Acomoptera digitata, Kerr, Peter H., 2011

Kerr, Peter H., 2011, Six new species of Acomoptera from North America (Diptera, Mycetophilidae), ZooKeys 137, pp. 41-76 : 48-50

Acomoptera digitata sp. n. Figs 611

Type Material.

Holotype: ♂, "USA, Oregon, Curry Co., small seep (#2) on Elko road, 42°23.122'N, 124°13.736'W 925m, 2.vi.2009 G. Courtney CSCA09L472" / "HOLOTYPE 09D070 ♂ Acomoptera digitata Kerr 2011" [red label]. Deposited in CSCA, complete specimen in excellent condition, mounted on gray point.

Paratypes: 10 ♂♂, 1♀ "USA: CA: Del Norte Co, SixRiversNF, ForRoute16N02, nr. BearBasin Outlk, 41.8016°N, 123.7369°W, 1500masl, 3.vi-24.vii.2009 P.H.Kerr & O.Lonsdale, 6m MT, CSCA09L526" [CSCA].

Diagnosis.

This species may be distinguished from all other Acomoptera species by the dorsoventrally elongate suboval shape of the gonostylus, which features a prominent, finger-like lobe that projects inward (Fig. 11D) and a ventral, posterior-protruding lip that bears an elongate, narrow process (Figs 11 D–E).

Description.

Male. Body length (n=6): 5.2-6.4 mm (avg = 5.9 mm). Wing length: 5.0-6.1 mm (avg = 5.6 mm).

Coloration (Figs 6A, 7). Head brown; palpomeres light brown. Antennal scape light brown, pedicel and flagellomeres yellow to yellowish brown. Thorax variously brown to cream-colored, in parts; pair of darker brown markings on scutum laterad of dorsocentral setae, scutum setae gold- or golden brown-colored; antepronotum, proepisternum, and proepimeron dark brown, anepisternum, katepisternum, and meron brown; anepimeron cream-colored and noticeably lighter in color than surrounding sclerites; laterotergite brown; metanepisternum and metakatepisternum brown to dark brown; mediotergite brown centrally, cream-colored laterally. Legs becoming increasingly brown towards tarsi, coxae cream-colored (coxal setae yellow); femur yellowish or cream-colored, tibia yellowish brown, tarsi light brown. Wing hyaline without markings, wing veins light brown; haltere stem and knob cream-colored to yellowish brown. Abdominal segments concolorous, brown, with golden brown setae. Terminalia yellowish brown to brown.

Head. Ocelli slightly raised; middle ocellus smaller or about the same size as lateral ocelli; lateral ocellus located approx. its own width (approx. width of two eye facets) 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. Antennal length approx. 0.75 × length of abdomen. Palpus shorter than width of head (anterior view); palpomere 2 clearly shorter than palpomere 3; palpomere 4 approx. 3 × longer than wide; palpomere 5 approx. 6 × longer than wide, shorter than combined length of palpomeres 3 and 4.

Thorax (Fig. 7). Antepronotum bearing setae; remaining thoracic sclerites bare. Tarsal claw usually with two small ventral teeth. Wing venation as in Fig. 8; costal vein extends beyond R5, approx. 0.25 × distance between R5 and M1; R1, R5, and M1 with at least some setae on lower surface.

Male Genitalia (Figs 10-11). Epandrium approx. 2 × wider than long (Fig. 11F). Gonocoxites without developed dorsomedial comb (Figs 11A, 11C). Gonostylus complex, as shown in Figs 10, 11 A–B, 11 D–E.

Female. Body length (n=1): 5.9 mm; wing length (n=1): 5.6 mm.

As male in all aspects except the following:

Generally moderately darker than male (Fig. 6B). Antennal scape brown, pedicel and flagellomeres light brown, yellowish brown, or brown. Scutum setae black. Legs becoming increasingly brown towards tarsi, coxae light brown (coxal setae black); fore femur yellowish or cream-colored, mid and hind femora light brown or brown; tibia and tarsi brown to light brown. Wing membrane darker and wing veins stronger than in male; abdominal setae black. Terminalia yellowish or yellowish light brown, form as in Fig. 9.

Comment.

The female specimen was united with males on the basis of similar coloration patterns (e.g., bicolored mediotergite) and having been collected with males at a locality known only for this species.

Etymology.

The species epithet "digitata" is an adjective derived from the Latin word for finger, referring to the adaxial process of the gonostylus.