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

Ommatius radamnis sp. nov.

( Figs 4 , 101–109, 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 . 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 ). 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 ). 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 ) 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 ) 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 ). Tergite 8 ( Fig. 109 ) 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 ) 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 ), if present, reduced to 2 small sclerites proximally to anterior margin of hypoproct. Genital fork ( Fig. 107 ) lateral arms narrow and with narrow anterior apodeme. Cerci ( Figs 104–105 ) ovoid and about as long as hypoproct. Hypoproct ( Fig. 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 ). Known only from the type locality in Kakadu National Park, NT.

Figures

FIGURES 4 – 9. Distribution of Ommatius spp. with anepimeral bristle. (4). O. radamnis sp. nov. (red circle) and O. aquilonaris sp. nov. (green circle); (5). O. musselbrookensis sp. nov.; (6). O. melasmus sp. nov.; (7). O. burwelli sp. nov.; (8). O. imaginis sp. nov.; (9). O. limbatus sp. nov.

FIGURES 101 – 106. Ommatius radamnis sp. nov. (101 – 103). Male terminalia. (101). Lateral view; (102). Dorsal view; (103). Ventral view. (104 – 106). Female terminalia. (104). Lateral view; (105). Dorsal view; (106). Ventral view. Abbreviations: tg, tergite. Scale bar, 0.25 mm.

FIGURES 107 – 116. (107 – 109). Terminalia of Ommatius radamnis sp. nov. (107). Genital fork; (108). Sternite 8; (109). Tergite 8. (110 – 116). Right wing of male Ommatius spp. (110). O. aquilonaris sp. nov.; (111). O. burwelli sp. nov.; (112). O. imaginis sp. nov.; (113). O. limbatus sp. nov.; (114). O. melasmus sp. nov.; (115). O. musselbrookensis sp. nov.; (116). Ommatius radamnis sp. nov. (female). (110). Scale bar, 1.00 mm and as indicated.