Acomoptera nelsoni, Kerr, Peter H., 2011

Kerr, Peter H., 2011, Six new species of Acomoptera from North America (Diptera, Mycetophilidae), ZooKeys 137, pp. 41-76 : 58-60

Acomoptera nelsoni sp. n. Figs 1820

Type Material.

Holotype: ♂, "USA: CA: Humboldt Co., Patrick's Point SP, forest behind visitor center MT#1 (6m), 41°08.11'N, 124°09.28'W, ~10masl, 3.iii-10.iv.2008 P.H.Kerr&P.A.Nelson CSCA08L359" / "HOLOTYPE 10F621 ♂ Acomoptera nelsoni Kerr 2011" [red label]. Deposited in CSCA, mounted on gray point, missing ultimate 5 segments of antennae, left front and mid legs, otherwise in good condition. Specimen dissected, male genitalia preserved in DMHF, on card marked "10F621" pinned below specimen.

Paratypes: 3 ♂♂, "Canada: B.C., Upper Carmanah Valley, UTM: 10U CJ 803006, 12-27.viii.1991 N. Winchester, TZ.MT3" [48.67°, -124.69°; CASC]; 1 ♂, "Canada: B.C., Upper Carmanah Valley, 28. viii– 9.ix.1991 N. Winchester, TZ.MT4" [48.67°, -124.69°; CASC].

Diagnosis.

The male gonopods of Acomoptera nelsoni sp. n. are similar to Acomoptera echinosa sp. n., as noted above. The gonostyli of Acomoptera nelsoni , however, are unique in having denticulations arranged in rows, which are present on the inner surface of the gonostyli dorsally (Fig. 20A), in addition to the profile of its form in both dorsal and ventral views (Figs 19 A–B, 20 A–B). The gonocoxal dorsomedial comb is also unique, in being swept back and more narrow than in other Acomoptera species that have this structure (Fig. 20A).

Description.

Male. Body length (n=1): 7.1 mm. Wing length (n=1): 6.0 mm.

Coloration (Fig. 18). Head brown; palpomeres yellowish darkening to brown distally. Antennal scape light brown, pedicel yellowish, base of first flagellomere yellowish, otherwise flagellomeres brown. Thorax cream-colored to brown; scutum brown to dark brown; darker in areas immediately laterad of dorsocentral setae, scutum setae gold- or golden brown-colored; laterotergite and mediotergite light brown to cream-colored. Legs becoming increasingly brown towards tarsi, coxae cream-colored; femur yellowish or cream-colored, tibia yellowish brown to brown, tarsi brown; hind legs lighter in color. Wing hyaline without markings, wing veins brown; haltere stem cream-colored to light brown, knob brown. Abdominal segments concolorous brown, with brown setae. Terminalia yellowish brown to brown.

Head. Ocelli slightly raised; middle ocellus clearly smaller than (approx..25 × size of) lateral ocelli, lateral ocellus located approx. width of ocellus or less from eye margin, separated from median ocellus by approx. twice its own diameter. Eyes with sparse, inconspicuous microsetae, which are approximately as long as width of facet. Face with mostly brown setae, longest of which approx. same length as width of face. Antenna and abdomen elongate (probably) subequal in length. Palpus approx. 1 × width of head (anterior view); palpomere 2 clearly shorter than palpomere 3; palpomere 4 approx. 6 × longer than wide; palpomere 5 approx. 11 × 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.

Male Genitalia (Figs 19-20). Epandrium approx. 2 × wider than long (Fig. 20F). Gonocoxites with developed dorsomedial comb (Figs 20A, 20C). Gonostylus complex, as shown in Figs 19, 20 A–B, 20 D–E.

Female unknown.

Etymology.

The species is named after Peter A. Nelson of Santa Cruz, CA, long-time mentor and friend. He greatly facilitated the collection of this species and many others in the California North Coast region.