Ceratomerus victoriae, 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 : 14-16

Ceratomerus victoriae n.sp.

Figs. 7, 8, 14, 15, 25–28, 30–33

Type material. HOLOTYPE 3, “ AUST: VIC[toria]: 9 km N/ Warburton, Cement Ck./ 1–3.xii.1994 / B.J. Sinclair / ex. Nothofagus for.”; “ HOLOTYPE / Ceratomerus / victoriae / Sinclair [red label]” AMS K175241 . PARATYPES: Victoria: 1533, 10♀♀, same data as holotype ( AMS, ANIC, CNC, ZFMK); 233 , 3♀♀, Acheron Ck, 29 km from Warburton, 1–3.xii.1994, y.pans, BJS, DJB ; 4 33, Cement Ck, 800 m, rainfor., y.pans, 1–3.xii.1994, DJB ; 2 ♀♀, Errinundra Plateau, Result Ck, & Gap Rd, 920 m, rainfor., y.pans, 6.xii.1994, DJB ; 13, 3♀♀, Otway Ra., SE Beech For., Beauchamp Falls , y.pans, 350 m, 4–5.xii.1994, DJB

( AMS); 1♀, Acheron Gap , 15 km NNE Warburton, MT , 830 m, 6– 12.xii.1990, D. Pollock, L. Reichert; 13, Cement Ck , 27.x.1961, DHC ; 1♀, Cement Ck , 670 m, N. cunninghamii , 10–17.i.1980, A. Newton, M. Thayer ( ANIC); 13, Cement Ck, 27.iii.1972, A. Neboiss ( MVM); 433 , 2♀♀, Errinundra Plateau , Gap Rd, Result Ck Falls, 6–7.xii.1994, BJS ( MVM, ZFMK) ; 333, 2♀♀, Otway Ra., Beauchamp Falls , Nothofagus , 3.xii.1994, BJS ( ZFMK) ; 233, 4♀♀, Otway Ra. , Melba Gully SP, temperate rainfor., ck, 4.xii.1994, BJS ( CNC) .

Diagnosis. Males are readily recognized by highly modified midlegs and anal lobe of the wing acutely produced, bearing many stout setae. Females are separated by the yellowcoloured pleura, short base of the medial fork, and darktipped stylus.

Description. Wing length 4.2–4.5 mm, similar to C. athertonius except as follows:

Male. Head. Postocellar bristles one-third length of ocellar bristles; vertical bristles somewhat shorter than ocellar bristles; postocular bristles short, slender, overlapping one-third of eye. Antenna long, with scape slightly longer than height of eye ( Fig. 25). Postpedicel 1.6× longer than scape; palpus yellow, short and slender, one-fourth length of proboscis, with several long, dark setae; prementum with 1 pair of erect setae.

Thorax. Mesonotum and postnotum dark, lacking dorsal stripes; postpronotal lobe brown, pleura yellow. Acrostichals in alternating single row of short setulae to prescutellar depression, directed anteriorly; 4 dc, posterior dc short and slender; 2 psut spal, lower near wing base; numerous setulae scattered on scutum, particularly around presut spal and dc.

Wing ( Fig. 14). Anal lobe acutely produced, bearing more than 15 short, stout setae; posterior margin lacking incision, with 3 stout, flattened setae on wing stem. C with 12 widely spaced, long dorsal setae on upper surface between tip of Sc and R 1, longer than costal seta. Cell dm oval; medial fork proximal to radial fork by more than length of R 4, usually with very short petiole or stem. Halter with dark knob.

Legs. Coxae concolorous with pleura, hind coxa somewhat darker; base and inner margin of femora yellowish brown, dark apically; remaining leg segments dark. Inner margin of fore coxa gradually tapered, parallelsided, with anterior row of long setae on apical half and inner subapical patch of fine setae; apical third with long stout seta, half length of coxa on near inner ventral margin. Fore trochanter unmodified. Fore femur swollen, inner margin concave on basal two-thirds; upper edge of depression with row of 7 long, ventrally directed setae, longer than width of femur ( Fig. 26); av margin with row of stout, black setae, decreasing in length apically, longest on apex of ventral swelling; apical fourth with ventral swelling with av fringe of long setae and 1 ventral, near horizontal projecting stout seta. Fore tibia longer than femur + trochanter, with mid-length constriction or weakening; distal half with anterior and posterior surfaces concave, clothed in short appressed setae; apex with pd comb of tightly appressed, arched, stout setae; anteroapical comb present. First tarsomere less than half length of fore tibia, with deep basal notch; short, arched comb opposing tibial comb ( Fig. 27); 1 erect, ventral seta at base; distal 4 tarsomeres nearly twice length of first tarsomere.

Mid coxa with slender setae. Mid femur thickened, strongly arched, with large curved, ventral tubercle; tubercle lined with long ventral setae, terminating in pointed, subapical finger-like process; basal third with long av and pv setae, longer than width of femur; apical fourth with short, slender, black pv appendage ( Figs. 7, 8). 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; av margin with several short, rounded lobes; 2 long, erect ad setae. First tarsomere 1.3× longer than tibia; base with pv row of 3 stout setae; apical half with anterior row of stout, curved, flattened setae; basal half with long, anterior and ad setae, longer than width of tibia; first tarsomere nearly subequal in length to remaining 4 tarsomeres.

Hind femur less than twice length of fore femur, bearing av patch of curled, golden setulae; basal third with row of 3–5 long, erect setae; 1 erect, subapical dorsal seta. Hind tibia longer than femur, apex not dilated, bearing posteroapical comb; 4 erect ad setae and 2 erect dorsal setae on apical half. Fifth tarsomere not strongly flattened.

Abdomen. Tergites concolorous with thorax, with long, stout setae along posterior margin of T1–6; sternites pale brown; T8 very slender, one-sixth length of sternite, lateral margin expanded.

Terminalia ( Figs. 30, 31). Hypandrium with posterior broad flap, folded anteriorly, bearing crown of long setae; paired articulated postgonites flanking phallus, projecting dorsally, apex forked. Phallus flattened, apex truncate with lateroapical sickle-shaped extensions curving around anterior margin of postgonites. Epandrium with 1 very long, stout seta on ventrolateral margin; pair of round setose lobes flanking surstylus, with anterior lobe bearing radiating crown of thickened setae, posterior lobe bearing crown of very stout, flattened setae. Bacilliform sclerite broad, fused to epandrium near base of cercus; small, round lobe from bacilliform sclerite near anterior epandrial lobe. Surstylus fin-shaped, tapered, bearing lateral setulae; base with pair of 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; palpus dark. Medial fork with very short petiole, basal to radial fork by more than length of R 4 ( Fig. 15). Apex of fore tibia slightly expanded. Mid tibia with long, erect ventroapical seta; 1 erect ventral seta at mid-length; basal third with ad and pd seta. Posterior margin of T7 with complete fringe of golden setulae. Terminalia ( Fig. 32): S8 subtriangular in lateral view. Spermathecal receptacle oval, flattened, with distinct wide neck ( Fig. 33).

Distribution. This species is known from several isolated remnant patches of Nothofagus rainforest in Victoria ( Fig. 28). These localities are often in deep, cool ravines, well shaded and consequently the stream temperatures are also fairly cool.

Biology. Relatively large numbers were swept above Cement Creek from the overhanging frons of tree ferns. Adults were also aspirated from the under side of emergent rocks that had formed small, dark enclaves above the water surface. Adults appeared to seek these hiding spots, which was identical to behaviour observed for C. barringtonensis .

Etymology. Refers to the state where the material for this species was collected.