Ceratomerus malleolus, 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

Ceratomerus malleolus n.sp.

Figs. 41, 54, 55, 58, 64–68, 71

Type material. HOLOTYPE 3, “VIC[toria, Australia ]: Acheron Creek; 29 km / from Warburton; pans/ rainforest/creek; 400 m / 1–3.xii.1994; D. Bickel ”; “ HOLOTYPE / Ceratomerus / malleolus / Sinclair [red label]” AMS K175246 . PARATYPES: New South Wales: 13, Kosciusko NP, Pipers Ck, Guthega Rd , 1320 m, subalpine, 1.i.1991, DJB ( AMS) . Victoria: 1♀, same data as holotype, BJS ( ZFMK) ; 1333, 6♀♀, same data as holotype ( AMS, CNC, ZFMK); 13, Otway NP, Blanket Bay ; rocky ck above falls, 10 m, 4–5.xii.1994, y.pans, DJB ( AMS) .

Diagnosis. Recognized by the slight inflexion of R 2+3 around the stigma, heavily sclerotized male tergites 4–6 and anvilshaped male cercus. This species can be distinguished from its sister species, C. macalpinei , by the narrow setose lobe beneath the cercus. Females can be partially identified by the brown pleura and long style.

Description. Wing length 3–3.5 mm, similar to C. attenuatus except as follows:

Male. Head. Postocellar bristles one-third length of ocellar bristles. Antenna with length of scape slightly less than height of eye ( Fig. 58); 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 occasionally extending ventrally along proepisternum.

Wing ( Fig. 54) as in C. attenuatus .

Legs. Fore and mid coxae pale and ventral margin of femora yellowish-brown, 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 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 ( Fig. 41). Mid tibia not swollen at mid-length, with av row of short setae; pv surface with row of slender setae, longer than width of tibia; ventroapically with row of short erect setae on apical sixth; 1 ad seta on proximal half. First tarsomere subequal in length to remaining 4 tarsomeres, with many erect pv setae.

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 4 long, erect setae. Hind tarsomeres slightly longer than tibia.

Abdomen pale brown, concolorous with thorax, sclerites of segment 1–3 weakly sclerotized; T4–6 heavily sclerotized, lateral margin extending ventrally, most pronounced in T4, where stout, rounded ridge formed ( Fig. 68); S7 produced laterally, overlapping T7; T8 bow-tie shaped, lacking ventral process.

Terminalia ( Figs. 66, 67). 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, with hooked apex. 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; clothed in fine setulae, lacking long setae; base of cercus with slender setose lobe.

Female. Similar to male and female of C. attenuatus except as follows: wing similar to male, although often R 2+3 more strongly deflected below stigma ( Fig. 55). S7 with transverse weakening, providing flexibility. Terminalia ( Fig. 64): anterior margin of T8 with flattened, internal, median plate, strongly arched ventrally. S8 subdivided into small trapezoidal sclerite and small, oval dome-shaped sclerite; posterior margin invaginated, forming broad internal plate. T10 bearing stout setae along posterior margin. Cercus bearing similar modified setae. Spermathecal receptacle oval, flattened, with distinct wide neck ( Fig. 65).

Distribution. This species is known from Victoria and New South Wales ( Fig. 71), in subalpine to coastal habitats.

Etymology. The specific name is from the Latin malleolus (hammer), referring to the shape of the male cercus.