Acrosathe falcata Webb, 2009

Webb, Donald W., 2009, A revision of the genera Acrosathe Irwin and Lyneborg, Arenigena Irwin and Lyneborg, and Litolinga Irwin and Lyneborg (Diptera: Therevidae: Therevinae) from the Nearctic Region, Zootaxa 2091 (1), pp. 1-67 : 12-14

Acrosathe falcata Webb spec. nov.

(Figs. 9–17, 51)

Etymology. Falcatus (Latin) = sickle-shaped, hooked. This name refers to the sickle-shaped accessory aedeagal process on the male aedeagus and is used as an adjective.

Diagnosis. The male of Acrosathe falcata is similar to A. vialis in having the eyes holoptic, the ommatidia smaller ventrally and laterally, the wing veins and cross-veins lacking a dark brown margin, and having the setae on the head and thorax white to dark yellow. It differs from all other species of Acrosathe in having a falcate-shaped AAP (Figs. 13–15). The female of A. falcata is similar to A. vanduzeei in having the frons with a small dark brown pubescent area dorsolaterally (Fig. 16) but is separated from A. vanduzeei in having the furca quadrate (Fig. 17) with the anterior and posterior margins truncate.

Description of MALE. Variation (n=10).

Body length 6.8–9.1, 7.7 mm.

Head. Length 0.98–1.20, 1.11 mm. Ocellar tubercle dark reddish brown, pubescence gray, dense; setae dark brown, elongate. Eyes holoptic, separated by distance 0.2 times width of median ocellus; ommatidia smaller ventrally and laterally. Frons pubescence gray, dense; setae white, elongate. Antenna dark brown, pubescence white; antenna/head length 0.81–0.90, 0.86; scape length 0.32–0.44, 0.39 mm, width 0.14–0.20, 0.17 mm, length/width 2.0–2.9, 2.3, scape/pedicel length 3.2–4.2, 3.8, scape/flagellum width 0.9–1.4, 1.2, setae white, elongate; pedicel length 0.10–0.12, 0.10 mm, width 0.10–0.16, 0.14 mm, length/width 0.67–0.86, 0.73, setae dark brown, elongate; flagellum length 0.44–0.50, 0.46 mm, width 0.14–0.16, 0.14 mm, length/ width 2.9–3.6, 3.3, flagellum/scape length 1.1–1.4, 1.2. Parafacial pubescence white, dense; setae white. Maxillary palpus dark reddish brown, pubescence white; length 0.46–0.64, 0.55 mm, width 0.06–0.10, 0.08 mm, length/width 5.8–8.7, 6.8; setae white, elongate. Genal setae white, elongate. Occipital setae white, elongate; macrosetae dark brown, sparse. Postocular macrosetae dark brown.

Thorax. Macrosetae 3 np, 2 sa, 1–2, 1 pa, 0–2, 1 dc. Mesonotum pubescence gray, dense, vittae indistinct; setae white, elongate, erect with scattered brown setae. Postpronotal lobe setae white, elongate. Prosternum setae white. Pleuron pubescence white, dense; setae white, elongate on propleuron, anepisternum, katepisternum, laterotergite, metanepisternum, and scutellum. Wing. Membrane hyaline, veins brown; length 5.3–7.3, 6.3 mm, width 1.7–2.7, 2.1 mm, length/width 2.7–3.3, 3.0; pterostigma brown, narrow. Cell m 3 closed, petiolate. Halter stalk brown, knob pale yellow. Legs. Coxal pubescence white, dense; setae white, elongate; apical macrosetae dark brown, hindcoxa with 1 posterolateral macroseta. Femora dark reddish brown; ventral setae white, elongate, dorsal appressed setae white. Tibiae dark yellowish brown becoming darker on apical half. Tarsus 1 dark yellow becoming dark reddish brown on apical half; 2–5 dark reddish brown.

Abdomen. Dark brown, pubescence silver gray, dense; dorsal setae white, elongate, appressed; lateral setae white erect. Terminalia (MEI 012275) dark brown, pubescence white, dense. Tergite 8 (Fig. 9), setae white. Sternite 8 (Fig. 10), rectangular, sides tapered posteriorly, posterior margin emarginate; setae white, thick, absent medially on posterior margin. Epandrium (Fig. 9) quadrate, sides rounded, longer medially than wide; posterolateral margin projecting posteriorly, pointed; setae white. Cerci (Fig. 9), ending above apex of hypoproct. Hypoproct (Fig. 9), apex truncate, ending distal to posterolateral margin of epandrium, below apex of cerci. Gonocoxite ventral view (Fig. 10) rectangular, median margin straight, posterior margin scalloped, setae dark white, macrosetae dark brown on posterior margin and inner gonocoxal process; lateral view (Fig. 11) quadrate, posterior margin scalloped. Gonostylus, dorsal view (Fig. 12), flattened dorsoventrally with large dorsomedial carina and lateral pointed projection, setae pale yellow. Aedeagus with dorsal apodeme (Fig. 13) rectangular, sides parallel, anterior margin truncate; ventral apodeme (Fig. 14) broad, clavate with large ventral carina, reaching anterior margin of dorsal apodeme; distiphallus dorsal view (Fig. 13) broad, tapered posteriorly; lateral view (Fig. 15) tapered ventrally in broad curve; AAP unique, falcate with narrow attachment laterally to side of ventral apodeme and ventrally to ventral lobe; ejaculatory apodeme (Fig. 13), reaching anterior margin of dorsal apodeme.

FEMALE. Similar to male except for following. Variation (n=10).

Body length 7.2–9.3, 8.3 mm.

Head. Length 0.98–1.18, 1.05 mm. Frons pubescence white, dense on ventral third, yellowish brown pubescence dorsally with small, dark brown, pubescent area dorsolaterally (Fig. 16) which may extend as a bar across frons (MEI 012065 Mt. Shasta); setae white to pale yellow, elongate ventrally and dark brown dorsally. Antenna/head length 0.80–1.10, 0.93; scape length 0.34–0.46, 0.39 mm, width 0.15–0.20, 0.18 mm, length/width 2.0–2.5, 2.2, scape/pedicel length 3.3–4.2, 3.8, scape/flagellum width 1.0–1.4, 1.2; pedicel length 0.10–0.11, 0.10 mm, width 0.14–0.16, 0.15 mm, length/width 0.6–0.8, 0.7; flagellum length 0.42–0.52, 0.46 mm, width 0.14–0.17, 0.15 mm, length/width 2.6–3.3, 3.1, flagellum/scape length 1.0–1.3, 1.2. Maxillary palpus length 0.52–0.66, 0.59 mm, width 0.08–0.12, 0.09 mm, length/width 5.3–8.3, 6.5.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 1–2 dc. Wing. Length 5.7–7.7, 6.4 mm, width 1.7–2.3, 2.1 mm, length/width 2.9–3.5, 3.1.

Abdomen. Dark brown, pubescence gray, anteromedial area of tergite dark brown; dorsal setae white becoming pale yellow posteriorly. Terminalia (MEI 012065) dark reddish brown, glossy. Furca (Fig. 17) quadrate, constricted posteriorly, anterior margin truncate; length 0.64 mm, width 0.48 mm; anterolateral projection short, pointed.

Immature stages. Unknown.

Distribution. Acrosathe falcata is known from California, Nevada, and Utah ( Fig. 51 ).

Habitats and Phenology. Acrosathe falcata has been hand-netted and collected on Salix lasiolepis Benth. Adults have been collected in June through August.

Specimens examined. Type specimens. The holotype male (MEI 012271) of Acrosathe falcata Webb , spec. nov. is labeled "Mt. Rose, summit Nev., Washoe Co., VII-9-1964, M. E. Irwin Collector" and is deposited in the CAS ( CAS Type No. 18349). PARATYPES. UNITED STATES. CALIFORNIA. 4.8 km SE Mount Lassen, 8.VII.1955, MacSwain, J.W., 1♂ MEI 012143, 1♀ 157898 ( EMEC) ; Mount Shasta [41.31, - 122.309], 2438m, 3.VIII.1958, Powell, J., 2♂ MEI 012061, 012072, 1♀ 012065 ( EMEC) . Alpine County. Winnemucca Lake [38.669, -119.991], 14.VII.1964, Gillogly, A., 1♂ MEI 012459 ( UCR) , on Salix lasiolepis . El Dorado County. Grass Lake [38.794, -119.964], 5.VII.1962, Gill, R.J., 1♀ MEI 011674 ( UCDC) ; Riverton [38.771, -120.449], 20.V.1955, Wasbauer, M., 1♂ MEI 011515 ( UCDC) ; China Flat [28.VI.1948], Hurd, P.D., 1♀ MEI 012090 ( EMEC) . Mariposa County. Fish Camp [37.479, -119.639], 10.V.1942, Linsley, E.G., 1♂ MEI 012036, 1♀ 012041 ( EMEC) . Nevada County. near Hobart Mills [39.401, -120.183], 17.VI.1964, Bohart, R.M., 1♀ MEI 011678 ( UCDC) ; Sagehen Creek [39.477, -120.131], 25.VI.1966, Bohart, R.M., 1♂ MEI 011668 ( UCDC) ; 22.VI.1972, Belmont, R.A., 1♀ MEI 012610 ( MEIC) ;?. VI.1974, Bugg, R.I., 1♂ MEI 012609 ( CSCA) ; 19.VI.1974, 1♂ MEI 012613 ( UCDC) ; 30.VI.1976, Villegas, B., 1♀ MEI 116853 ( UCDC) ; 25.VI.1978, Brooks, R.W., 1♂ MEI 116856 ( UCDC) . Placer County. Carnelian Bay, Lake Tahoe [39.167, -120.143], 13.VI.1957, Bohart, R.M., 1♀ MEI 011679 ( INHS) ; 12.VI.1965, Parker, F.D., 2♀ MEI 011676 ( UCDC) , 011677 (CSCA). Riverside County. Riverside, Santa Ana River , 2.IV.1964, Irwin , M.E., 1♀ MEI 012273 ( MEIC) . Shasta County. [Lassen Peak], Lassen Peak Trail [40.488, -121.504], 14.VII.1947, Adams, D.W., 1♂ MEI 012084, 1♀ 012091 ( MEIC) ; Leigh , T.F., 1♂ MEI 011682, 1♀ 011681 ( INHS) . Sierra County. Independence Lake [39.452, -120.289], 16.VII.1958, Bohart, R.M., 1♀ MEI 011680 ( UCDC) .

Siskiyou County. Mt. Shasta [41.31, -122.309], 2438–2743m, 21.VII.1966, Powell, J., 1♂ MEI 053214

(EMEC); Mt. Shasta Ski Lodge [41.322, -122.202], 2438m, 6.VIII.1967, Arnaud, P.H., Jr., 1♂ MEI 157188 ( CAS) . Tulare County. Alta Meadow [36.578, -118.654], 2743m, 19.VII.1907, Bradley, J.C., 1♂ MEI 075589, 1♀ 075588 ( CUIC) . NEVADA. Washoe County. Mount Rose [39.344, -119.916], 1981m, 14.VI.1957, Bohart, R.M., 1♂ MEI 012616 ( UCDC) ; Pyramid Lake [39.862, -119.435], 27.VI.1972, Belmont, R.A., 1♂ MEI 011562 ( UCDC) ; 23.VI.1976, Bortfeld, C.M., 1♀ MEI 116855 ( UCDC) ; 9.VII.1964, Bohart, R.M., 1♂ MEI 011664 ( INHS) , 1♀ 011669 ( UCDC) ; Irwin , M.E., 3♂ MEI 011675, 012270 ( MEIC) , 012275 (USNM), 2♀ 012268 ( MEIC) , 012269 (USNM); Kovacic , C.R., 1♂ MEI 011663, 1♀ 011673 ( UCDC) ; Parker , F.D., 3♂ MEI 011665–7 ( UCDC) , 2♀ 011671–2 ( UCDC) ; Veirs , D., 1♂ MEI 072788 ( EMUS) . UTAH. Piute County. Circleville [38.172, -112.27], 21.V.1996, Knowlton, G.F., 1♀ MEI 072797 ( EMUS) ; 1.VI.1996, 1♂ (MEI 072798 ( EMUS).

Figures

FIGURE 50–53. Distribution map. 50. Acrosathe bimaculata closed circle, Arenigena floridensis closed triangle, Litolinga tergisa open circle. 51. Acrosathe falcata closed circle, Ac. pacifica open circle. 52. Acrosathe otiosa. 53. Acrosathe vanduzeei.