Platycheirus shantar Mutin, 2021

Mutin, V. A., 2021, A list of hover-flies of Bolshoi Shantar Island (the Sea of Okhotsk) with description of a new species of the genus Platycheirus Lepeletier et Serville, 1828 (Diptera: Syrphidae), Far Eastern Entomologist 431, pp. 1-9 : 3-4

Platycheirus shantar Mutin , sp. n.

http://zoobank.org/NomenclaturalActs/ 01D36F1F-E151-40C0-B425-11B5075873F8

Figs 1–3

TYPE MATERIAL. Holotype – ♂, Russia: Khabarovsky krai, Bolshoy Shantar

Island, southeastern shore of Bolshoe Lake, meadows, 4–7.VIII 2020, leg. O. Kuberskaya and D. Kochetkov [ FCBV].

DESCRIPTION. Male. Body length 8.0 mm. Wing length 7.2 mm.

Head. Lower part of face much protruding, mouth-edge more so than facial tubercle. Face mainly grey pollinose, except the moderately shining surfaces around facial tubercle and under eyes, with mainly pale pile, except a few black near frons.

Frons grey pollinose, with black pile. Frontal triangle near 90⁰. Vertex with black pile. Ocellar triangle equilateral. Antennae black.

Thorax. Mesonotum slightly shiny black due to weakly grey pollinose with two indistinct median vittae reaching half of the scutum, mainly with black pile, except yellow pile antero-medially and laterally. Scutellum with shining black pile, except pale scutellar fringe and a few yellow pile basally. Pleurae grey pollinose and yellow pilose.

Wing membrane microtrichose, rather darkened anteriorly; stigma area and costal cell of the same color. Calypter dark grey, the rim rather black. Halter yellow.

Legs predominantly black, except apex of pro- and mesofemur and basal 1/3

pro- and mesotibia and knee of metaleg brownish-yellow and apical 1/5 protibia whitish as well as two basal protarsomeres in the main dorsally whereas their ventral surface with contrasting pattern ( Fig. 3 ). Pro- and mesotrochanrer with short black dense setae. Profemur mainly with black pile except a few pale pile basally, without regular row of long peculiar setae. Protatibia with posterior longer pile on apical half, the longest of which are approximately 2.5 times tibial width. Protarsus with strong flattened first and second tarsomeres, whitish dorsally with translucent pattern of ventral surface. Basоtarsomere subtriangular, strongly oblique apically,

approximately 2.5 times as wide as apex of tibia, the ratio of length: width as 2.3:

1.6. Second tarsomere subrectangular, three-quarters as wide as first tarsomere and one-quarter as long. Tarsomeres 3–5 are black dorsally and completely darkened ventrally. Mesofemur is mainly with black pile including longer ventral ones.

Mesotibia mainly with black pile, a few long pile on apical half are approximately 3

times as large as tibial width. Metafemur mainly yellow pilose with very long anterior-ventral pile. Metatibia with short golden and black pile. Basotarsomere of the metaleg strongly swollen.

Abdomen muddy black with yellow, grey pollinose maculae on terga II–IV well separated from the lateral margin of the respective tergum; pile mainly pale and longer laterally, except short black pile on terga III-V medially and posteriorly. Pale maculae diffused rather subtriangular on terga III-IV and substantially reduced and almost invisible among the gray pollination on tergum II ( Fig. 1 ).

Female. Unknown.

DIFFERENTIAL DIAGNOSIS. New species belongs to manicatus species-

group and is similar to Platycheirus manicatus (Meigen, 1822) . It could be recog-

nized as the melanistic form of the latter species, but in new species the abdomen is visibly narrower, tergum II is almost square, the width of tergum III is a little bit more than the length, the ratio of the width to length is 11: 9 ( P. manicatus has narrowly oval abdomen, but terga II and III visibly transversal; the ratio of width to length of tergum II as 4: 3). Pattern of ventral surface of basal protarsomeres in new species are more contrasting, black maculae are larger and lateral edging is white; pilose of pro- and mesofemur mainly black (pilose of P. manicatus mainly yellow). Basotarsomere of the metaleg is like the one of P. manicatus .

view; 2 – external appearance, lateral view; 3 – protarsus, ventral view.

DISTRIBUTION. Russia: Shantar Island.

ETYMOLOGY. The name of the species indicates the geographical location of its discovery – the Shantar Islands.

MATERIAL USED FOR COMPARISON. Platycheirus manicatus (Meigen,

1822): UK: Scotland, Linkin Shore , nr. Goldingham, 20. VI 1996, 1 ♂, leg. V .

Mutin ; Norway: Espedal , 780 moh Os: Gausdal, 5.VII 1978, 2 ♂, leg. Tore Nielsen ;

Klepp: Øksnevad, 2.VII 2001, 1 ♂, leg. V. Mutin; Klepp: Orre, sanddunes, 4.VII

2001, 1 ♂, leg. V. Mutin .

Figures

Figs 1–3. Platycheirus shantar sp. n., holotype male. 1 – external appearance, dorsal