Gonarcticus Becker, 1894

Ozerov, A. L. & Krivosheina, M. G., 2015, A review of the genera Cleigastra Macquart, Gonarcticus Becker, Gonatherus Rondani, Hexamitocera Becker, Nanna Strobl, Orthacheta Becker and Spathephilus Becker (Diptera, Scathophagidae) of Russia, Zootaxa 4012 (2), pp. 201-258 : 210-212

Gonarcticus Becker, 1894

Gonarcticus Becker, 1894: 103 . Gender: masculine. Type species: Scatomyza antennata Zetterstedt, 1838 , by original designation.

The world fauna comprises four species, two of them recorded from the Palaearctic, including Russia ( Gorodkov, 1970, 1986).

Gonarcticus species are slender, medium-sized flies, about 5–6 mm long ( Fig. 42 ). Head. Frontal vitta yellow or blackish in upper half and yellow in lower half, frontal plate black, grey dusted. Face, parafacial and gena yellow. Postcranium black completely or black in upper half and yellow in lower half, greyish dusted, covered with yellow hairs in lower half or third, with black postocular setulae and black setae in upper part. Chaetotaxy: 3 orbital, 4–5 frontal, 1 ocellar, 1 inner vertical, 1 outer vertical, 1 postocellar; 1 pair of strong vibrissae and 2–4 pairs of subvibrissae present. Antenna yellow or black. Postpedicel with slightly acute upper apical corner, approximately 2.5–3.0 times as long as wide. Arista black, bare or pubescent throughout its length. Palpus long, yellow completely or darkened apically.

Thorax black, grey dusted. Chaetotaxy of scutum: acrostichals in two rows, prescutellar pair slightly longer than the other acrostichals, dorsocentrals (3–4)+3, intra-alars 1+2, supra-alars 1+2, postpronotals 2, notopleurals 2, postalars 2. Proepisternum with hairs in central part, with 1 seta near lower margin. Proepimeron with 1 seta. Anepisternum covered with hairs in posterior half and with 2–5 black setae along posterior margin. Katepisternum covered with hairs in ventral corner and with 2 or 3 strong setae; in G. arcticus anterior katepisternal seta absent. Anepimeron bare. Scutellum black, grey dusted, with pairs of strong basal scutellar and apical scutellar setae.

Legs usually completely yellow, but in G. arcticus coxae of all legs blackish, tarsi of all legs and fore femur posterodorsally darkened. Fore femur with rows of posterior, posterodorsal and posteroventral setae. Fore tibia with 1–2 posterodorsal, 1–2 anterodorsal and 0–1 posterior setae at middle, and apical setae: 0–1 posterodorsal, 1 dorsal and 1 posterior. Mid femur with row of anterior and posteroventral setae, 2 preapical posterior and 3–4 anteroventral setae on apical half, in G. a rc t i cu s additionally with a row of posteroventral setae. Mid tibia with 1–2 anterodorsal, 1–2 posterodorsal, 0–1 posterior (posteroventral), 0–1 anteroventral setae, and ring of apicals. Hind femur with row of anterior (anterodorsal) setae, with 0–3 dorsal setae on apical third, 1 preapical posterior (posterodorsal) seta, 4–5 anteroventral setae on apical half, and usually with a row of thin posterovental setae. Hind tibia with 2–3 anterodorsal, 2–3 posterodorsal, 0–1 anteroventral, 1 preapical dorsal setae, and apical setae: 1 anteroventral, 0–1 posteroventral, 1 anterodorsal, 0–1 posterodorsal.

Wing tinged with brownish; veins blackish; vein R1 bare or setulose on apical third of dorsal surface. Calypters, margins of calypters, and halteres yellowish.

Abdomen cylindrical, yellow or black, grey dusted, covered with black hairs and setae. Tergites 2–6 each with row of marginal setae. Sternite 4 simple, longer than wide ( Figs 28 , 33, 37 ). Sternites 5 as in Figs 25 , 30, 36 . Surstyli simple and wide, cerci fused ( Figs 26, 27 , 31, 32, 34, 35 ). Ovipositor long, cylindrical, not compressed ( Figs 39– 41 ).

Biology of all species is still unknown.

Figures

FIGURES 39 – 44. Gonarcticus arcticus (Becker) (39 – 43) and Gonarcticus abdominalis (Zetterstedt) (44): 39 — end of female abdomen, ventral view; 40 — same, dorsal view; 41 — same, lateral view; 42 — male, habitus; 43, 44 — distribution maps.

FIGURES 22 – 29. Cleigastra sundukovi Ozerov (22 – 24, 29) and Gonarcticus abdominalis (Zetterstedt) (25 – 28): 22 — male sternites 4 (lower) and 5 (upper); 23, 26 — epandrium, cerci and surstyli, lateral view; 24, 27 — same, dorsal view; 25 — male sternites 5; 28 — male sternites 4; 29 — distribution map. Figures 22 – 24 after Ozerov (2013, Figures 21 – 23).

FIGURES 30 – 38. Gonarcticus antennatus (Zetterstedt) (30 – 33, 38), Gonarcticus arcticus (Becker) (34 – 37): 30, 36 — male sternite 5; 31, 34 — epandrium, cerci and surstyli, lateral view; 32, 35 — same, dorsal view; 33, 37 — male sternite 4; 38 — distribution map.