Gonatherus Rondani, 1856

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 : 215

Gonatherus Rondani, 1856

Gonatherus Rondani, 1856: 99 . Gender: masculine. Type species: Cordilura planiceps Fallén, 1826 , by original designation.

One Holarctic species, Gonatherus planiceps ( Fallén, 1826) , is known in the world.

Gonatherus planiceps is slender, medium-sized fly (4–5 mm long) ( Fig. 45 ). Head. Frontal vitta yellow, frontal plate black, grey dusted. Face, parafacial and gena pale yellow. Postcranium black in upper half and pale yellow in lower half, greyish dusted, covered with yellow hairs in lower half, with black postocular setulae and black setae in upper half. Chaetotaxy: 3 orbital, 7–9 frontal setae in two rows, 1 ocellar, 1 inner vertical, 1 outer vertical, 1 postocellar; 1 pair of strong vibrissae and 2–3 pairs of subvibrissae present. Antenna black, but postpedicel sometimes yellowish at base or more. Postpedicel with slightly acute upper apical corner, in male wider than in female, approximately 2.5–3.5 times as long as wide. Arista black, bare. Palpus long, yellow.

Thorax black, extensively grey dusted. Scutum with following setae and setulae: acrostichal setulae in two rows, prescutellar pair slightly longer than the other setulae, dorsocentrals 3+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 2–3 black setae along posterior margin. Katepisternum covered with hairs in ventral corner and with 2 strong setae (upper posterior katepisternal and lower posterior katepisternal). Anepimeron bare. Scutellum black, extensively grey dusted, with pairs of strong basal scutellar and apical scutellar setae.

Legs usually completely yellow, but sometimes male fore femur with dark stripe posterodorsally and hind coxa blackish. Fore femur with rows of posterior, posterodorsal and posteroventral setae. Fore tibia with 1 posterodorsal, 2 anterodorsal and 1 posterior setae at middle, and apical setae: anteroventral, ventral, dorsal and posterior. Mid femur with row of anterior setae, 1 preapical posterior, 1 preapical posterodorsal and 3–4 anteroventral setae. Mid tibia with 1–2 anterodorsal, 1–2 posterodorsal, 1 posterior (posteroventral), 0–1 anteroventral setae, and ring of apicals. Hind femur with row of anterior (anterodorsal) setae, with 3–4 dorsal (anterodorsal) setae on apical third and 4–5 anteroventral setae on apical half. Hind tibia with 3 anterodorsal, 3 posterodorsal, 0–1 anteroventral, 1 preapical dorsal setae, and apical setae: anteroventral, posteroventral, anterodorsal.

Wing often darkened brownish along anterior margin and around r-m and dm-cu crossveins; veins blackish; vein R1 bare. Calypters, margins of calypters, and halteres yellowish.

Abdomen cylindrical, black, grey dusted, covered with black hairs and setae. Tergites 2–6 each with row of marginal setae. Sternite 4 simple, as long as wide ( Fig. 47 ). Sternite 5 as in Fig. 46 . Surstyli simple and long, cerci fused ( Figs 48, 49 ). Ovipositor long, cylindrical ( Figs 50–53 ). Female segment 7 compressed laterally ( Fig. 52 ). Sternite 7 long, triangular ( Fig. 53 ).

Biology unknown.

Figures

FIGURES 45 – 49. Gonaterus planiceps (Fallén), male: 45 — habitus; 46 — sternite 5; 47 — sternite 4; 48 — epandrium, cerci and surstyli, lateral view; 49 — same, dorsal view.

FIGURES 50 – 54. Gonaterus planiceps (Fallén): 50 — end of female abdomen, ventral view; 51 — same, dorsal view; 52 — same, lateral view; 53 — female abdominal sternite 7; 54 — distribution map.