food plants available, it is rather rare suggesting that it needs not only wetland with Cyperaceae but also additional ecological conditions.

West Palaearctic region: throughout Europe, further in Algeria, Turkey, Iran, and west Siberia. Records exist for Europe: Austria, Belarus, Belgium, Bosnia-Herzegovina [new in PalCat], Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Great Britain, Hungary, Ireland, Italy, Crimea [new in PalCat], Latvia, Liechtenstein, Lithuania, Luxembourg, Montenegro [first record], The Netherlands, Norway, Poland, Romania, Russia: northern, central, and southern parts [new in PalCat] of European Russia), Serbia [new in PalCat], Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine.

North Africa: Algeria.

Asia: Iran [first record], Russia (west Siberia), Turkey [new in PalCat].

Bosnia-Herzegovina: Mohr (1966b).

Crimea: Listed in Catalogue: Beetles of the Krym (pers. comm. S. Mosiakin 2019).

Montenegro • 11 ex.; Poljane north-west of Podgorica “Pojane”; P. rustica E. Geiser 2019 det.; NHMB [ex coll. Breit in coll. Frey]. Remark: Some specimens were previously identified as P. forojulensis (1 ex.) and P. picipes (4 ex.).

Russia • 1 ex.; Southern European territory, town Samara Nikolayevsky Uyezd; May 1916; Bostanzhoglo leg.; Zoological Museum of Moscow State University, Russia. Remark: private record by Bieńkowski 2016.

Serbia: Gavrilović and Ćurčić (2011), Mohr (1966b).

Iran • 1 ex.; “Persien, Elbrus Gebirge” [Elbrus mountains]; Donacia affinis H. Goecke det., Donacia rustica E. Geiser 2019 det.; NHMB [ex coll. Reitter in coll. Frey].

Turkey • 25 ex.; Bolu Province, Abant Daği [mountain], Abant Gölü [lake]; 1298 m a.s.l.; 31 May 1999; J. Voříšek and J. Kodada leg.; P. rustica E. Geiser 2021 det.; BMNH [ex coll. J. Voříšek]. Bolu province and Kahramanmaraş province (Ekiz et al. 2020).

Plateumaris rustica was unknown from Turkey. There was no record in the “Checklist of leaf beetles of Turkey” (Ekiz et al. 2013). In 2019 I identified 12 specimens from Bolu province stored in Verona (MSNV) and their detailed data are published in Ekiz et al. (2020), including the type location of P. sulcifrons in Kahramanmaraş province. In 2021 I found 25 specimens in the coll. Voříšek which is now stored in BMNH. These specimens were labelled as “P. sulcifrons Weise J. Voříšek det.” but are now relabelled as P. rustica. Also, the aedeagi of these “P. sulcifrons” were identical with the aedeagus of P. rustica.

More than 200 specimens throughout the West Palaearctic region.

Turkey, Kahramanmaraş province: Süleymanlı “Zeytun” [old name].

Holotype : Turkey • 1 ♀; Kahramanmaraş province, Süleymanlı “Zeytun” [old name]; 37°53'N, 36°50'E; O. Staudinger leg. Probably collected in 1872 (see below for details). Depository unknown.

Askevold (1991) declared P. sulcifrons as a “probable new synonymy” for P. rustica. The holotype (♀) is missing but the analysis of the elaborate original description (see Geiser and Geiser 2023) indicates that the characters of P. sulcifrons are within the variation range of P. rustica characters (Table 4). Weise indicates a range of [body] length: 8–9 mm and colour variation in the antennae and legs. This suggests that he had examined more than one (female) specimen. Since 1900 the name P. sulcifrons is mentioned in almost all catalogues and identification keys for the (West) Palaearctic, but no new records were published.

Besides, there was a confusion about the locus typicus. Weise (1900) published only: “Zeitun (Staudinger)”. This sparse note of the collection site led to misinterpretations: “Zeitun” is correctly assigned to Asia Minor (Reitter 1920; Winkler 1930), but it was misinterpreted by Goecke (1960) as “Żejtun”, a town in the east of Malta. Henceforward it was mentioned as a species from Malta (Jolivet 1970; Borowiec 1984; Askevold 1991; Silfverberg 2010; Warchałowski 2010). This location error confirmed the opinion that P. sulcifrons is probably endemic to Malta, therefore missing further records were less suspect.

Otto Staudinger (1830–1900) was a German entomologist who went on numerous collecting trips or promoted them, but insects were not collected in Malta, neither on his own journeys nor on his commissioned trips. In 1872 he visited the Cilician Taurus (Anonymous 1901; Wikipedia [05.10.2022]). Therefore, “Zeitun” mentioned in Weise (1900) is actually “Zeytun” district (now Süleymanlı) of today’s Kahramanmaraş province of Turkey (Ekiz et al. 2020). Different spellings and change of geographical names also did not help to clarify this case.

Unfortunately, the first description does not indicate where these specimens are stored. It is unlikely that Weise returned the type(s) to Staudinger, who was then working on his Lepidoptera Catalogues in his last years. Weise’s private collection and especially the Chrysomelidae part are stored in the Museum für Naturkunde in Berlin (ZMHB), but no Plateumaris specimen labelled “sulcifrons” could be found there, despite the search by J. Frisch in 2019. I screened the Plateumaris collection in 2023 but found no specimen that could be considered the type.

Like other species, where only the type specimen is known, P. sulcifrons was suspected to be a synonym of a well-known species. Weise wrote that it is similar to P. rustica and P. affinis. Askevold (1991) synonymised P. affinis with P. rustica. He noticed that the characters Weise mentioned are typical for P. rustica and suggested that P. sulcifrons may be conspecific. Warchałowski (2003) treated P. sulcifrons also as synonym to P. rustica in his key of the Chrysomelidae of the Europe and the Mediterranean area. However, he treated it as valid species, although doubtful, in his key of the Chrysomelidae of the Palaearctic region (Warchałowski 2010). In Silfverberg (2010) it was listed as valid species from Malta. The locus typicus was corrected to Turkey in Löbl and Smetana (2013).

Unfortunately, I could not examine the type specimen. To confirm the arguments of Askevold (1991) with more details, the characters mentioned by Weise (1900) are compared with the characters of P. rustica in Table 4.

The characters which should distinguish P. sulcifrons from P. rustica are either the same or within the variation range of P. rustica. Therefore P. sulcifrons is a synonym of P. rustica. This was also mentioned in Ekiz et al. (2020) and in Geiser and Bezděk (in press), but without the reason provided here.

Because Linnaeus described sericea (Leptura) in 1758 no type specimen was designated. He stated that it “occurs in Europe” which is correct.

Plateumaris sericea exhibits the highest variability in colour among Donaciinae. The upper side colour is metallic and can be green, golden green, blue, purple, red, violet, bronze, black and all shades in between. This is one of the causes so many “variations” were described which were often used like subspecies names. Additionally, throughout the whole distribution area, some specimens show a reddish base at the antennomeres. Also, few specimens exist with a reddish part near the joints of the femora, tibiae or tarsomeres. In (most) identification keys P. sericea is characterised by “antennae and legs entirely metallic“, which is usually correct. Only in recent keys it is mentioned that there can also be reddish parts at some joints. Therefore, these “not entirely metallic” specimens supported the idea that specimens with a reddish spot belong to a different species or at least subspecies. I examined many specimens from the whole distribution area and determined their morphologic characters inclusive of the aedeagus shape are within the variety range of P. sericea.

In large European collections, where Asian specimens are stored, many of these Asian specimens show a red base of their antennomeres. Perhaps, these specimens were preferentially collected and stored whereas “entirely metallic“ specimens were considered as common and not worth keeping.

The correct data of the first description is Leptura sericea (Linnaeus, 1758): 397, and not “Linnaeus, 1760: 196” as it was printed in Silfverberg (2010: 358). See explanation in section “Genus Plateumaris C. G. Thomson, 1859, Taxonomic history and synonymies” and in Geiser and Geiser (2023).

The genus name Donacia was erected later in 1775 by Fabricius. There he described Donacia crassipes and Donacia simplex and assigned Leptura aquatica L., 1758 to the genus Donacia, but, significantly, he did not change the genus name of Leptura sericea.

Plateumaris asiatica was described as Donacia asiatica by Faldermann (1837) from “Persien” (today’s Iran) and never found again. It was synonymised with P. sericea by Kolossow (1929).

Plateumaris caucasica Zaitzev, 1930: syn. nov., see below.

Plateumaris discolor kratochvili f. coelicolor was described by Bechyné (1945) based on a series of specimens he collected from Přybyslav (central Bohemia). Therefore, coelicolor is a published but infrasubspecific name.

Plateumaris discolor discolor f. cupraria was described by Bechyné (1945) in contrast to P. discolor kratochvili f. isocupraria (see below) but both are infrasubspecific names.

Plateumaris discolor (Panzer, 1795): confirmed synonym, see below.

Plateumaris imitatrix: This name with the author “Apfelbeck” can be found on several museum specimens from Bosnia-Hercegovina (HNHM, coll. Frey in NHMB, SDEI), but a description was never published, therefore P. imitatrix is a nomen nudum. Viktor Apfelbeck (1859–1934) was a former curator of entomology at the National Museum of Bosnia and Herzegovina, Sarajevo. He labelled several specimens from the Balkans with new names which he regarded as new species. Some of them he described later, some of them not. Nevertheless, some of these specimens were also stored in other museums and can be found nowadays. Goecke (1942a) examined one specimen stored in those days in “Deutsches Entomologisches Institut” in Berlin-Dahlem (now SDEI) and identified it as P. sericea unambiguously. I examined three specimens of “P. imitatrix” in HNHM and one in NHMB which are also clearly P. sericea. Presumably, the reddish base of the antennomeres tempted Apfelbeck to regard it as a new species.

Plateumaris intermedia was described by Apfelbeck (1912) on page 239 and not on page 238 in Latin and Serbian (Geiser and Geiser 2023). It was synonymised with P. sericea by Goecke (1942b) who examined a specimen labelled “cotype” from Livanskopolje near Livno (Bosnia) stored in those days in “Deutsches Entomologisches Institut” in Berlin-Dahlem (now SDEI).

Plateumaris discolor kratochvili was described by Bechyné (1945) as a new subspecies in contrast to P. discolor discolor. Both subspecies live in the same habitat. Therefore, they could not be subspecies by definition. The characters to distinguish these two “subspecies” are completely within the variation range of P. sericea. I examined a specimen from Drholec (southern Moravia Czech Republic) leg. et det. Bechyné as P. discolor kratochvoli Beychné, 1945, ex coll. Roubal (SNMC) which is unambiguously P. sericea.

Plateumaris discolor kratochvili forma isocoelicolor, also the forma isocupraria, forma isolacordairei, forma isopurpuricena and forma isoviolacea were described by Bechyné (1945) based on a series of specimens from Přybyslav (central Bohemia) collected by Bechyné. All these form names are infrasubspecific.

Perris (1864) described Donacia lacordairii based on a specimen from Spain (Geiser and Geiser 2023). He allocated it to the same group (“dans la mème division”) as Donacia sericea. It was later regarded as an aberration of P. discolor (Winkler 1930; Balthasar 1934) or as a variation or subspecies P. discolor lacordairii (Silfverberg 2010). Askevold (1991) examined the endophallus of specimens from Spain which are assignable to P. lacordairii. He found it typical for P. sericea from other regions and therefore synonymised it with this species. I examined 31 specimens from BMNH and I agree.

Plateumaris levigata was described by Csiki in 1953 as an aberration of P. sericea.

He wrote: “Plateumaris sericea ab[erratio]. levigata[sic!] nom[en]. nov[um]. pro violacea Gyll. (nec Pall., nec Hoppe)“. Plateumaris “levigata” is not a spelling error although “laevigata” is more common, but both spellings were used in classical Latin for the word “smoothed”, so “levigata” is correct. Anyway, this is an infrasubspecific name.

Plateumaris micans was described as Donacia micans by Panzer in 1795 and not in 1796 according to Alonso-Zarazaga and Evenhuis (2017).

Plateumaris nipponensis was described by Nakane (1963) from Kamikochi, Nagano (Japan). He assigned it closely to P. sericea but listed several relative characters (“more shining”, “relatively shorter”) which fit easily in the variability of P. sericea. It is regarded as subspecies in Warchałowski (2010) and as a synonym in Hayashi (2020) to P. sericea.

Plateumaris nymphaeae: Fabricius (1792) spelled Donacia nympheae in his original description, but this original spelling was an inadvertent error. According to ICZN 1999 (Art. 32.5.1) it has to be spelled nymphaeae as it was applied in Silfverberg (2010).

Plateumaris obsoleta Jacobson, 1894: questionable synonym, see below in P. shirahatai.

Plateumaris palustris was described as Donacia palustris by Schilling in 1838 on page 99 and not in 1837 on page 104. It is a homonym because Herbst (1784) described a Donacia palustris which is now synonymous with P. bracata.

Plateumaris discolor kratochvili forma pseudoviolacea and forma purpuricena were described by Bechyné (1945) based on a series of specimens from Přybyslav (central Bohemia) collected by Bechyné. All these form names are infrasubspecific.

Plateumaris sibirica (Solsky, 1871), confirmed synonym, see below.

Plateumaris socia was described by Chen (1941) based on three specimens from Chekiang (Zhejiang). In Silfverberg (2010) it is stated as a synonym to P. sericea sibirica. Askevold (1991) considered it a probable new synonym and Hayashi (2020) a synonym of P. sericea. The description of Chen (1941) mentions only characters which are clearly within the variation range of P. sericea, to which this species “is very closely allied”. It is also interesting that Gressitt and Kimoto (1961) mentioned in their key of the Chinese species not P. sericea (which occurs in China) but P. socia, separated from the other Chinese Plateumaris species by typical characters of P. sericea.

Plateumaris sericea slovacica Balthasar: In the coll. generalis in SNMC two specimens are stored which are labelled “Čeklís, Slovensko, Plateumaris sericea slovacica det. V. Balthasar, Typus n[ova]. ssp.” which I identified as P. sericea. I assume that Vladimir Balthasar (1897–1978), who described other species and subspecies of Plateumaris (Balthasar 1934) intended to describe these specimens as a new subspecies but never did. Therefore, P. sericea slovacica is a nomen nudum.

Plateumaris discolor ab. tatrica was described by Balthasar (1934) based on one or several specimens (the number is unclear) characterised by a dark purple pronotum and dark violet-blue elytra, collected by Al. Procházka, from Štrbské pleso, High Tatras, Slovakia. Anyway, this is an infrasubspecific name.

Plateumaris violacea was described by Hoppe (1795) as Donacia violacea, but this is a homonym to Plateumaris violacea (Pallas, 1773), originally described as Leptura violacea, which is synonym with P. bracata.

Csiki described 1953 “Plateumaris sericea ab[erratio]. viridis nom[en]. nov[um]. pro micans Panz. (nec Hoppe)“, but that does not matter because this is an infrasubspecific name.

Plateumaris sericea has the largest distribution area of all Plateumaris species. It is no surprise that it is also genetically very variable (Hendrich et al. 2015), which is shown also in the variability of the morphological characters. Additionally, to the colour variations mentioned above, P. sericea also varies in the shape and microstructure of the pronotum. While many Donaciinae species can be characterised by a typical shape of the tooth on the metafemur, P. sericea can show no tooth at all, or a very prominent sharp tooth and all shapes in between. Even the aedeagus varies in shape.

Legs and antennae usually entirely metallic, some specimens with reddish parts near the joints; pygidium of females rounded, in some specimens slightly emarginate, that of males emarginate; apex of median ejaculatory guide rounded.

Size : 6.5–10.5 mm.

Colour : Plateumaris sericea shows the greatest colour variety among all Donaciinae species: The whole beetle can be bronze, green, blue, black, cupreous, purple, red, yellow, and all shades in between. Antennae and legs are mostly completely metallic, but there are some specimens with red base of the antennomeres and even with red parts of the legs, usually at the tibiae or tarsomeres.

Head : Same colour as pronotum, supraocular furrow indistinct; vertex with a median line, antennomeres always apically darkened, either completely dark metallic or the basal part reddish to varying degrees, A3 slightly longer than A2, A4 2× as long as A2 in most specimens. A3 ≥ A2, A4 = 2× A2.

Pronotum : Outline more or less quadrate, in some specimens longer than wide; anterolateral tubercles prominent but sometimes flattened, the disc varies from alutaceous and impunctate to finely or coarsely punctate with deep transverse wrinkles, the median line can be clear and deep or only a very shallow furrow.

Elytra : Disc rugose, rows of punctures, shape, and apex typical like in other Plateumaris species.

Legs : Entirely metallic and same colour as upper side. Rarely, some specimens show reddish parts near the joints, mostly on the tibiae or tarsomeres, metafemora of most specimens with a prominent, blade-like tooth, but some specimens with an indistinct or without any tooth.

Pygidium : Emarginate in males, usually rounded but sometimes shallowly emarginate in females.

Aedeagus : Examples of its variability are shown in Fig. 11D, E.

There are no reliable external characters to distinguish P. sericea from P. shirahatai. The only reliable feature can be found at the endophallus. The apex of the median ejaculatory guide of the endophallus is notched in P. shirahatai (Fig. 12B) whereas it is rounded (Fig. 12A) in P. sericea. The habitus of P. sericea also looks very similar to P. roscida, but the latter always has large red parts on the legs and antennae, and their aedeagi are strikingly different (Figs 9, 11D, E).

Plateumaris sericea feeds on Carex sp., Juncus sp., Eriophorum sp., Scirpus sp. and related plant species. For details and identification of the larvae see Steinhausen (1994), Narita (2003) and Bieńkowski and Orlova-Bieńkowskaja (2004). Plateumaris sericea is the most common Plateumaris species and can be found in many wetland habitats throughout the Palaearctic region. It tolerates a broad range of ecological conditions if it is only wet enough.

Plateumaris sericea has not only the largest distribution area of all Plateumaris species but also of all Donaciinae species. It occurs in the whole Palaearctic region. Any lack of records in some parts of its area is most probably due to a lack of collection trips there. Records exist for Europe: Austria, Belgium, Bosnia-Herzegovina [new in PalCat], Belarus, Bulgaria, Croatia [first record], Czech Republic, Denmark, Estonia, Finland, France, Germany, Great Britain, Greece [first record], Hungary, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Crimea [first record], Montenegro [first records], The Netherlands, North Macedonia [first record], Norway, Poland, Romania, Russia (north, central, and south parts of European territory), Serbia [new in PalCat], Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey [new in PalCat], Ukraine.

North Africa: Algeria [new in PalCat].

Asia: Armenia, Azerbaijan, China (Beijing, Hebei, Zhejiang), Georgia, Iran, Japan, Kazakhstan, Mongolia, North Korea [new in PalCat], Russia (west, east, and south Siberia [new in PalCat], Far East), South Korea [new in PalCat], Turkey [new in PalCat].

Bosnia-Herzegovina: Mohr (1966b) and further new records:

Bosnia • 1 ex,; Livno [north of Buško Jezero]; collected from Cladium mariscus; Donacia imitatrix Apfelbeck [V. Apfelbeck det.], Plateumaris sericea E. Geiser 2019 det.; HNHM • 2 ex.; Jezero near Jaice; on Cladium mariscus; Donacia imitatrix Apfelbeck [V. Apfelbeck det.], Plateumaris sericea E. Geiser 2019 det.; HNHM • 1 ♀; Jezero; 1902; Apfelbeck leg.; Plateumaris intermedia V. Apfelbeck det., Plateumaris sericea E. Geiser 2019 det.; NHMB [ex coll. L. Weber in coll. Frey] • 1 ex.; Alps [Dinaric Alps]; Tomov det., E. Geiser 2019 vid.; HNHM • 1 ex.; Vrelo Bosne [spring of the Bosna river, in Ilidža, west of Sarajevo]; Plateumaris discolor Apfelbeck [det.], Plateumaris sericea I.K. Lopatin det.; HNHM • 1 ex.; Sarajevo, Igman Planina [Igman mountain west of Sarajevo]; 9 May 1930; Dr. J. Fodor leg., J. Bezděk 2017 det.; HNHM.

Croatia • 1 ex.; Pakrac [town in western Slavonia]; Plateumaris discolor ab. lacordairii Z. Kaszab det., Plateumaris sericea E. Geiser 2020 det., HNHM [ex coll. Apfelbeck] • 5 ex.; Plitvice [Plitvice Lakes National Park]; May 1970; [each with a different colour]; E. Geiser 2021 det.; ZFMK [coll. Prof. H. Bick].

Crimea • 1 ex.; Sebastopol; W. Pliginsky [leg.?]; Plateumaris discolor ab. lacordairii W. Balthasar [det.?], Plateumaris sericea E. Geiser 2020 det.; SMNC. Remark: Balthasar (1934) published a small key where he described P. discolor ab. tatrica to distinguish it from P. discolor ab. lacordairii. This is most likely the specimen he examined for this key because it shows exactly the same characters that he mentioned there.

Greece • 1 ex.; Thessalia, Pindos mountains, Dessi, Kalambaka, Pertouli, 1110 m; 23. May 2001; A. & F. Riedel leg.; E. Geiser 2023 det; SMNS.

Montenegro • 1 ex.; Crna Gora, Žabljak; 18. Jul 1934; Dr. J. Fodor leg.; J. Bezděk 2017 det.; HNHM • 7 ex.; Žabljak; 4 Jul. 1983; W. Grosser leg.; E. Geiser 2021 det.; BMNH [ex coll. Voříšek].

North Makedonia • 6 ex.; Delčevo; 3 Jun. 1982; I. Rozner leg.; J. Bezděk 2017 det.; HNHM.

Serbia: Gavrilovic and Curcic (2011).

Turkey: Many records from European and Asian territory in Ekiz et al. (2020).

Algeria: Goecke 1957b.

North Korea: Cho and An (2020).

South Korea: Cho and An (2020).

Russia (South Siberia): Gus’kova et al. (2018).

More than 500 specimens from different localities, labelled as various species or subspecies throughout the distribution area.

Russia: Stavropol and Dagestan.

Type series : Russia • 4 ex; Ciscaucasia, Stavropol; Apr 1905; DM Maljuzhenko leg.; Russia • 5 ex; Daghestan, Chasav-jurt; E. Koenig leg.

According to Zaitzev (1930) these specimens were stored in the “Collection of the Georgian Museum”. The currently depository is unknown.

Geiser (in press) and Geiser and Bezděk (in press) treated P. caucasica as a synonym of P. sericea “based on study of comparative material, descriptions, and of biogeographical research“. Zaitzev (1930) described a new species Plateumaris caucasica (see Geiser and Geiser 2023) based on reddish parts of the antennomeres and legs. Additionally, he stated as different characters: “a more rugose pronotum (almost like P. discolor)” and “compared with P. discolor more slender antennae, the fourth antennomere which is twice as large as the second”. Also, he stated, it is a “intermediate species between sericea L. and discolor Panz.”

As I explained in “General remarks on synonyms of Plateumaris sericea” above, this is a typical example of establishing a new “species” on colour characters. The other mentioned “different” characters are completely within the variation range of P. sericea or characteristic of this species. The morphology of the aedeagus is also completely within the variation range of P. sericea. In the same area also typical P. sericea (that is: with completely metallic antennae and legs) could be found, the colour variation form “P. sericea caucasica” could not even be a subspecies.

Zaitzev assumed that Plateumaris caucasica is also “very close” to P. annularis, because both have a red base at their antennomeres and legs which are partly reddish brown. To the credit of Zaitzev it is necessary to mention that he had doubts if P. caucasica is really a new species or a synonym to P. annularis. He suggested to treat it as a new species until further knowledge is available about the East Siberian Plateumaris species.

Plateumaris annularis was synonymised by Kolossow (1930) with P. roscida (see there for details). Askevold (1991) suggested that “Donacia caucasica (Zaitzev) (1930: 11)” [sic! it was described it as Plateumaris and not as Donacia] is a “possible new synonym” to P. roscida. He argued that both have the red base of the antennomeres and the description of Zaitzev agrees well with specimens of P. roscida, but he had doubts because P. roscida is known only from Asia east of lake Baikal whereas P. caucasica only occurs in the Caucasus region.

First, it is actually biogeographically implausible that these two species should be synonyms. Second, the pygidium is emarginate in P. roscida and not emarginate in P. caucasica in both sexes. Third, the aedeagi of P. roscida and P. caucasica are strikingly different. For the median lobe of P. roscida see Fig. 9. The median lobe of P. caucasica fits well into the variation range of P. sericea (Fig. 11D, E). Therefore P. caucasica is a synonym of P. sericea.

Bieńkowski (2014) stated in his identification key at P. sericea: The taxonomic status of the subspecies caucasica and sibirica needs further studies. This has been done here for caucasica and sibirica (see below).

More than 30 specimens from the Caucasus region (north and south) labelled as “P. caucasica”, “P. sericea caucasica” or “P. roscida” which were all clearly P. sericea.

Germany.

The holotype is unknown.

Plateumaris discolor was described by Panzer (1795) as Donacia discolor (Geiser and Geiser 2023), but the morphological variability of P. discolor is within the range of the variability of P. sericea. It was finally synonymised with P. sericea by Askevold (1991) by examination of the endophalli from P. discolor and P. sericea specimens which showed constant characters throughout their distribution area (Fig. 12a), but some authors continue to regard P. discolor as a species propria (Silfverberg 2010; Bieńkowski 2014; Rheinheimer and Hassler 2018); therefore, further arguments are discussed below.

Several characters are used to distinguish P. discolor from P. sericea. The first are the antennomeres: in P. discolor A3 and A4 are a little bit longer than A2, whereas in P. sericea A3 is 1.5× as long as A2 and A4 is twice as long as A2. In fact, the length of the antennomeres is very variable, therefore the difference between “a little bit” and “one and a half” is not clear.

The second is the pronotum disc: in P. discolor it is more punctured and transversely wrinkled whereas in P. sericea it is very finely sculptured. However, the structure of the pronotum disc varies in both “species” in its sculpture and shows an intermediary form in many cases.

The third is the median lobe of the aedeagus, which is also very variable (Fig. 11D, E). This is shown also in the drawings and pictures in identification keys. Sometimes the aedeagus picture of P. discolor in one key looks most similar to the picture of the aedeagus of P. sericea in another key. When a drawing or photograph was made from different angles of view, the same aedeagus can look different in shape and contour. There exist specimens with “discolor” antennomeres and “sericea” pronotum and vice versa. Also, each shape of the aedeagus can occur with any combination of the antennomere or pronotum characters.

Due to these variations, there are no reliable morphological characters to distinguish P. discolor from P. sericea. Other evidence suggests that they may be separate species: P. discolor is reported to be assigned to acid soil and peat bogs where the larvae develop on Carex, Juncus and related plants, whereas P. sericea prefers various wetland habitats with alkaline soil (Rheinheimer and Hassler 2018). Their larvae feeds on Sparganium sp. and Iris pseudacorus (Bienkowsky, 2014). However, P. sericea has such a large distribution area and is very abundant even nowadays in contradiction to almost all other Donaciinae species, therefore, it is more likely that the food plant is also widespread and abundant. This is the case with Carex or Juncus but not with Sparganium and Iris. In the key to Donaciinae larvae in Japan Narita (2003) mentions Carex dispalata Boott. and Scirpus fluviatilis (Torr.) A. Gray as food plants for the larvae of P. sericea. This is definitely not a confusion with P. discolor because the latter does not occur in Japan. Therefore, the assignment to the food plants in Bienkowsky (2014) contradicts the study of Narita (2003) and is in general not a suitable argument that P. discolor is a separate species.

Molecular studies by Hendrich et al. (2015) and J. Bergsten (pers. comm. NHRS, 23 Jan 2023) indicate that P. sericea is genetically very variable. In molecular phylogenetic trees, specimens identified as P. discolor are resolved in between P. sericea specimens, sometimes in groups and separated from P. sericea groups, sometimes not. It is likely that some of these specimens identified as P. sericea are “some kind of” P. discolor and vice versa, because morphological characters are not reliable to distinguish them. There is another problem: it is possible that P. sericea consists of several cryptic species but P. discolor may not be one of them.

More than 100 specimens labelled “P. discolor” from different localities in Europe.

Russia, Irkutsk.

Solsky (1871) did not indicate the depository. It is unknown if the holotype still exists.

Plateumaris sibirica was described as Donacia sibirica by Solsky (1871) as a new species from Irkutsk which resembles P. sericea (Geiser and Geiser 2023). It was not described as a “variation” as is sometimes cited in the literature. Jacoby (1885: 193) doubted it: “Donacia sericea var. sibirica? Solsky: The dozen specimens obtained at Nikko show scarcely any difference from our European form … Structural differences I can see none.”

Eventually, the original description only mentions characters which are typical for P. sericea. It has been regarded as a synonym to P. sericea by Goecke (1960) and Hayashi (2020), but it is treated as a subspecies in Silfverberg (2010), in Warchałowski (2010), and in Bieńkowski (2014). The latter mentioned that “the taxonomic status of the subspecies P. sericea sibirica needs further studies”.

I examined more than 60 specimens identified as P. sericea sibirica, mainly from the BMNH, NHMB, NMPC and SDEI, and I agree with Jacoby, Goecke and Hayashi that all characters are clearly within the variation range of P. sericea. I could not find any differences compared with European or other Siberian specimens. Therefore, I confirm the decision of Goecke (1960) and Hayashi (2020) that P. sibirica is neither a valid species nor a subspecies, but synonym of P. sericea.

The original description was mostly cited as Solsky (1872). It was described in “Horae Societatis Entomologicae Rossiae” volume 8 comprising the years 1871 and 1872. There it was described in the part of 1871 according to Standfuss and Kerzhner (2004).

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

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.

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.

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.