Ceratomerus attenuatus, 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 : 16-18

Ceratomerus attenuatus n.sp.

Figs. 16, 35–38, 43

Type material. HOLOTYPE 3, “ AUST [ralia]: NSW[New South Wales]: Dorrigo NP/ Wonga Walk, 700 m / Crystal Shower Falls / 2.iv.1995 / B.J. Sinclair ”; “ HOLOTYPE / Ceratomerus / attenuatus / Sinclair [red label]” AMS K175242 . PARATYPES: Australian Capital Territory: 433, 1♀, Blundells Ck, 35°22'S 148°50'E, iii., vi.1987, v.1988, DHC ( ANIC) . New South Wales: 3, same data as holotype ( AMS); 433 , 3♀♀, Border Ranges NP, Brindle Ck, 1000 m, rainfor., y.pans, 25–26.i.1995, BJS ( CNC, ZFMK) ; 13, Dorrigo NP, Rosewood Ck , 23.i.1995, BJS ; 533, 4♀♀, Gloucester Tops, 1280 m, Nothofagus, MT , 19.xi–4.xii.1988, DJB ; 1 ♀, Styx River SF, George’s Ck For. Res., Cunnawarra Ck , 31.iii.1995, BJS ( AMS) ; 13, 2♀♀, nr Gloucester Tops, 1290 m, Nothofagus , 14– 19.xi.1988, DJB ( AMS, ANIC) ; 1♀, Monga SF, 19–24.i.1984, L. Masner ( CNC) . Queensland: ♀, Lamington NP, Green Mtns, Elabana Falls, Canungra Ck , 6.v.1994, BJS ( AMS) . Victoria: 933, 1♀, Acheron Ck, 29 km from Warburton ; y.pans, rainfor. ck, 400 m, 1–3.xii.1994, DJB ; 533, Burrowa-Pine Mtn NP, Bluff Ck Falls , 400 m, riverine for., y.pans, 29.xi.1994, DJB ; 233, 1♀, same locality, swept over pools, 29.xi.1994, DJB ; 13, Cement Ck, rainfor., 800 m, y.pans, 1–3.xii.1994, DJB ; 6 33, 3♀♀, Errinundra Plateau; Bonang Ck , y.pan, 1.iv.1990, DJB ; 233, 4♀♀, same locality, Result Ck ; 13 , 1♀, Errinundra Plat., Result Ck + Gap Rd. , 900 m, cool rainfor., y.pans, 6.xii.1994, DJB ( AMS) ; 533, 1♀, same locality, Cudgewa Bluff Falls , 400 m, rainfor., 30.xi.1994, BJS ( CNC, ZFMK) .

Diagnosis. Recognized by the very slight inflexion of R 2+3 around the stigma, dorsolateral margin of female sternite 7 concave with posterior corner extended dorsally, and distinctive capsule-like male hypopygium with long slender cerci.

Description. Wing length 2.8–3.5 mm.

Male. Head dark brown, dull; upper half of face pale brown, lacking setae; lower half of face with dense white pruinescence; ocellar triangle with 2 widely spaced, long, divergent bristles, inserted anterior to lateral ocelli; postocellar bristles short, one-half length of ocellar bristles; 3 pairs of vertical bristles, shorter than ocellar bristles; postocular bristles short, slender, overlapping less than onethird of eye. Antenna with length of scape slightly more than half height of eye, with 2 dorsal setae, several lateral setulae and 1 long ventral seta; pedicel globular, with setae confined to apical fringe. Postpedicel covered by long, dense pruinescence, length slightly longer than height of head; base rectangular; apical half strongly tapered, subequal in length to base; three-segmented stylus subequal in length to postpedicel; segment 8 long, 4–5× longer than width; stylus concolorous with remaining segments. Base of labrum lacking dorsal process; palpus brown, slender, onefourth length of labrum, with several dark setae; prementum with short setae only.

Thorax. Scutum and postnotum dark brown; pleura brown; postpronotal lobe pale; pale streak extending ventrally along proepisternum and anterior margin of anepimeron; scutum lacking vitta of pruinescence. Alternating row of short acrostichals to prescutellar depression, directed anteriorly; 4 dc, fourth dc short and slender; 1 pprn; 1 presut spal; 1 npl; 2 psut spal; 1 pal, short; 2 sctl; additional setulae lacking. Antepronotum with pair of long setae.

Wing ( Fig. 16) infuscate, stigma distinct, short somewhat triangular in shape at apex of cell r 1; 1 long costal seta; costal margin with unmodified setulae; posterior margin lacking incision; posterior setal margin complete, with 3 long setae on wing stem. R 1 reaching costa before middle of wing; R 2+3 running parallel and close to costa, slightly arched around stigma; medial fork proximal to radial fork; cell dm rectangular, slender; auxiliary crossvein between R 2+3 and R 4 lacking. Halter with dark knob.

Legs. Fore and mid coxae yellow, hind coxa yellowishbrown; base of femora, especially inner margin yellow, becoming dark brown towards tip. Fore coxa slightly less than twice length of mid coxa, lacking modified setae. Fore trochanter lacking modified setae. Fore femur slightly swollen, with av row of fine setae, decreasing in length apically; 1 preapical dorsal seta. Fore tibia slightly shorter than femur; apex with anteroapical comb, not dilated. First tarsomere nearly two-thirds length of fore tibia, lacking modified setae; all tarsomeres slender.

Mid coxa lacking modified seta. Mid femur partially swollen, with pv row of short, dark setae along middle twothirds; base with long erect pv seta; basal third with av biserial row of short dark setae ( Fig. 38). Mid tibia not swollen at mid-length, with av row of short setae; pv surface with row of slender setae, shorter than width of tibia; 1 dorsal seta on basal third and 1 pd seta near mid-length. First tarsomere subequal in length to remaining 4 tarsomeres, with many erect pv setae, including long basal seta; tarsomere 5 not noticeably more flattened than on other legs.

Hind coxa with unmodified setae. Hind femur straight with 1 preapical ad seta; ventral surface lacking distinct row of setae beneath. Hind tibia straight, shorter than femur, apex partially dilated, bearing posteroapical comb; pv surface lacking setae; 3 erect ad setae on apical two-thirds; dorsal margin with 2 erect setae on distal half. Hind tarsomeres longer than tibia; first tarsomere with 1 long, erect ventral seta near base.

Abdomen brown, concolorous with thorax, sclerites of segment 1–6 well sclerotized; posteromarginal setae increasing in length apically, longest on T6, where setae half width of abdomen; sternites and tergites lacking modified setae and ridges; T7 thinly sclerotized medially, lacking long posteromarginal setae; S7 only slightly longer than preceding sternite, anterolateral margin produced anteriorly; T8 bow-tie shaped.

Terminalia ( Figs. 34, 35). Hypandrium convex, posterior margin produced into pair of long processes, expanded apically, nearly subequal in length to postgonites; gonocoxal apodemes developed, not projected beyond anterior margin; postgonites upright, gently arched posteriorly, fused anteriorly with pair of lateral processes (phallic), and concave median process; phallus upright, gently arched with subapical hook and arched apex. Epandrial lamella nearly circular in lateral view, forming a partial capsule fused ventrally to hypandrium; bearing short, oblique, finger-like, posterior epandrial lobe. Surstylus short, thumb-like; inner margin with dense mat of short, stout setae; lateral margin with row of setae. Subepandrial plate narrow, extending laterally to epandrial margin; apex bearing slender process projected beyond epandrium; base of process secondarily fused to epandrium. Cercus very long and slender, sparsely clothed in setae.

Etymology. The specific name is from the Latin attenuatus (drawn out or thin), referring to slender, thread-like male cercus. Female. Similar to male except as follows: av row of setae of fore and hind femora short; mid femur slender; lacking rows of ventral setae on mid femur and tibia; mid tibia with long, erect, ad and pv apical seta; erect pv seta at mid-length. Apical segments retracted into segment 7; apical margins of segment 7 not folded inwards; posterior margin of T7 entire, with fringe of golden setulae; lateral margin of S7 concave, with pd corner extended sharply dorsally. Terminalia ( Fig. 37): median region of T8 with deep Ushaped weakly sclerotized zone; fringe of long setae anterior to membranous region; anterior margin with flattened, internal, median plate. S8 triangular in lateral view, with short, rounded process; posterior margin invaginated, forming internal plate. T10 split medially into pair of rectangular sclerites, bearing double row of spine-like setae along posterior margin. Cercus bearing biserial row of spinelike setae, with short, slender marginal setae. Spermathecal receptacle oval, flattened with duct attached to broad asymmetrical neck ( Fig. 36).

Distribution. This species is recorded sporadically from streams in subtropical rainforests of northern NSW and southern Queensland to gallery rainforests of Victoria ( Fig. 43).