Acomoptera forculata, Kerr, Peter H., 2011

Kerr, Peter H., 2011, Six new species of Acomoptera from North America (Diptera, Mycetophilidae), ZooKeys 137, pp. 41-76 : 54-57

Acomoptera forculata sp. n. Figs 1517

Type Material.

Holotype: ♂, "7 Mi. E. Griffith, Ont., 31.v.1983, B.E. Cooper" [45.181°, -77.237°] / "HOLOTYPE 11G479 ♂ Acomoptera forculata Kerr 2011" [red label]. Deposited in CNC, specimen glued directly to the pin, missing last left antennal segment, right front leg, and left hind leg. Otherwise in excellent condition.

Paratypes: 1 ♂, same data as holotype [CNC]; 1 ♂, "N.S., CBHNt.Pk., Mackenzie Mt., 400m PG639848, 27.V.1984 / birch & fir, B.E. Cooper" [46.738°, -60.650°; CNC]; 1 ♂, same data, except collected 28.V.1984 [CNC]; 1 ♂, same data, except collected 7.VI.1984 [CNC]; 2 ♂, "N.S., CBHNt.Pk., Pleasant Bay PG682873, 6.VI.1984 / mixed forest, B.E. Cooper" [46.738°, -60.650°; CNC]; 1 ♂, "N.S., CBHNt.Pk., North Mt. Bog PG767865, 3.VI.1984, B.E. Cooper" [46.738°, -60.650°; CNC]; 2 ♂♂, "N.S., C.B.N.P., Black Brook, 2-4-VI-1983, Herbs QG035833 6.VI.1984" [46.738°, -60.650°; CNC]; 1 ♂, "Kouchibouguac N.P., N.B., 18.VI.1977, G.A. Calderwood" [46.814°, -64.928°; CNC];

Diagnosis.

This species is unique in the genus for having a forked hypandrial lobe (Fig. 16D). The form of the gonostylus (Fig. 17D) is reminiscent of that displayed by Acomoptera difficilis (Fig. 5D), but the posterior-projecting ventrolateral process is significantly shorter (Fig. 17E).

Description.

Male. Body length (n=7): 4.5-5.6 mm (avg = 5.0 mm). Wing length: 4.1-4.7 mm (avg = 4.4 mm).

Coloration (Fig. 15). Head brown; palpomeres yellowish light brown. Antennal scape brown, pedicel yellowish light brown, base of first flagellomere yellowish light brown, remaining flagellomeres slightly darker. Thorax mostly brown; scutum uniformly brown to dark brown and/or area of acrostichal setae darkened, areas laterad of dorsocentral setae with darker brown markings, scutum setae gold- or golden brown-colored; laterotergite and mediotergite light brown to brown. Legs darkening towards tarsi (although in some cases, hind legs less so), coxae yellowish or cream-colored; femur yellowish light brown, tibia and tarsi light brown to brown. Wing hyaline without markings, wing veins light brown; haltere stem and knob cream-colored to light brown. Abdominal tergites 2-5 brown, with posterior margins yellowish or cream-colored; other segments concolorous brown; abdomen with golden brown setae. Terminalia yellowish brown to brown.

Head. Ocelli slightly raised; middle ocellus slightly smaller than (approx. 0.6-0.8 × size of) lateral ocelli, lateral ocellus located approx. width of ocellus from eye margin, separated from median ocellus by 2 –3× its own diameter. Eyes with sparse, inconspicuous microsetae, which are approximately as long as width of facet. Face with brown setae, longest of which approx. same length as width of face. Antenna approx. 0.75 –0.9× length of abdomen. Palpus approx. 0.7 × width of head (anterior view); length of palpomeres 2 and 3 nearly subequal (palpomere 3 longer); palpomere 4 approx. 4 × longer than wide; palpomere 5 approx. 6 × longer than wide, subequal to or shorter than combined length of palpomeres 3 and 4.

Thorax. Antepronotum bearing setae; remaining thoracic sclerites bare. Wing venation similar to others in the genus (e.g., Acomoptera digitata sp. n., Fig. 8); costal vein extends beyond R5, approx. 0.33 × distance between R5 and M1; R1, R5, and M1 with at least some setae on lower surface (although often lacking on M1).

Male Genitalia (Figs 16-17). Epandrium slightly wider (1.3x) than long (Fig. 17F). Gonocoxites with dorsomedial structure bearing elongated lobes, not developed as dorsomedial comb (Figs 17A, 17C). Hypandrial lobe present, forked (Fig. 16D). Gonostylus complex, as shown in Figs 16, 17 A–B, 17 D–E.

Female unknown.

Etymology.

The species epithet "forculata" is an arbitrary combination of letters alluding to the prominently forked hypandrial lobe.