Ceratomerus barringtonensis, Bradley J Sinclair, 2003

Bradley J Sinclair, 2003, Taxonomy, Phylogeny and Zoogeography of the Subfamily Ceratomerinae of Australia (Diptera: Empidoidea), Records of the Australian Museum 55, pp. 1-44 : 10-12

Ceratomerus barringtonensis n.sp.

Figs. 3, 4, 12, 19–21, 28

Type material. HOLOTYPE 3, “ AUST:NSW[New South Wales]: Barrington / Tops NP, Williams R./ 21.i. 1995, 480 m/ rainfor.,BJ Sinclair”;“ HOLOTYPE / Ceratomerus / barringtonensis / Sinclair [red label]” AMS K175240 .

PARATYPES: New South Wales: 333, 1♀, same data as holotype ( AMS, ZFMK); 433, same locality as holotype, 19.xii.1993 ( CNC, ZFMK) ; 1♀, Gloucester Tops, Nothofagus, 1280 m , MT , 4–30.xii.1988, DJB ( AMS) .

Diagnosis. Males are readily recognized by the greatly swollen mid femur and truncate anal lobe of the wing, bearing long, wavy, slender setae. Females are distinguished by the long stigma, short base of the medial fork, yellow-coloured pleura, with brown smudges and dark-tipped stylus.

Description. Wing length 3.5–3.8 mm, similar to C. athertonius except as follows:

Male. Head. Postocellar bristles one-third length of ocellar bristles; postocular bristles short, slender, overlapping less than one-third of eye. Antenna long, with scape slightly longer than height of eye; scape with many dorsal setulae; three-segmented stylus one-half length of postpedicel; segment 8 not longer than wide; apical two-thirds of stylus dark. Palpus brown, short and slender, with several long, dark setae; prementum with 2 pairs of long, erect setae.

Thorax. Mesonotum and postnotum dark, lacking dorsal stripes; postpronotal lobe yellowish-brown, pleura yellow with brown smudges on lower margins of sclerites. Acrostichals in alternating single row of short setulae to prescutellar depression, posterior half directed anteriorly; 4 dc, posterior dc short and slender; lower psut spal near wing base.

Wing ( Fig. 12). Anal lobe truncate, bearing pair of long, stout setae, and 6–12 pairs of long, wavy lateral setae longer than costal seta; posterior margin lacking incision, with 5– 6 stout setae on wing stem. C with 16 closely spaced, long dorsal setae on upper surface between tip of Sc and R 1, shorter than costal seta. Cell dm oval; medial fork with petiole lacking or very short, proximal to radial fork by more than length of R 4. Halter with dark knob.

Legs. Coxae concolorous with pleura, hind coxae somewhat darker; ventral margin of femora yellowish brown, upper surface light brown; remaining leg segments dark. Inner margin of fore coxa concave, with anterior row of long setae near mid-length; basal third with transverse band of fine, wavy setae. Fore trochanter unmodified. Fore femur somewhat inflated, slightly sinuous, inner margin flat lacking setae; posterior margin with single row of short setae along entire length; 1 long stout seta at base, length twice width of femur; av row of setae sinuous, apically increasing in length to greater than width of femur; basal third with biserial row of pv setae, outer row longer than width of femur; 1 long, erect preapical dorsal seta; apical fourth with ad patch of long setae. Fore tibia shorter than femur, cylindrical, with partial subapical constriction; basal half with long av and ad setae, longer than width of tibia; distal third with short, dense setae; anteroapical comb on apex of anteriorly deflected tip. First tarsomere three-quarters length of fore tibia, cylindrical; long ventral setae, longer than width of tarsus; 1 erect ventral seta at base.

Mid coxa with slender setae. Mid femur greatly swollen, strongly arched, with large curved, ventral tubercle; tubercle with 2–3 long ventral setae and 3 stout subapical setae, terminating in round, subapical finger-like process; basal third with short setae; apical fourth with short, tapered, black pv appendage ( Fig. 3). Mid tibia two-thirds length of femur, laterally expanded, with deep concave ventral surface; pv margin with row of long setae, longer than width of tibia; anteroapical margin with broad lobe extending beyond base of tarsomere, lateral margin with row of more than 10 short, curved setae; av margin of basal half with several short, convoluted lobes, pair of erect, stout setae, and comb of short setae; 1 long, erect pd apical seta ( Fig. 4). First tarsomere sinuous, nearly twice length of tibia; subbasal lobe densely clothed in microtrichia; anterior and posterior margins with long, curved setae, longer than twice width of tarsus, longest at mid-length; first tarsomere shorter than remaining 4 tarsomeres.

Hind femur bow-legged, nearly twice length of fore femur, bearing long av and pd setae on apical third; 1 erect, subapical dorsal seta. Hind tibia with ad and av row of long, erect setae, nearly 3× width of tibia; basal fourth with long, erect dorsal seta. Hind tarsomeres longer than tibia; tarsomeres 1–3 clothed in long erect setae; fifth tarsomere dorsoventrally flattened.

Abdomen. Sclerites paler than thorax, with long, stout setae along posterior margin of T1–6; posterior margin of T7 with broad U-shaped membranous region; T8 very slender, onesixth length of sternite, lateral margin expanded.

Terminalia ( Fig. 19). Hypandrium with posterior broad flap, folded anteriorly, bearing crown of long setae; paired articulated postgonites flanking phallus, project dorsally, apex attenuated. Phallus flattened, apex truncate with lateroapical sickle-shaped extensions curving around anterior margin of postgonites. Epandrium with 1 very long and 3–4 shorter, stout setae on ventrolateral margin; pair of round lobes flanking base of surstylus: anterior lobe with apical setulae, posterior lobe with crown of very stout, flattened setae. Bacilliform sclerite broad, fused to epandrium near base of cercus; small lobe from bacilliform sclerite at base of anterior epandrial lobe. Surstylus finshaped, tapered, bearing lateral setulae; base with 4 long setae. Cercus short, fleshy, apex acute, expanded laterally around anus; posterior surface well sclerotized.

Female. Similar to male and female of C. athertonius except as follows: postpedicel short, subequal in length to scape; wing lacking posterior modification and setae; cell dm rectangular; medial fork with short petiole, basal to radial fork by more than length of R 4. Legs lacking modified appendages and setae; apex of fore tibia slightly expanded. Mid tibia with 1 ventral bristle at mid-length. Hind tibia with 3 ad bristles and 1 dorsal bristle. Terminalia ( Fig. 21): median region of T8 with deep U-shaped weakly sclerotized zone; fringe of long setae. S8 subtriangular in lateral view. Spermathecal receptacle spherical, with short neck; base of spermathecal duct pigmented ( Fig. 20).

Distribution. This species is known only from two localities in Barrington Tops National Park ( Fig. 28).

Biology. Most adult specimens were collected from the underside of somewhat flattened emergent rocks in the Williams River located at Rocky Crossing. This river valley is surrounded by subtropical rainforest. A single specimen was collected at 1280 m in Nothofagus forest.

Etymology. Named in reference to type locality.