Ommatius imaginis, Daniels, Greg, 2017

Daniels, Greg, 2017, Australian species of Ommatius Wiedemann (Diptera: Asilidae) with an anepimeral bristle, Zootaxa 4231 (4), pp. 535-563 : 546-549

Ommatius imaginis sp. nov.

( Figs 8 , 44–59 , 112 )

Diagnosis. This species is very similar in appearance to O. musselbrookensis sp. nov. and the two species are sympatric in the north western part of the distribution of O. imaginis sp. nov. Males can be easily distinguished on features of the terminalia. Females can be distinguished by the shape of sternite 8 and the position of bristle on the distal margin. The extent of the yellow-brown area of the hind tibia can also aid in separating females.

Type material. HOLOTYPE ♂, AUSTRALIA. Queensland . 1 ♂, Murrays Spring , 7 km W Musselbrook Resource Centre Lawn Hill Nat. Pk, 200 m 1835’15” S 13804 ’28”E 10.iv.1995 G. Daniels M.A. Schneider (QM Reg. No. T 207014). PARATYPES. Queensland . 1 ♂, 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) ; 1 ♂, same data as holotype except 13.iv.1995 (QM) ; 1 ♀, same data as holotype except 21.iv.1995 mv lamp (QM) ; 3 ♂, 1 ♀, Ridgepole Waterhole, 24 km ESE of Musselbrook Resource Centre, Lawn Hill Nat. Pk , 1840’15” S 13822 ’15”E 2–9.iv.1995 180 m G. Daniels M.A. Schneider (QM).

Non-type material examined. 1 ♂, 1 ♀, 2053’SX13927’ E Sybella Creek , 400m 17 –22.iii.2001 malaise D.C. Darling, 50584 (QM); 8 ♂, 3 ♀, 22.969°S x 146.379°E Cudmore NP (CM3M) 351m. 28.x.2010 – 2.viii.2011 Lambkin, Starick & Bailey. Melaleuca heath nr drying creek. Malaise. 18517 T224535–7 (QM).

Description. Male. Body length, 5.9–7.9 mm; thoracic length, 1.5–1.9 mm; wing length, 4.4–5.5 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 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 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, lateral pleural sclerites with fine grey tomentum; mesonotum with brownish tomentum, becoming silver-grey laterally; postpronotal lobe with a shining black area posteriorly. 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. Katatergite with a vertical row of long, pale yellowish bristles, which are aligned with a similar row on the metanepisternum. Wing ( Fig. 112 ). With microtrichia uniformly distributed over most of wing, basal half with clear areas in some cells. 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 nearer to the middle. Fore and mid basitarsi yellow-brown, hind basitarsus brown-black, yellow-brown basally; remaining tarsal segments brown-black. Fore femur without stout bristles, a short, black anterior bristle sometimes present near middle of femur; ventrally with a row of 5 or 6 long, weak, pale coloured bristles. Mid femur with 2 anterior bristles, one about mid-point, the other about apical fourth; a downwardly directed anteroventral bristle at about middle of femur and several long fine pale ventral bristles. Hind femur with a black subapical dorsal bristle, a pale anterior bristle at about midpoint, an anteroventral row of 5–7 short, stout bristles which are about as long as thickness of femur and a posteroventral row of 5 or 6 long, weak, pale coloured bristles which are about as long as thickness of femur. Fore tibia posteroventrally with 2 long, weak, pale coloured bristles equally spaced along tibia; 2 long, dark ventral bristles between posteroventral bristles; several stouter and shorter bristles around apex. Mid tibia with a long black anteroventral bristle at about basal third; a similar dorsal bristle at about apical third; ventrally with 2 long, weak, pale coloured bristles equally spaced along tibia and a shorter, stouter, black bristle at apical fourth. Hind tibia with 2 pale anteroventral bristles at about middle and apical fourth; a black, anteriorly directed anterodorsal bristle at apical third; an anteriorly directed dorsal bristle at apical fourth and subbasally. Abdomen. Greyish tomentose, segments 2–5 with a brownish central tomentose area which increases in size with each successive tergite, eventually covering most of tergite; segments 2–8 pale tomentose on posterior margin; and usually with 2 pale posterolateral submarginal bristles. Sternites with pale, semi-erect setae; distal margin of sternite 7 with 2–6 of long bristles. Terminalia ( Figs 44–46 , 54–60 ). Orange-brown, contrasting with tergites. Tergite 8 ( Fig. 60 ) greyish tomentose; laterally about half as wide as tergite 7, deeply emarginate anterior margin, medially less than half the lateral length, pale brownish with about 8 long, stout, black bristles along distal margin. Sternite 8 ( Fig. 59 ) greyish tomentose; broad and narrow, posterior margin about four times length; anterior margin about half as wide as posterior margin; posterior margin with several long black bristles. Cerci ( Figs 44, 45 ) protruding well beyond epandrium. Epandrium ( Fig. 44 , 57, 58 ) rounded distally and covered with short, black setae; with a narrow, posteriorly directed ventral prong which bears a fine seta near its apex; ventrally with an inner dorsal lobe bearing a strongly hooked thumb-like surstylus ( Figs. 57, 58 ), its distal lobe corrugate ventrally. Subepandrial sclerite ( Fig. 55 ) strongly sclerotized on lateral margins, extending from about middle of epandrium to about middle of hypoproct. Hypandrium and gonocoxite ( Figs 44, 46 , 56 ) basally fused, with short, black setae; subequal in length; hypandrium narrow, apically with 4–6 long, black bristles. Gonostylus ( Fig. 56 ) long and narrow, a swollen area mid-length bearing numerous, stout black setae. Aedeagal complex ( Fig. 54 ) with subapically bowed distiphallus; basiphallus disto-ventrally with a carinate process; ejaculatory apodeme about as long as ventral aedeagal apodeme.

Female. Differs from male as follows: Body length, 6.6–9.0 mm; thoracic length, 1.7–2.3 mm; wing length, 5.0– 6.5 mm. Abdomen. Sternite 7 with a row of 4–6 long stout bristles on distal margin. Terminalia ( Figs 47–49 ). Tergite 8 ( Figs 48 , 53 ) with 6–10 long, black, stout bristles along somewhat rounded posterior margin. Sternite 8 ( Figs 49 , 52 ) slightly longer than broad and with a small, apical, medial carina; posterolaterally with a weakly, raised lobe bearing a stout, black bristle. Tergite 9+10 ( Figs 48–50 ) heavily sclerotized, narrow dorsally, widening slightly laterally then becoming narrower again. Hypoproct ( Figs 47, 49 , 50 ) long and fused for most of its length, deeply emarginate anteriorly, less so posteriorly. Genital fork ( Fig. 51 ) anteriorly with long apodeme and deeply emarginate between the bases of the arms.

Etymology. Derived from the Latin, imaginis , ‘likeness’, referring to the similarity between this species and O. musselbrookensis sp. nov.

Distribution ( Fig. 8 ). North-western to central-eastern Qld. The distribution is sympatric with O. musselbrookensis sp. nov. in the northern part of the range of O. imaginis sp. nov.

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 44 – 49. Ommatius imaginis sp. nov. (44 – 46). Male terminalia. (44). Lateral view; (45). Dorsal view; (46). Ventral view. (47 – 49) Female terminalia. (47). Lateral view; (48). Dorsal view; (49). Ventral view. Abbreviations: st, sternite; tg, tergite. Scale bar, 0.25 mm.

FIGURES 50 – 60. Ommatius imaginis sp. nov. (50 – 53). Female terminalia. (50). Tergite 9 + 10 and cerci; (51). Genital fork; (52). Sternite 8; (53). Tergite 8. (54 – 60). Male terminalia. (54). Aedeagal complex; (55). Subepandrial sclerite, ventral view; (56). Hypandrium, gonocoxite and gonostylus; (57). Epandrium, subepandrial sclerite and cerci, ventral view; (58). Enlargement of fig. 57 showing epandrial surstylus; (59). Sternite 8; (60). Tergite 8. Abbreviations: dist, distiphallus; ejap, ejaculatory apodeme; 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.