Pentachaeta edwardsi, 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 : 251-253

Pentachaeta edwardsi n. sp.

Figs 2 , 3 , 5–10

Type material. Holotype ♂. New South Wales: Mooney Mooney Creek, W. of Gosford , c. 33°26'S 151°15'E, 20.xi.1975, D.K.M. ( AM K310591 ). Glued to card point, postabdomen in genitalia tube on same pin . Paratypes. 28 ♂♂, same locality as holotype, Nov., Dec., Jan. 1975 –1989, D.K.M., B.J.D. ( AM, ANIC, USNM) .

Other material examined. 24 ♀♀, similar data to type material ( AM, ANIC). These are associated with above males. While identification cannot be absolutely confirmed, they are not referable to other species recorded for Mooney Mooney Creek (viz. P. kirkspriggsi , P. physopus ). 1 ♂, Richmond Range, Bonalbo district, Dec. 1991, S.F.M. 8163 ( AM).

Description (male)

Coloration of head, body, and wings as for genus. Antenna and palpus entirely tawny-yellow. Fore femur almost entirely dark brown; mid femur entirely tawny-yellow; hind femur tawny-yellow with dark brown apex; fore and hind tibiae tawny-yellow with brown apices, the latter more strongly browned; mid tibia entirely tawny-yellow; fore and hind tarsi entirely dark brown; mid tarsus tawny-yellow with segments 4 and 5 dark brown.

Thorax. All tibiae slender.

Abdomen. Epandrium usually with two pairs of large dorsal bristles, contrasting with many small setulae; surstylus ( Fig. 5 ) narrowly elongate, slightly broadened basally, with outer surface microtrichose on most of width except on c. distal third, with few, small setulae on parts of outer surface, on inner surface at apex not noticeably excavated, with few larger setulae and numerous minute ones some of which form a curved marginal series; inner armature consisting of low prominence or tubercle located on medial base of surstylus and bearing c. five to seven moderate-sized setulae (accurate count often difficult); subepandrial process ( Fig. 10 ) prominent with c, eight moderately long terminal setulae; gonostylus less prominent with usually three larger setulae and a few minute ones of which little more than their globular sockets are visible, without posterodistal scabrous zone; articulating sclerite with complex apex bearing one rather long setula and few globular sockets; bulb of aedeagus without series of separate sclerites or invaginated teeth on membrane; cercus ( Figs 6, 7 ) anteroposteriorly elongate, of relatively simple form, without special processes (teeth or major tubercles), densely microtrichose except towards anterior extremity, most heavily setulose before midlength, with anterior lobe subtriangular but obtuse, slightly dorsoventrally compressed, with medial margins of two anterior lobes forming a V-shaped sinus; apex of anterior lobe with small to minute setulae, some of latter forming a curved dorsal marginal series.

Dimensions. Total length, 2.2–3.1 mm; length of thorax, 1.3–1.6 mm; length of wing, 3.0– 3.6 mm.

Distribution. Known mainly from the type locality on the northern side of Broken Bay in central eastern New South Wales; one specimen from far north-east of state. Map references 7J, 8H ( Fig. 4 ).

Notes

Among the species with slender, unmodified hind tibia and entirely dark brown to black fore tarsus, males of P. edwardsi may be distinguished by the relatively slender surstylus ( Fig. 5 ), having the basal fascicle of setulae on a short, broad gibbosity, and the anterior lobes of the cerci of simple form, without tubercle, together forming a simple V-shaped sinus, and each strongly setulose except at anterior apex. Females cannot at present be separated morphologically from those of the related species P. bickeli , P. inserta , P. bassiana , and P. gilliesi .

This species is dedicated to Frederick W. Edwards, whose careful editorial work and supplementary illustrations increased the value of J.R. Malloch’s (1933) publication on south-temperate “ Helomyzidae ”.

Figures

Figure 2. Pentachaeta edwardsi. Dorsal view of thorax, showing chaetotaxy. dc, dorsocentral bristles (five pairs); hm, humeral bristle; ia, intra-alar bristle; np, notopleural bristles; pa, postalar bristle; ps, presutural bristle; sa, supra-alar bristle; sc, scutellar bristles.

Figure 3. Pentachaeta edwardsi. Hypandrial structures, ventral view (diagrammatic). aa, aedeagal apodeme; ab, aedeagal bulb; ag, aedeagal guide (connecting aedeagal apodeme to hypandrium anteriorly); as, articulating sclerite; dp, distiphallus; eh, sclerotized extension of hypandrium; fp, fork plate of hypandrium; g, gonostylus; mu, probable muscle attachment; pl, posterolateral extension of basiphallus (partly densely pubescent); sp, subepandrial process (on subepandrial cuticle).

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 5–10. Pentachaeta edwardsi, male; (5) surstyli in situ, posteroventral view; scale = 0.2 mm; (6) oblique posteroventral view of epandrium showing cerci; setulae omitted except on left cercus; scale = 0.2 mm; (7) left cercus, lateral view; (8) apex of right surstylus, inner view; scale = 0.04 mm; (9) anterior apex of right cercus, ventral (outer) view; scale = 0.04 mm; (10) left gonostylus and associated structures, lateral view; scale = 0.1 mm. as, articulating sclerite; g, gonostylus; il, inner lobe of gonostylus; pl, posterolateral extension of basiphallus; sp, subepandrial process (superimposed on other parts in slide preparation).