Pentachaeta bickeli, McAlpine, 2014

McAlpine, David K., 2014, Review of the Australian Genus Pentachaeta (Diptera: Heleomyzidae), with Descriptions of Nine New Species, Records of the Australian Museum 66 (5), pp. 247-264 : 253-254

Pentachaeta bickeli n. sp.

Figs 11–17

Type material. Holotype ♂. New South Wales: Mount Boyce, near Blackheath , c. 1080 m [33°37'S 150°16'E], 16.iv.1971, D.K.M. ( AM K310592 ). On card point, some legs glued separately to card, postabdomen in genitalia tube on pin . Paratypes. New South Wales: 2♂♂, Kurrajong [Bellbird Corner, c. 33°32'S 150°38'E], Oct. 1966, Dec. 1979, B.J.D., G.A.H., D.S.K., D.K.M. ( AM, ANIC) ; 2♂♂, Wentworth Falls [c. 33°45'S 150°22'E], Nov. 1958, D.K.M. ( AM) ; 1♂, Leura Falls, Blue Mountains , Jan. 1973, D.H.C. ( ANIC) ; 1♂, Sassafras Gully, Springwood [c. 33°43'S 150°33'E], Nov. 1956, D.K.M. ( AM) ; 1♂, Stoney Creek , 5.4 km NNE of Stroud, Dec. 2010, S.F.M. ( AM) ; 1♂, 33 miles [c. 53 km] along Dorrigo–Coramba Road , Apr. 1970, D.H.C. ( ANIC) ; 1♂, Colo Vale [Mittagong district], Mar. 1957, W.W.W. ( USNM) . Females are excluded from the type series because I cannot distinguish them from closely related species.

Other material examined. Queensland: North Mimosa Creek, Blackdown Tableland National Park (Expedition Range), 800 m, Sept. 1992, D.J.B. ( AM, QM) .

Description (male)

Resembling P. edwardsi and related species without sexual dimorphism of tibiae; agreeing with description of that species, except as indicated below.

Coloration generally as for genus; details as given for P. edwardsi .

Abdomen. Surstylus ( Fig. 11 ) elongate, shaped somewhat as in P. edwardsi , nearly parallel-sided from before midlength, hirsute—with many long microtrichia except towards apex, these directed or much sloped towards base, with apex ( Fig. 14 ) on inner surface slightly excavated and with setulae of various sizes, with basal tuft of setulae on elongate, slightly clavate process which is apparently sclerotized all round; subepandrial process and gonostylus ( Fig. 15 ) resembling those of P. edwardsi but rather differently shaped; gonostylus with posteroapical surface roughly pustulose and partly slightly excavate; bulb of aedeagus ( Fig. 16 ) without invaginated conical pits, but, on left lateral surfacemembrane, with many external short, narrow, subparallel sclerotized ridges, each c. 5–8 µm long ( Fig. 17 ); cercus ( Figs 12, 13 ) broadened anteriorly, with angular median projection, and anteroapical lobe gradually narrowed, widely diverging from that of opposite cercus, with surface very generally finely microtrichose approximately to apex of anterior lobe, with large setulae on mid to posterior part, sparser and much smaller anteriorly, anteroapical part with very few small setulae.

Dimensions. Total length cannot be measured; length of thorax, 1.6–1.9 mm; length of wing, 3.9–4.2 mm.

Distribution. New South Wales: mountainous areas in east of state. Queensland: only known from inland ranges, W. of Gladstone district. Map references 6E, 7J, 7K. 8I ( Fig. 4 ).

Notes

Pentachaeta bickeli closely resembles other species with slender, unmodified male hind tibia, largely pale fore tibia, and entirely dark fore tarsus. Male postabdominal characters, particularly the shape of the surstylus, resemble those of P. edwardsi and P. inserta , but the species differs from P. edwardsi in the more elongate setulose tubercle on base of surstylus, in the differently shaped cercus with differently distributed setulae and small, angular medial projection almost level with its ventral surface, and in details of the subepandrial process and gonostylus. It differs from P. inserta particularly in the shape of the cercus and the absence of invaginated subconical teeth on the aedeagus, but these are replaced by numerous minute external ridges ( Fig. 17 ). I am unable to distinguish females from those of related species. The specific epithet refers to Daniel J. Bickel who has collected significant material and given much support to this study.

Figures

Figure 4. Reference map for distribution of Pentachaeta species in eastern Australia. Numbers in each rectangle (2° longitude by 2° latitude) are numbers of recorded species. Map references are given under Distribution for each species.

Figures 11–14. Pentachaeta bickeli, male; (11) surstyli, posteroventral view; minor setulae omitted; scale = 0.2 mm; (12) pair of cerci, left lateral view; setulae shown only on left cercus; scale = 0.1 mm; (13) epandrium with cerci; setulae omitted, except on left cercus; scale = 0.2 mm; (14) apex of left surstylus, inner view; scale = 0.05 mm.

Figures 15–17. Pentachaeta bickeli; (15) left gonostylus and associated structures; detail as for Fig. 10; scale = 0.1 mm; (16) aedeagus, left lateral view; scale = 0.1 mm; (17) part of surface of aedeagal bulb, showing subparallel sclerotized ridges; scale = 0.05 mm.