Bama (Bama) monstrans, McAlpine, 2015

McAlpine, David K., 2015, Signal Flies of the Genus Bama (Diptera: Platystomatidae) in Papua New Guinea, Records of the Australian Museum 67 (2), pp. 25-53 : 48-50

Bama (Bama) monstrans n.sp.

Figs 42–47

Type material. Holotype ♂. Morobe Province: Stony Logging Area, near Bulolo , 765 m [7°15'S 146°40'E], 18.i.1979, H.R., yellow tray ( AM K352858 ) . Paratypes. Morobe Province: 1 ♀, same data as holotype ( AM) ; 2 ♂♂, 1 ♀, Tobo to Salembeng, Huon Peninsula, April 1963, J.S. ( BPB) .

Description (♂, ♀). Moderately elongate blackish fly, with wing darkly marked on distal part only.

Coloration. Head dark tawny-brown to blackish, with silvery-grey pruinescence on postorbital to postgenal zone and on smaller parafacial to fronto-orbital zone. Antenna tawny-orange; arista brown beyond base. Prelabrum brown; palpus brown basally, yellow distally. Thorax: mesoscutum black, with slightly blue-tinted reflections; scutellum black, with slightly blue to purplish reflections; pleura dark tawnybrown. Coxae and femora yellow; tibiae and tarsi dark brown to black. Wing ( Figs 42, 43 ) largely hyaline, with costal, subcostal, and marginal cells and part of submarginal cell yellow; dark brown slightly curved transverse band enclosing anterior crossvein and extending from marginal cell to behind vein 5 but narrowly avoiding anterodistal angle of discal cell; large apical dark brown zone reaching posterior part of discal crossvein and posteriorly fusing with transverse band, slightly more extensive in female than in male, especially in submarginal cell; large part of wing basad of transverse band without distinct brown markings; halter pale yellow. Abdominal tergites black.

Head. Postfrons very slightly narrowed posteriorly, near mid-length 0.38× as wide as head (female); height of cheek 0.19–0.20 of height of eye; face in profile concave above, extensively slightly convex below; in male frontoorbital bristles rather long, ocellar and postvertical bristles very small but distinct, in female all these bristles smaller. Antennal segment 3 c. 2.3–2.4× as long as deep, rounded apically; segment 4 very short, but sclerotised; segment 5 with length not much greater than diameter; segment 6 slightly thickened on basal section, moderately slender on most of length with numerous hairs, many of them at least twice as long as basal diameter of segment. Prelabrum apparently broad and shallow (retracted in type specimens); palpus moderately elongate.

Thorax. Mesoscutum shining, but entirely pubescentpruinescent, more finely so on central part; scutellum finely, densely pubescent on entire dorsal surface; mesopleuron largely glossy, with little pruinescence on dorsal and posterior margins; prescutellar acrostichal bristle rather large. Fore femur with large, stout posteroventral bristles on c. distal half and longer series of moderately large posterodorsal bristles; mid coxa ( Fig. 47 ) with comb of black setulae on margin in addition to numerous non-seriate smaller pale setulae, medially with prominent, non-compressed, almost finger-like lobe bearing one very stout terminal setula; hind basitarsus slender and subcylindrical in both sexes. Wing: first costal cell very largely microtrichose; second costal cell entirely microtrichose; stem vein with narrow dorsal tract of black setulae; vein 2 with slight sigmoid curvature; second section of vein 4 with slight curvature; penultimate section of vein 4 more than half as long as anterior crossvein, less than half as long as discal crossvein; first and second basal cells and anal cell predominantly bare, but second basal cell with narrow microtrichose stripe enclosing small apical bare spot; anal crossvein most strongly curved or bent on anterior half, but slightly variable.

Abdomen. Female: length of compound tergite 1+2 c. 0.67 of that of tergite 3; sternites 1, 2, and 3 large; sternite 4 somewhat smaller; sternites 5 and 6 very short, but sclerotised. Male: sternite 4 with small notch on posterior margin, not cleft; aedeagus ( Fig. 45 ) with preglans ( Fig. 46 ) expanded into subovate, partly membranous lobe bearing many peg-like spinules; flexible section large, longer than glans; glans stoutly ovoid with short distal lobe ensheathing hatchet-like sclerite; bulb rather short; left terminal filament c. half as long as glans, right terminal filament conspicuously smaller.

Dimensions. Total length, ♂ 7.1 mm, ♀ 7.6 mm; length of thorax, ♂ 3.4 mm, ♀ 3.3 mm; length of wing, ♂ 8.7 mm, ♀ 8.1 mm; length of glans of aedeagus, 0.40 mm.

Notes. Bama monstrans differs from other species of the genus in the non-compressed, distally almost finger-like medial prominence of the mid coxa. As in B. papuanum , this prominence has an isolated stout terminal setula. This last feature, together with many features of coloration, suggest a close relationship between B. monstrans and B. papuanum , but the aedeagus of B. monstrans is very distinct from that of B. papuanum and similar in detail to that of B. aurantium .

The specific epithet is a Latin participle, pointing out or indicating, in reference to the finger-like process on the mid coxa.

Figures

Figures 42–44. Bama monstrans n.sp. (42) Holotype male. (43) Right wing of female. (44) Right hind leg of male.

Figures 45–47.Bama monstrans n.sp.(45) Distal part of aedeagus of holotype, right lateral view,scale = 0.3 mm.(46) Preglans from left side, scale = 0.1 mm.(47) Pair of mid coxae of male, left lateroventral view. bu, bulb; fs, flexible section of aedeagus; g, glans; lg, distal lobe of glans; pg, lobe of preglans; st, stipe; tf, terminal filaments.