Pseudopomyza (Apops) arenae, Mcalpine, 2019

Mcalpine, David K., 2019, The Genus Pseudopomyza (Diptera: Nerioidea) in Tasmania, with Description of a New Species, Records of the Australian Museum 71 (3), pp. 87-94 : 88-90

Pseudopomyza (Apops) arenae sp. nov.

http://zoobank.org/NomenclaturalActs/ 0475448A-4BA6-428E-8AC5-70FA8EA241F1

Figs 3–12

Holotype ♂. Tasmania: The Neck, Bruny Island [“Penguin Rookery” on some maps, c. 43˚17'S 147˚21'E], 16–18. iii.2005, B. J. Day & D. K. McAlpine ( AM K.493926). Mounted on card point . Paratypes. Tasmania: 1♂, 6♀♀, same data as holotype ( AM K.540941–944, K.556230–231; CNC [with register number K.515414]) .

Description (♂, ♀). Small, shining black moderately robust fly, with clear wings and dark legs.

Coloration. Head largely brown-black, with black bristles; cheek region and parafacial tawny-yellow; lateral facial sclerite largely glossy black; central region of face dull tawny. Antennal segments 1 and 2 tawny-brown; segment 3 slightly darker brown; arista black. Prelabrum and palpus dark brown. Thorax predominantly shining black; mesoscutum rather densely finely pruinescent (thus not glossy as in P. collessi ), scutellum more densely pruinescent dorsally. Wing transparent, without darker shading; setulae on costa black; halter yellow. Coxae dull yellowish; femora largely brown-black; fore femur yellowish at extreme base, other femora more extensively yellowish basally; tibiae dark brown to yellowish; fore tarsus brown, darker in male than in female, particularly basal segment; other tarsi dull tawny. Abdomen subshining black.

Head and eye both higher than long ( Fig. 5 ); postfrons approximately as broad as long, with major bristles large, including ocellar and two fronto-orbitals, with irregularly scattered small setulae but no differentiated interfrontals; anterior margin of postfrons slightly produced medially into a broadly rounded lobe overlapping ptilinum; face broad and almost flat, without setulae, with median submembranous zone widely separating paired lateral sclerites ( Fig. 9 ); cheek c. 0.36–0.38 eye height in profile; vibrissa arising nearer to anterior extremity of cheek in profile than in P. collessi ; large central cheek bristle present.Antennal segment 2 with circlet of setulae on external surface of rim, including several larger ventromedial components and one largest ventral bristle (in P. collessi this circlet of setulae uniformly small except for single very long ventral bristle); arista almost uniformly short-haired, c. 3.7 × as long as segment 3. Prelabrum well sclerotized, shallow and not prominent; palpus small but stout, setulose; labella reduced.

Thorax of moderate proportions; mesoscutum with following bristles well developed: one humeral, 1 + 1 notopleurals, long presutural, 1 + 3 long subequal dorsocentrals, anterior intra-alar bristle absent (in contrast to several foreign species), one short posterior intra-alar bristle (near scutellar suture), two postalar bristles (anterior one shorter); median line of mesoscutum with one or two unpaired bristles; mesopleural and pteropleural bristles absent; one mediumsized sternopleural bristle present; two widely separated pairs of scutellar bristles, posterior ones longer. Wing ( Figs 3, 4 ): costal region with two relatively large but unequal costagial bristles near base, with one or two slightly differentiated bristles basad of humeral break, and pair of relatively prominent bristles at subcostal break; venation otherwise typical of genus.

Male postabdomen ( Fig. 7 ). Tergite 6 large, symmetrical, with few small setulae and, on each side, three large posteroventral bristles; sternite 6 transversely long and slender, strongly arcuate, subsymmetrical, with close series of three posteriorly directed bristles at each lateral extremity; epandrium moderately large, with pair of moderate dorsobasal bristles and few fine setulae; surstylus slender, straight, rod-like, almost bare; cercus moderately prominent, densely setulose.

Dimensions. Total length, ♂ 2.0 mm, ♀ 2.1–2.2 mm; length of thorax, ♂ 0.93 mm, ♀ 0.90–1.1 mm; length of wing, ♂ 2.2 mm, ♀ 2.1–2.4 mm.

(5) head of holotype, male.

Distribution and habitat. Only known from the dunes of Bruny Island, southern Tasmania. This is the same locality and habitat as the type locality of Borboroides gorodkovi McAlpine (2007 , family Heleomyzidae or Heteromyzidae ), but the latter species also occurs in several localities on the Australian mainland. These dunes are densely penetrated by burrows of penguins ( Eudyptula minor ) and shearwaters ( Puffinus sp.) and support only low shrubs and herbage.

Comparative notes. Pseudopomyza arenae differs from P. collessi , the only other described Australian species of the genus, as indicated in the key to species, also in the facial structure (compare Figs 9 and 2 ) and, in the male, in the form of the surstylus and the armature of tergite 6. Of the six New Zealand species described by Malloch (1933) and Harrison (1959; 1976), all except Pseudopomyza flavitarsis (Harrison) differ from P. arenae in having three instead of two pairs of fronto-orbital bristles. Pseudopomyza flavitarsis differs from P. arenae in its largely pale fore tarsus and, in the male, in the presence of a tuft of large bristles on each distolateral extremity of the epandrium.

The specific epithet is a Latin noun in the genitive case–of a sand patch, in reference to the fly’s habitat.

Figures

Figures 3–5. Pseudopomyza arenae. (3) left wing of female. (4) right wing of female, detail of anterobasal section.

Figures 6, 7. Pseudopomyza arenae. (6) holotype male. (7) male postabdomen, left lateral view; scale = 200 μm.

Figures 8, 9. Pseudopomyza arenae, head of female (8) frontal view. (9) facial region.

Figures 10–12. Pseudopomyza arenae, antennae of female. (10) left antennal segment

Figures 1, 2. Pseudopomyza collessi, male, near Geeveston. (1) whole insect. (2) facial view of head.