Dasysyrphus pacificus (Lovett)

Locke, Michelle M. & Skevington, Jeffrey H., 2013, Revision of Nearctic <i> Dasysyrphus </ i> Enderlein (Diptera: Syrphidae), Zootaxa 3660 (1), pp. 1-80 : 55-58

Dasysyrphus pacificus (Lovett)

Figures: 13A–D, 21C

Synonyms and References:

Syrphus pacifica Lovett 1919: 245 (in ( Cole & Lovett 1919); original description)

Metasyrphus pacifica (Lovett) :

Fluke 1933: 116 (key, redescription and transfer to Metasyrphus )

Dasysyrphus pacificus (Lovett) :

Stone et al. 1965: 564 (catalogue and transfer to Dasysyrphus )

Dasysyrphus pauxillus (Williston) :

Vockeroth 1986: 203 (in part; synonymy)

Vockeroth 1992: 68 (in part; key and redescription)

Diagnosis: Abdominal maculae of tergites 3&4 slightly arcuate, uniform in thickness and do not cross abdominal margin ( Figs 13A & B ); very similar in appearance to D. pauxillus ( Fig. 14A ), D. nigricornis ( Figs 11A & B ) and D. laticaudus ( Fig. 8A ). Wing typically much more bare than any of the three aforementioned species, with cells br and bm with large dense areas ( Fig. 13C ). Male gonostylus with narrow, wavy projection on posterodorsal surface (arrow, Fig. 13D ). Due to an extremely similar habitus, it is difficult to distinguish D. pacificus from D. pauxillus . Male genitalia should be used to conclusively identify specimens, especially in the overlap zone of these species’ ranges in southern British Columbia.

Redescription:

Body Length: 5.0– 8.5mm; Wing Length: 5.0– 7.7mm

Head: Frons dark with light pollenose fascia (in males it runs along ventral edge of where eyes meet, in female it is ½ the length between the antennae and ocelli) and dark pile; face light with dark vitta ¼ the width of the face, reaching antennal socket, face with dark pile; gena dark with some light pollen ventral to eye, dark pile dorsally and light pile ventrally; occiput dark, covered in light pollen, pile light with some dark pile dorsally; scape, pedicel and flagellomere light to dark.

Thorax: Scutum dark, may appear shiny or metallic, pile light; scutellum light to dark with darker anterior and lateral edges, light pile with some dark pile posteriorly; wing cell br bare above spurious vein and usually on basal half, bm bare medially or basal half, cells c and r 1 bare at base or with at least small bare areas at base, cup call has small bare areas along vein CuP, wing less frequently completely microtrichose ( Fig. 13C ); haltere light to dark; pro- and mesofemora ⅓–½ dark basially, ½–⅔ light apically, metafemur ⅔–¾ dark basially, ¼–⅓ light apically, tibiae light, metatibia with dark band ¼ of the way from the apex, tarsi light, sometime dark anteriorly.

Abdomen: Maculae on tergite 2 large, slender and oval, ⅓–½ width of tergite, maculae on tergites 3&4 are slightly arcuate, uniform in thickness, with out a distinct swelling medially, maculae do not reach abdominal margin ( Figs 13A & B ); sternites light with dark fasciae.

Male Genitalia: Surstylus more or less triangular in shape in lateral view, flattened posteriorly, long pile on dorsal, laterodorsal and posterodorsal sides, row of spines on posteromedial edge; cercus oval with long pile over entire surface; gonostylus triangular-shaped with narrow, wavy projection on posterodorsal surface projecting posterodorsally, pile on dorsal surface; basiphallus elongate, basally bent at 90 degree angle towards dorsum, apical end curved ventrally with a widened apex and is partly membranous dorsally, with spines on posterodorsal side; distiphallus elongate, apical end flared out into horn, which is mostly sclerotized but membranous at apex with few minute setulae dorsally, basally bent towards dorsum and usually greatly enlarged at bend with a triangular projection, projecting ventrally ( Fig. 13D ).

Intraspecific variation: Distiphallus sometimes without triangular projection basally. Abdominal maculae on tergites 3 & 4 rarely meet medially, and if so, barely touch.

Etymology: Pacificus is Latin for peaceful or peace-making, but more probably was named so because this species is found along the Pacific coast of North America.

Distribution: Southwestern USA (CA, NV, OR, WA) and southwestern Canada (BC); Cascades and Sierra Nevada Mountain Ranges ( Fig. 21C ).

Ecology:

Collected from April-July, but more commonly in May and June, at elevations of 475–3100m. Recorded from willow ( Salix Linnaeus , Salicaceae ) and bitterbush ( Purshia de Candolle ex Poiret , Rosaceae ).

Discussion: Dasysyrphus pacificus is hereby resurrected from synonymy with Dasysyrphus pauxillus (synonymized by Vockeroth (1986)). The type specimen of this species could not be examined as it is out on loan to another individual. However, based on the written description and distribution of D. pacificus ( Cole & Lovett 1919) the authors are confident that the individuals examined were of this species. The range of pacificus is from southern British Columbia, south to California , in the Cascades and Sierra Nevada mountain ranges . The type specimen is from Oregon, where it is the only species of the pauxillus s.l. in this range.

Type Material: “ Holotype (No. 502), male, in Museum of the California Academy of Sciences, collected at Corvallis, Ore., May 17, by A. L. Lovett” ( Cole & Lovett 1919). (not examined)

Material Examined:

Canada: British Columbia: Bear Mountain , [49.300555, -121.740556], 6.v.1920, ♂, CNCD 13743 , ( CNC). EAST KOOTENAY R . D.: Cranbrook , [49.517983, -115.761504], 19.v.1920, ♂, CNCD 13748 , C.B.D. Garrett ( CNC); 27.iv. ♂, RBCM ENT 99188108 , H. R. Foxlee ( RBCM). 7 miles N Lions Bay, North of Vancouver , 18.v.1979, ♂, CNCD 5464 , G.F. Hevel ( USNM) . United States of America: California: RIVERSIDE CO. : Dark Canyon N of Idyllwild, [33.81666667, -116.7166667], 24.v.2003, CNCD 8472 , J. Skevington ( CNC). SAN BERNARDINO CO .: Upper Santa Ana River , [34.091253, -117.120741], 3.vi.1947, ♀, CNCD 26415 , G.H. & J.L. Sperry ( CNC). 1 km NW Wrightwood, Big Pines Hwy, [34.38138889, -117.6716667], 1974m, 21–28.v.2005, 5♂, JSS 20974, 20976–20978, 20980, 2♀, JSS 20975, 20979, A. R . Cline & S.L. Winterton ( MHPC). Oakhurst , [37.328, -119.649315], 1.vi.1942, ♀, JSS 20598, E.C. Linsley ( EMEC). TUOLUMNE CO .: Mather Site, Buck Meadows , [37.880173, -119.856977], 1970, ♂, CNCD 26437 , 4♀, CNCD 26404–26407 , A. R. Moldenke ( CNC). MARIN CO .: Lily Pond, Alpine Lake , [37.953803, -122.634977], 457m, 25.v.1970, ♀, CNCD 26414 , 11.iv.– 25.v.1971, ♂, CNCD 26344 , D.D. Munroe ( CNC). CALAVERAS BIG TREES SP: S. grove, banks of Beaver Creek , MT#2 , [38.26166667, -120.2577778], 1375m, 22.v.–11.vi.2007, 6♀, JSS 20966–20970, 20972, A. R . Cline & P.H. Kerr ( MHPC). INDIAN GRINDING ROCK SP: dry wash nr. S. Nature Trail MT #2 , [38.41666667, -120.6333333], 715m, 5.iv.–24.iv.2007, JSS 20981, ♀, JSS 20992, P. Kerr & M. Hauser ( MHPC); firebreak nr. envtl camp MT3 , [38.41861111, -120.635], 715m, 24.iv.2007 24.v.2007, ♀, JSS 20971, P. Kerr & M. Hauser ( MHPC). Sonora Pass, [38.53666667, -119.6855556], 3100m, 21.vi.2007, ♀, JSS 20963, S.M. Blank ( MHPC). Wright’s Lake, [38.84913, -120.2318], 2.vii.1948, ♂, JSS 20597, D. Carter ( EMEC); 2.vii.1948, ♀, JSS 20601, L.W. Quate ( EMEC). Placer County, [39.090423, -120.803069], 1524m, iv, ♀, JSS 19511, W.M. Davidson ( CNC). Tahoe City, Alpine Meadow Road Jenkinson Reservoir, [39.42138889, -120.3333333], 2200m, 14.vi.2007, ♂, JSS 20957, ♀, JSS 20958, S.M. Blank ( MHPC). Sinkyone Wilderness State Park , [39.83583333, 123], 28m, 23.iii.2003, ♂, JSS 20797, J. & A. Skevington ( CNC). PLUMAS CO .: Buck’s Lake , [39.890961, -121.185778], 13.v.1949, ♀, CNCD 26409 , P.D. Hurd ( CNC), 4♂, CNCD 26432–26435 , ♀, CNCD 26410 , W.W. Middlekauff ( CNC); 23.vi.1949, 2♀, CNCD 26412 , D. Cox ( CNC), ♀, CNCD 26413 , J.W. MacSwain ( CNC); 13.v.1949, ♂, JSS 20594, E.O. Essig ( EMEC), ♂, JSS 20595, ♀, JSS 20603, P.D. Hurd ( EMEC); 23.vi.1949, 2♀, JSS 20599, 20600, J.W. MacSwain ( EMEC). TEHAMA CO .: 60 kilometers North East of Chico on Road 32, [40.19611111, -121.5213889], 1100m, 15.v.2010, JSS 25002, 25003, 25005–25009, D. Striley, M. Hauser ( CSCA). LASSEN CO .: Susan River Campground , [40.492316, - 121.094484], 9.vii.1949, ♀, CNCD 26411 , A. T. McClay ( CNC). SHASTA CO .: Viola , [40.517921, -121.680971], 19.v.1941, ♂, CNCD 26436 , ♀, CNCD 26408 , E.G. Linsley ( CNC). LASSEN NATIONAL PARK : Manzanita Lake, [40.534513, 121.56655], 8.vi.1941, ♀, JSS 20596, C.D. Michener ( EMEC), ♀, JSS 20602, Arthur J Walz ( EMEC). Ryan Creek , 17.v.1938, ♀, CNCD 106796 , N.F. Hardman ( CNC). San Bernardino Mountains; Up Sta. Ana River, 15.vi.1955, ♀, JSS 23775; 1957, ♀, JSS 26926, A.L. Melander ( USNM). Nevada: WASHOE CO. : Little Valley , [39.806851, -119.951585], 4.vi.1981, JSS 25100, R . W. Rust ( EMUS). Oregon: KLAMATH CO .: Lake of the Woods , [42.368634, -122.208482], 22.vi.1975, JSS 25082–25086, 25088–25095, G.F. Knowlton ( EMUS), ♀, CNCD 5457 , G.F. Knowlton ( USNM); Summit Lake , [43.454905, -122.118766], 7.vii.1952, ♂, CNCD 26442 , E. R. Jaycox ( CNC). DESCHUTES CO .: Camp Abbot , [43.874555, -121.435449], 4.vi.1944, ♀, CNCD 26401 , P.H. Arnaud ( CNC). Bellfountain , [44.363611, -123.355278], 27.v.1922, ♂, OSAC 133389 , 133391 , A.L. Lovett ( OSAC). BENTON CO .: Corvallis , [44.564564, -123.262033], v.1977, ♂, JSS 19507, A.L. Lovett ( CNC) .

Washington: WENATCHE NATIONAL FOREST: White Pass Trail , [46.643317, 121.378783], 1345m, 6.vii.2010 , CNCD 60054 , A. Young ( CNC), ♂ , CNCD 35314 , ♀ , CNCD 35313 , M.M. Locke ( CNC). Mount Rainier , [46.853048, -121.753127], ♂ , CNCD 26429 , ♀ , CNCD 26400 , 26419 , F.M. Hull ( CNC). SAN JUAN CO.: Olga , [48.619548, -122.835459], 18.v.1910, ♀ , JSS 19504, ( CNC) . MOUNT BAKER- SNOQUALMIE NATIONAL FOREST, Picture Lake , [48.866217, 121.676533], 1255m, 8.vii.2010 , CNCD 60058 , A. Young ( CNC). Price Co.: Pleasant Valley , [48.90667, -122.70333], 21.v.1977, JSS 25097 , T.L. Whitworth ( EMUS) .

Figures

FIGURE 8. Dasysyrphus laticaudus: A: female (CNCD 13875) dorsal habitus; B: female lateral (CNCD 13875) habitus; C: lateral view of male (CNCD 30087) genitalia; D: male (JSS 20763) lateral habitus; E: wing base (JSS 24614). Dorsal and lateral habitus scale bar = 1mm, genitalia and wing scale bar = 500µm.

FIGURE 11. Dasysyrphus nigricornis: A: male (CNCD 13711) dorsal habitus; B: female (CNCD 13568) dorsal habitus; C: male (CNCD 13711) lateral habitus; D: lateral view of male (CNCD 9206) genitalia; E: wing base (CNCD 13725). Dorsal and lateral habitus scale bar = 1mm, genitalia and wing scale bar = 500µm.

FIGURE 13. Dasysyrphus pacificus: A: male (CNCD 35314) dorsal habitus; B: male (CNCD 35314) lateral habitus; C: wing base (CNCD 60058); D: lateral view of male (CNCD 26435) genitalia. Dorsal and lateral habitus scale bar = 1mm, genitalia and wing scale bar = 500µm.

FIGURE 14. Dasysyrphus pauxillus: A: male (JSS 24616) dorsal habitus; B: male (JSS 24616) lateral habitus; C: wing base (CNCD 13830); D: lateral view of male (CNCD 13746) genitalia. Dorsal and lateral habitus scale bar = 1mm, genitalia and wing scale bar = 500µm.

FIGURE 21. Dasysyrphus species range maps (symbols indicate specimen point data). A: D. lotus (squares) and D. nigricornis (circles); B: D. occidualis; C: D. pacificus; D: D. pauxillus (circles) and D. pinastri (squares).