Australian species of Ommatius Wiedemann (Diptera: Asilidae) with an anepimeral bristle Author Daniels, Greg text Zootaxa 2017 4231 4 535 563 journal article 36558 10.11646/zootaxa.4231.4.3 6313e443-10b8-496d-af28-ffbdfea0360d 1175-5326 292658 C724F2C5-C2CD-47BB-BEFA-2E6B44316BF7 Ommatius musselbrookensis sp. nov. ( Figs 3 , 5 , 85–100 , 115 ) Diagnosis. This species is very similar in appearance to O. imaginis sp. nov. and the two species are sympatric in the north-western part of the distribution of O. musselbrookensis sp. nov. Males can be easily separated on terminalia and females by the shape and bristles on sternite 8. The extent of the yellow-brown area of the hind tibia can also help to separate females. Type material. HOLOTYPE ♂ , AUSTRALIA . Queensland . 1 ♂ , Murrays Spring , 7 km W / Musselbrook Resource Centre / Lawn Hill Nat. Pk, Qld 200 m / 1835’15” S 13804 ’28”E / 21 April 1995 / G. Daniels M.A. Schneider / ( QM Reg. No. T 207016). PARATYPES . Northern Territory . 10 ♂ , 6 ♀ , Border Waterhole , 15 km W of Musselbrook Resource Centre Lawn Hill Nat. Pk, 1836’44” S 13759 ’30”E 19.iv.–6.v.1995 200 m G. Daniels M.A. Schneider (QM). Queensland . 2 ♂ , 1813.9’ Sx 1385.3’ E Elizabeth Ck , Boodjamulla NP 18–22.iv.2005 12398 M. Mathieson , G. Smith. 170 m bloodwood open for, malaise (QM) ; 19 ♂ , 15 ♀ , Murrays Spring , 7 km W Musselbrook Resource Centre Lawn Hill Nat. Pk, 200 m 1835’15” S 13804 ’28”E 21.iv.–14.v.1995 G. Daniels M.A. Schneider (QM) ; 3 ♂ , 2 ♀ , Musselbrook Ck , 11 km ENE Musselbrook Resource Centre Lawn Hill Nat. Pk, 140 m 1836’45” S 13807 ’46”E 8.v.1995 G. Daniels M.A. Schneider (QM) ; 1 ♂ , 6 ♀ , Musselbrook Ck , 19 km NE of Musselbrook Resource Centre Lawn Hill Nat. Pk, 1829’59” S 13817 ’01”E 30.iv.–11.v.1995 130 m G. Daniels M.A. Schneider (QM); 1 ♂ , 8 ♀ , Holts Ck , 8 km NE Musselbrook Resource Centre Lawn Hill Nat. Pk, 1832’32” S 13811 ’06”E 10–14.v.1995 150 m G. Daniels M.A. Schneider (QM) ; 1 ♀ , Stockyard Ck , 18 km NE of Musselbrook Resource Centre Lawn Hill Nat. Pk, 1826’44” S 13828 ’35”E 16.v.1995 120 m G. Daniels M.A. Schneider (QM) ; 1 ♂ , 2 ♀ , Amphitheatre waterhole area 27 km N Musselbrook Resource Centre , Lawn Hill Nat. Pk , 1821’08” S 13809 ’43”E 3–13.v.1995 200 m G. Daniels M.A. Schneider (QM) ; 1 ♀ , Amphitheatre spring area 28 km N Musselbrook Resource Centre , Lawn Hill Nat. Pk , 1820’58” S 13811 ’09”E 4.v.1995 200 m G. Daniels M.A. Schneider (QM). Description. Male. Body length, 7.0– 7.6 mm ; thoracic length, 1.7–2.0 mm; wing length, 5.0– 5.6 mm . Head. Face gently rounded, barely 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 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. Beard with branched hairs. Flagellum about half as long as pedicel and subspherical or conical. Style with setae in two ranks. Thorax. Ground colour black, mesonotum with brownish tomentum, becoming silver-grey laterally; postpronotal lobe with a shining black anterior area; lateral pleural sclerites with fine grey tomentum. Acrostichal setae seemingly absent but visible when viewed in profile. Postpronotal lobe with a few long weak, whitish setae. 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. 115 ). Microtrichia uniformly distributed over most of wing, basal half with some cells with clear areas. Costal bulge absent. Vein R4+5 not fused basally to vein R3. Vein M1 sub-parallel with vein R5. Legs. Femora black, narrowly orange-brown at apex. Fore and mid tibiae yellow-brown, brown-black apically; hind tibia yellowbrown, gradually becoming brown-black from about apical third, except ventrally where the darkening begins almost at base. Fore and mid metatarsi yellow-brown, 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 a black subapical dorsal bristle, with a pale anterior bristle at about middle; an anteroventral row of 5–7 short, stout bristles which are about as long as thickness of femur and a posteroventral row of 7 or 8 long bristles which are at least 50% longer than thickness of femur. Fore tibia with 2 long posteroventral setae; a short subbasal dorsal seta; a ventral row of 6 or 7 setae. Mid tibia with a stout anterodorsal bristle at about apical fourth and a similar ventral seta at about apical third. Hind tibiae with a subapical, anterodorsal bristle and another longer one at apical third; a posterodorsal bristle at about middle; 2 anteroventral bristles, one near the middle the other at apical fourth. Abdomen. Mostly brownish tomentose, segment one entirely and segment 2 basally grey tomentose; segments 2–7 with pale tomentum on posterior margin; tergites 2–7 with pale posterolateral submarginal setae, becoming more obvious on each successive segment until extending around entire posterior margin; sternites with pale, semi-erect setae; apical margin of sternites 5–8 black setose. Terminalia ( Figs 85–87 , 95–100 ). Orange-brown, epandrium sometimes deep brown and contrasting with tergites. Tergite 8 pale brownish and narrow, about one-third as wide as segment 7; broad and narrow, posterior margin about four times length and anterior margin about half as wide as posterior margin; posterior margin with several long black bristles. Sternite 8 ( Fig. 98 ) with posterior margin about twice as wide as long and with about eight long, stout, black bristles along posterior margin; anterior margin concave. Epandrium ( Figs 85, 87 , 97 ) ovoid, not fused, with a small dorsal apical lobe and a ventral, posteroventrally directed, semi-transparent, blade-like lobe; posterior margin with a C-shaped process on inner margin. Gonocoxite ( Fig. 96 ) with a dorsal apodeme at about basal third; gonostylus long, vertical, with long setae at about middle. Hypandrium ( Fig. 96 ) extending beyond gonocoxite, forming an apical knob from which arises a fan of about 4 long black bristles. Aedeagal complex ( Fig. 95 ) with a short, dorsal distiphallus; basiphallus disto-ventrally with several ventral lobes; ejaculatory apodeme about as long as ventral aedeagal apodemes, which arise above mid-point of basiphallus. Subepandrial sclerite ( Figs 99, 100 ) complex, ventrally with anterior and posterior lobes; anterior lobes rugose. Female. Differs from male as follows: Body length, 7.0–9.0 mm; thoracic length, 1.6–2.2 mm ; wing length, 5.0– 6.5 mm . Abdomen. Sternites 2–6 with 2–6 erect subbasal bristles. Terminalia ( Figs 88–94 ). Sternite 8 ( Fig. 93 ) a little wider than long; distal margin with a small medial indentation and a larger submedial emargination bearing a long black bristle which arises near its base. Tergite 8 ( Fig. 94 ) a little wider than long; posterior margin concave and with several long, stout bristles. Tergite 9+10 and cerci not retracted into segment 8. Tergite 9+10 ( Fig. 91 ) thread-like dorsally, abruptly widening laterally before abruptly becoming thread-like again. Hypoproct ( Fig. 90 ) as long as cerci and fused for most of length and with a posterior medial notch and a longer, narrower anterior notch. Genital fork ( Fig. 92 ) proximally with long apodeme and deeply emarginate between the bases of the arms, broadest mid-length. FIGURES 85–90. Ommatius musselbrookensis sp. nov. (85–87) Male terminalia. (85). Lateral view; (86). Dorsal view; (87). Ventral view. (88–90) Female terminalia. (88). Lateral view; (89). Dorsal view; (90). Ventral view. Abbreviations: st, sternite; tg, tergite. Scale bar, 0.25 mm. FIGURES 91–100. Ommatius musselbrookensis sp. nov. (91–94). Female. (91). Tergite 9+10, cerci; (92). Genital fork; (93). Sternite 8; (94) Tergite 8. (95–100). Male. (95). Aedeagal complex; (96). Gonocoxite, gonostylus, hypandrium. (97). Epandrium (ventral view), subepandrial sclerite removed; (98). Sternite 8; (99). Subepandrial sclerite, lateral view; (100). Subepandrial sclerite, ventral view; Abbreviations: aedap, aedeagal apodeme; st, sternite; tg, tergite. Scale bar, 0.25 mm and as indicated. Etymology. The specific name is derived from the type locality. Distribution ( Fig. 5 ). Sympatric with O. imaginis sp. nov. Most specimens are known from west of Lawn Hill National Park in north-western Qld. A few specimens have been collected in the same general area but less than 1 km across the border in the NT.