Plateumaris constricticollis (Jacoby, 1885)

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 constricticollis (Jacoby, 1885)

Fig. 7

Donacia constricticollis Jacoby, 1885: 192.

Plateumaris constricticollis babai Chûjô, 1959: 2.

Donacia constricticollis Plateumaris constricticollis Jacoby, 1885: 192 (= Plateumaris constricticollis kurilensis L. N. Medvedev, 1978b: 83).

Plateumaris constricticollis toyamensis Tominaga & Katsura, 1984: 27 (= Plateumaris constricticollis chugokuensis Tominaga & Katsura, 1984: 28).

Type localities.

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.

Type material.

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.

Taxonomic history and synonymies.

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).

Diagnosis.

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.

Description.

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.

Biology.

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).

Distribution.

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.

Material examined.

Approximately 60 specimens from Japan .

Figures

Figure 7. Plateumaris constricticollis Habitus (photograph by K. Matsumoto). Scale bar: one unit - 1 mm.