Ceratomerus macalpinei, 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 : 23-26

Ceratomerus macalpinei n.sp.

Figs. 69, 71

Type material. HOLOTYPE 3, “[ Aust : NSW]/ Blue Mts. NP, Mt. Wilson, / Waterfall CK, / 12–13.Dec.1998 / YPans, B.J. Sinclair ”; “ HOLOTYPE / Ceratomerus / macalpinei / Sinclair [red label]” AMS K175247 .

PARATYPES: New South Wales: 13, 3♀♀, same data as holotype; 13, same locality, 21.xi.1993 ( CNC, ZFMK); 13 , 1♀, Katoomba , 26.x., 18.xi.1955, G.H. Hardy; 13 , 1♀, Blue Mtns NP, Mt. Wilson , 19.xii.1986, DKM , B.J. Day , R . de Keyzer; 233, Morton NP, nr Milton, Cooyoyo Ck , 500 m, 35°17'S 150°11'E, 6.xi.1997, A. Leask ( AMS) ; 1♀, Mt. Wilson , 19.xi.1921, A. Tonnoir ( ANIC) .

Diagnosis. Recognized by the slight inflexion of R 2+3 around the stigma, broad, yellow pleural band broad extending to katepisternum, heavily sclerotized male tergites 4–6 and anvil-shaped male cercus. This species can be distinguished from C. malleolus by the narrow lobe beneath the cercus, which is roundly expanded apically and tapered posterior tip of the cercus.

Description. Wing length 3.3–3.5 mm, similar to C. attenuatus except as follows:

Male. Head. Postocellar bristles short, one-third length of ocellar bristles. Antenna with length of scape slightly less than height of eye; postpedicel length less than height of head; three-segmented stylus longer than postpedicel; segment 8 elongate, 4× as long as wide. Palpus one-fifth length of labrum.

Thorax. Pale streak extending ventrally from proepisternum across pleura.

Wing as in C. attenuatus .

Legs. Fore and mid coxae and ventral margin of femora yellow, remaining leg segments brown, darker towards tip. Fore femur slightly swollen, with av row of fine setae, decreasing in length apically; basal setae longer than width of femur. First tarsomere greater than half length of fore tibia.

Mid femur more strongly swollen than fore femur, with pv row of short, dark setae; base with long erect pv seta; basal half with av brush of short dark setae, increasing in length medially. Mid tibia with pv row of slender setae, longer than width of tibia; ventroapically with row of short erect setae on apical sixth; 1 ad seta near mid-length.

Hind femur straight with 1 preapical dorsal and 1 av seta; ventral surface with av row of short, fine setulae. Hind tibia with 2 erect ad setae on apical half; dorsal margin with row of 3 long, erect setae. Hind tarsomeres slightly longer than tibia.

Abdomen brown, concolorous with thorax, sclerites of segment 1–3 more thinly sclerotized than remaining segments; T4–6 heavily sclerotized, lateral margin extending ventrally, most pronounced on T4, where stout, rounded ridge formed; S7 produced laterally, overlapping T7; T8 bow-tie shaped, lacking ventral process.

Terminalia ( Fig. 69). Hypandrium with pair of short, slender posterior processes; 1 pair of short anterior, hooked, articulated processes arched posteriorly near surstyli; postgonites arched anteriorly, flanking pair of phallic processes; stout, blade-like, median phallic process arched anteriorly. Epandrial lamella greatly inflated laterally, spherical; fused ventrally to lateral wall of hypandrium. Surstylus curved, finger-like, shorter than cercus. Subepandrial plate subrectangular, heavily sclerotized; more than half length of cercus. Hypoproct with large, lateral process, curving out from beneath cercus; apex round. Cercus heavily sclerotized, with narrow neck and laterally expanded, hammer-shaped apex; posterior tip tapered; cercus clothed in fine setulae, lacking long setae; base of cercus with narrow lobe; apex roundly expanded apically.

Female. Similar to male and female of C. attenuatus except as follows: S7 with transverse weakening, providing flexibility. Terminalia: anterior margin of T8 with flattened, internal, median plate, slightly arched ventrally. S8 subdivided into small trapezoidal sclerite and small, oval dome-shaped sclerite; posterior margin invaginated, forming broad, sclerotized internal plate. T10 bearing stout setae along posterior margin. Cercus broad laterally bearing similar modified setae. Spermathecal receptacle oval, sides parallel-sided, flattened, with short wide neck.

Distribution. The greatest number of specimens of this species have been collected from the Mt. Wilson region of the Blue Mountains ( Fig. 71).

Biology. All specimens at Mt. Wilson were collected along a narrow, cascading stream. This locality is a small remnant rainforest growing in rich basaltic soils, and near the stream is a large grove of tree ferns ( Dicksonia antarctica ), known as the “cathedral of ferns”.

Etymology. The specific name honours Dr D.K. McAlpine, who collected several of the type specimens of this species and first introduced the author to the type locality.