Pogonortalis monteithi, McAlpine, 2007

McAlpine, D. K., 2007, New Taxa of Signal Flies (Diptera: Platystomatidae) of New Caledonia, Records of the Australian Museum 59 (1), pp. 65-77 : 72

Pogonortalis monteithi n.sp.

Fig. 6

Types. HOLOTYPE?, New Caledonia: Cap Ndoua site 1, rainforest, 150 m, 22°23'S 166°56'E, 21.xii.2004 – 8.i.2005, C.J.B., S.G.W., malaise trap ( PM) . PARATYPE, 1?, Port Boise (Gite Kanua), rainforest, 10 m, 22°21'S 166°58'E, 30.xi.2004 – 1.xii.2004, C.J.B., S.G.W., J.W. ( QM) .

Description. Male (female unknown). Rather small to medium-sized dull blackish fly with few black wing markings, of very similar appearance to the familiar Australian P. doclea (Walker) .

Coloration. Head largely blackish; postfrons tawny-brown anteromedially, with greyish pruinescent orbital margins; face pale greyish pruinescent on somewhat more than upper half; occiput with grey pruinescence, particularly towards orbital margin and vertex. Antenna: segments 1 and 2 tawny-brown; segment 3 rather dark greyish brown. Prelabrum blackish, sometimes partly tawny; palpus dark greyish brown, with slightly paler apex. Thorax with black ground-colour, largely covered with dark grey to whitish pruinescence; scutellum partly tawny, but with entire dorsal surface covered with grey pruinescence; propleuron with pale-pruinescent zone just below spiracle separated from that on posterior margin of coxal foramen. Legs largely dark brown, including fore coxa; segments 1 and 2 of each tarsus yellow, their distal segments tending greyish brown. Wing hyaline, with blackish markings as in Fig. 6 . Halter brown, with parts of base and capitellum paler, tawny-brown. Abdominal tergites and sternites black.

Head. Width of postfrons near its mid-length 0.23–0.24 of width of head; height of cheek 0.06–0.08 of height of eye; lower outline of head capsule not noticeably expanded across cheek regions; single postgenal bristle strongly differentiated from fine postgenal setulae.

Thorax of similar proportions to that of P. doclea and related species; scutellum without setulae; the following bristles present (presence of some inferred from position of sockets): scapulars, humeral, 1 + 1 notopleurals, supra-alar, postalar, posterior intra-alar, one dorsocentral, prescutellar acrostichal, two pairs of scutellars, mesopleural. Wing: venation typical of genus; cell-4 index = 0.38–0.39.

Abdomen, in dorsal view, rounded oval, anteriorly narrowed but not prolonged; tergites 2 to 5 with roughened granular surface. Aedeagus very similar to that of P. doclea (see Steyskal, 1961) and P. howei ; distal end of stipe shortly swollen; preglans short, stout, asymmetrical, set off from both stipe and glans by constrictions; glans very shortly ovoid; terminal filaments long, slender, subequal in length, with slightly expanded apices.

Dimensions. Total length 4.4–5.0 mm; length of thorax 1.7–2.0 mm; length of wing 3.6–4.1 mm; length of glans of aedeagus 0.23 mm.

Distribution New Caledonia: southern part of Grande Terre.

Notes

The males of P. monteithi differ from those of other known Australasian species of Pogonortalis in the absence of broadening of the head capsule and absence of the fascicle of enlarged cheek bristles (see diagrams in McAlpine, 1975). In these respects, even the larger male of P. monteithi more closely resembles the females of the other species. Pogonortalis monteithi further differs from P. hians Schneider and McAlpine in the more restricted wing markings, the more basally located anterior crossvein, and the entirely dull, pruinescent dorsal surface of the scutellum. It differs from P. howei Paramonov and P. doclea (Walker) in having the transverse dark wing stripe from the distal end of vein 1 oblique and meeting vein 4, instead of terminating at vein 3, and in having the whitish-pruinescent zone of the propleuron immediately below the spiracle separate from the pruinescent zone on the posterior margin of the fore coxal foramen. From P. howei it also differs in having antennal segment 3 dark brown, instead of rather bright, deep yellow, in the darker brown fore coxa and femur, and in the absence of a dark blotch at about the basal third of the marginal cell.

The specific epithet refers to Geoffrey B. Monteith, who has encouraged this project and provided much New Caledonian material.

Figures

Figs 5, 6. Wings of signal flies. (5) Eumeka koghii. (6) Pogonortalis monteithi.