Ommatius radamnis, Daniels, Greg, 2017

Daniels, Greg, 2017, Australian species of Ommatius Wiedemann (Diptera: Asilidae) with an anepimeral bristle, Zootaxa 4231 (4), pp. 535-563 : 560-563

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Ommatius radamnis

sp. nov.

Ommatius radamnis sp. nov.

( Figs 4 View FIGURES 4 – 9 , 101–109, 116 View FIGURES 101 – 106 View FIGURES 107 – 116 )

Diagnosis. Sternite 2 with long, erect setae scattered over most of surface.

Type material. HOLOTYPE ♂, AUSTRALIA. Northern Territory . 1 ♂, N.T. 12.45°S 132.53°E / Radon Ck (Rainforest) / 14–16 July 1979 / G. Monteith (Malaise) / (QM Reg. No. T 207017). PARATYPES. Northern Territory GoogleMaps . 3 ♀, same data as holotype (QM).

Description. Male. Body length, 7.9 mm; thoracic length, 2.0 mm; wing length, 5.3 mm. Head. Face gently rounded, protruding beyond eyes in profile and with silvery-white tomentum. Mystax with two vertical rows of long thin bristles, the uppermost 2 or 3 pairs black, remainder white and a with medial row of stouter, white bristles; ventrally admixed with smaller weaker white setae on lower half of face and epistomal margin. Ocellar tubercle with a pair of long erect or proclinate setae and a few smaller proclinate setae anteriorly. Occiput with several long black setae dorsally, weakening and becoming white ventrally. Flagellum about half as long as pedicel and conical. Style with setae in two ranks. Thorax. Ground colour black, lateral pleural sclerites with fine grey tomentum; mesonotum with brownish tomentum, becoming silver-grey laterally; postpronotal lobe with a black area anteriorly which lacks tomentum and with a few long, white setae anteriorly. Acrostichal setae seemingly absent but when viewed in profile setae are visible. Presutural dorsocentral bristles absent; 2 or 3 pairs of postsutural dorsocentral bristles present. Scutellum dorsally with sparse, scattered setae and 2 long marginal bristles. Anepisternum bare, rarely with weak setae posteriorly. Anepimeral seta present. Wing ( Fig. 116 View FIGURES 107 – 116 ). Microtrichia uniformly distributed over most of wing, basal third with some cells with clear areas. Costal bulge absent. Vein R4+5 not fused basally to vein R3. Legs. Femora black, narrowly orange-brown at apex. Tibiae orange-brown, darker apically, hind tibia orange-brown, dark brown-black on apical two-thirds. Fore and mid metatarsi orangebrown, hind metatarsus brown-black; remainder of tarsal segments brown-black. Fore femur with an anterior bristle and a ventral row of long, weak setae. Mid femur with an anterior bristle at about middle and another at apical third; a posteroventral row of 4 or 5 weak bristles and a ventral row of weak bristles. Hind femur with an anterior bristle at about middle and another at apical third; an ventral row of 4 or 5 short, stout bristles and a posteroventral row of 4 or 5 long, fine bristles. Fore tibia with 2 long posteroventral setae; a short subbasal dorsal seta; a ventral row of 5 or 6 setae. Mid tibia with a stout anterodorsal bristle at about apical fourth and a similar ventral seta at about apical third; and an anteroventral row of 4 or 5 long fine, setae. Hind tibiae with a subapical, posterodorsal bristle and another longer anterior one at apical third; a posterodorsal bristle at about middle; a row of 4 anteroventral bristles and a posteroventral row of 5 or 6 long fine bristles. Abdomen. Mostly brownish tomentose, tergite 1 entirely and tergites 2–8 grey tomentose on lateral margins; posterior margins of tergites 2–8 white tomentose. Ground colour of tergites 5–8 noticeably more brownish orange than tergites 1–4. Sternite 2 with long, erect setae scattered over most of surface. Sternites 4–8 with subapical bristles on posterior margin. Posterolateral margins of tergites 2–6 with 2 or 3 pale bristles; posterior margin of tergites 2–8 with black bristles, the posterior bristles of tergites 7 and 8 not distinguishable from those on the posterolateral margin. Terminalia ( Figs 101–103 View FIGURES 101 – 106 ). Brown-orange, epandrium with a uniform covering of black setae, pale along posterior margin. Tergite 8 and sternite 8 with stout, black bristles on posterior margin. Epandrium ( Figs 101, 102 View FIGURES 101 – 106 ) very large and concealing the gonocoxite; dorsally with a small, rounded posterior lobe, basally with a ventral extension covering the gonocoxite and extending posteriorly to form a small, blade-like appendage; gonostylus very long, bowed about middle, extending posteriorly beyond cerci; ventral margin with dense short bristles. Hypandrium ( Fig. 103 View FIGURES 101 – 106 ) short, triangular with a broad base and basally fused to gonocoxite; with black setae longest and stoutest distally.

Female. Differs from male as follows: Body length, 5.7–6.4 mm; thoracic length, 1.3–1.5 mm; wing length, 4.0– 4.5 mm. Abdomen. Segment 8 shining brown-orange, tergite 8 becoming black basally. Terminalia ( Figs 104–109 View FIGURES 101 – 106 View FIGURES 107 – 116 ). Tergite 8 ( Fig. 109 View FIGURES 107 – 116 ) about twice as wide as long; posterior margin rounded with a concave medial area; anterior margin slightly concave; posterior margin with 8–10 stout, black bristles. Sternite 8 ( Fig. 108 View FIGURES 107 – 116 ) about as long as wide and with a small, medial carina on posterior margin; with a posterolateral indentation bearing a stout, black bristle; a subcircular pale area laterally near middle of length. Tergite 9+10 ( Fig. 106 View FIGURES 101 – 106 ), if present, reduced to 2 small sclerites proximally to anterior margin of hypoproct. Genital fork ( Fig. 107 View FIGURES 107 – 116 ) lateral arms narrow and with narrow anterior apodeme. Cerci ( Figs 104–105 View FIGURES 101 – 106 ) ovoid and about as long as hypoproct. Hypoproct ( Fig. 106 View FIGURES 101 – 106 ) fused and with an anterior cleft and a rounded indent on posterior margin; setae on ventral surface with large basal sockets.

Etymology. From rad (L), in radium, and amnis (L), ‘stream of water’, after the type locality. Distribution ( Fig. 4 View FIGURES 4 – 9 ). Known only from the type locality in Kakadu National Park, NT.