Eumerus ryzhik Barkalov et Mutin, 2022

Barkalov, V. A. & Mutin, V. A., 2022, Two new species of the genus Eumerus Meigen, 1822 (Diptera: Syrphidae) from Central Asia, Far Eastern Entomologist 461, pp. 24-30 : 26-29

Eumerus ryzhik Barkalov et Mutin sp. n.

https://zoobank.org/NomenclaturalActs/ ABACC63C-F87B-49AF-824A-CAB58AAB9E71

Figs 7‒15

TYPE MATERIAL. Holotype ‒ ♂, Uzbekistan: Derbent , 38°12’ N, 67°01’ E, 1012 m,

12.IX 2017, M. Proshchalykin leg. [ SZMN]. Original label: “ УЗбекистан, Дербент 12‒14 .

09.2017, М. ПроЩалыкин”. Paratypes: 1 ♂, 1♀, the same label as holotype [ FCBV] .

DESCRIPTION. Male. Body length 8,5‒ 8.9 mm, wing length 6.3‒6,5 mm.

laterally; 7 ‒ 10 ‒ E. ryzhik sp. n.: 7 ‒ male dorsally; 8 ‒ epandrium laterally; 9 ‒ hypandrium laterally; 10 ‒ surstylus laterally. Scale bars: 5, 7 = 1.0 mm; 8‒10 = 0.2 mm.

Head. Face black, rather shiny, weakly grey pollinose, with long yellowish-white pile;

head width under antennae about 3,2 times as wide as face. Frons with dense long yellowishwhite pile masking black coloration of chitin. Vertex grey pollinose anteriorly and shining black behind ocellar triangle, with long erect yellowish pile; ocellar triangle isosceles. Occiput shiny dorsally, with yellowish pile. Scapus of antenna black, very short; pedicel bright orange;

basoflagellomere bright orange, with deep transversal groove dividing its into two unequal parts; larger distal part with oval fossa apically ( Fig. 13 ); arista black, thickened basally.

Eyes distinctly dichoptic, with long dense yellow pile; least distance between eyes almost equal to width of basoflagellomere ( Fig. 11 ).

Thorax. Scutum and scutellum weakly punctate, shiny black, with dense erect long yellowish pile. Pleura shiny black, mainly with yellowish pile, except katatergum with short black pile. Coxae and trochanters black, unmodified. Femora black, with yellow apex; pro- and mesofemora with very short black pile anteriorly and long yellow pile posteriorly; metafemur moderately swollen, with a pair of apico-venral rows of weak short setae; its antero-ventral surface with short yellow pile basally and black ones apically. Tibiae mainly black except yellow basal ¼; pro- and mesotibiae, with long yellow pile on the outer surface; vestiture of metatibia shorter, pale basally and black apically. Tarsi entirely black. Wing infuscated in apical half, from anterior margin to basal part of cell CuA 1 and from fork of vein RS and transversal vein bm-cu to vein M 1; basal cells mostly bare of microtrichia.

Abdomen with long erect white pile on lateral sides of tergum II, shorter erect white and black pile on terga III‒IV laterally and short semierect white and black pile otherwhere. Tergum I completely black; tergum II orange-reddish with goblet-like black maculae medially

( Fig. 7 ); tergum III mostly orange-reddish with narrow black vitta baso-medially; tergum IV completely orange. Terga II, III and IV with rather broad oblique grey pollinose maculae,

distinctly visible from posterior view. Sternum IV elevated, with shallow incision ( Fig. 12 ).

Genitalia – Figs 8–10 , 14 .

ventrally; 13 ‒ pedicel and flagellomere laterally; 14 ‒ male genitalia laterally; 15 ‒ abdomen of female dorsally. Scale bars in mm.

Female. Body length 8.5 mm, wing length 6.2 mm.

Similar to male except sexual dimorphism: basoflagellomere bigger, frons broader, vertex with black pile, mesonotum with shorter pile, a less intense infuscated apical part of wing.

DIAGNOSIS. Male of E. ryzhik sp. n. goes to couplet 25 in the key to Palaearctic species of the genus Eumerus (Stackelberg, 1961) , which leads to E. ammophilus Paramonov, 1927

and E. binominatus Hervé-Bazin, 1923 , but it differs from the first by smaller size, scutum without pollinose marks and mainly orange-reddish abdomen ( E. ammophilus has scutum with a pair of grey pollinose vittae on anterior half and dark abdomen with a pair of small yellow-brown maculae on tergum II) and differs from the second by entirely pale pile on face, frons and vertex as well as orange basoflagellomere ( E. binominatus has black pile on frons and under antennae, and brown-red basoflagellomere). The female of E. ryzhik sp. n.

goes to the antithesis 38(37), where the Eumerus palaestinensis Sack, 1949 is located, and differs from latter by wing infuscated and abdominal pattern.

Male of E. ryzhik sp. n. is like to one of Eumerus pilosipedes Gilasian et van Steenis, 2020

and differs from the latter by lack of pollinose vittae on the scutum as well as characters of genitalia. On the contrary, the characters of male genitalia of E. ryzhik sp. n. are closer to

Eumerus grallator Smit, 2019 , E. tenuitarsis Grković & Vujić, 2019 , E. vallicolus Gilasian et van Steenis, 2020 , but the new species differs from listed species by orange flagellomere and other numerous characters.

DISTRIBUTION. The species is known from type locality only: Uzbekostan, Surxondaryo

Region, Derbent Village.

ETHYMOLOGY. The species name is a noun in adjective form the Russian «рыЖик»

and indicates the presence of rufous abdominal coloration.

Figures

Figs 5‒10. Eumerus ssp. 5 ‒ 6 ‒ E. kopetdagicus sp. n.: 5 ‒ male laterally; 6 ‒ metaleg

Figs 11‒15. Eumerus ryzhik sp. n. 11 ‒ head of male dorsally; 12 ‒ sternum IV of male