Scatophila mesogramma (Loew)

Zatwarnicki, Tadeusz & Mathis, Wayne N., 2024, Revision of the Nearctic Species of the Shore-Fly Genus Scatophila Becker (Diptera: Ephydridae), Zootaxa 5487 (1), pp. 1-100 : 38-41

8. Scatophila mesogramma (Loew)

Figs. 47 , 60 , 65–71

Scatella mesogramma Loew 1869: 21 .

Scatophila mesogramma .— Sturtevant 1923: 12 [generic combination].— Cole and Lovett 1921: 335 [note, Oregon].— Johnson 1925: 276 [list, Massachusetts, Rhode Island]; 1930: 154 [list, Massachusetts].— Sturtevant and Wheeler 1954: 194 [review].— Wirth 1965: 758 [ Nearctic catalog].— Zatwarnicki 1987: 282–284, 293 [review; checklist].— Zatwarnicki and Mathis 1994: 362 [phylogeny, mesogramma group].— Mathis and Zatwarnicki 1995: 284 [world catalog].

Scatophila infantina Becker 1926: 89 .— Papp 1975b: 126 [key].— Cogan 1984: 170 [Palearctic catalog].— Zatwarnicki 1987: 282 [synonym of Scatella mesogramma Loew ].

Diagnosis.—This species is a member of the mesogramma species group and is distinguished from congeners by the following combination of characters: Body highly variable, from almost entirely and uniformly whitish gray to highly mottled and with substantial brown coloration, especially on mesonotum; moderately small shore flies, body length 1.85–2.40 mm.

Head ( Figs. 65–66 ): Mesofrons uniformly gray to mostly brown; lateroclinate fronto-orbital seta not so far forward, distance between lateroclinate fronto-orbital seta and medial vertical seta only slightly longer than between medial and lateral vertical setae. Face gray and or brown, if brown, then similar to frons and anterior portion of gena, ventral margin of male face in lateral view nearly vertical not distinctly concave; facial setae and setulae small, none prominent, generally oriented ventrally; lower facial seta not oriented laterally or slightly curved dorsally. Gena high, approximately twice height of basal flagellomere, gena-to-eye ratio 0.42–0.50.

Thorax ( Figs. 47 , 60 ): Coloration of mesonotum ( Fig. 60 ) highly variable, usually mostly gray with brown pattern mostly medially and/or on posterior portion, laterad of acrostichal tracks and especially laterad of dorsocentral track and over postpronotum, if on medial area, becoming wider posteriorly; scutellar disc whitish or partially to mostly dark but often with basal and sometimes with apical areas gray. Acrostichal setae irregular in size, arranged in 2 regular rows; dorsocentral setae 2, anterior seta sutural or just postsutural, presutural dorsocentral setae lacking. Wing ( Fig. 47 ) variable, moderately dark with evident pattern or pale spots although these not prominent or wing mostly pale, whitish, a spotted pattern scarcely evident; cell r 1 lacking white spots; large, quadrate white spot of cell r 3 lacking a dark center; costal vein ratio 0.21–0.25; M 1 vein ratio 0.69–0.77. Knob of halter yellow. Midfemur of ♂ bearing row of spine-like setae posteroventrally on apical half; tarsi mostly black, with some faint reddish coloration on basitarsus.

Abdomen ( Figs. 67–70 ): Tergites gray, rather heavily microtomentose, appearing dull. Male terminalia ( Figs. 67–70 ): Epandrium in posterior view ( Fig. 67 ) with dorsal margin rounded, lateral margins shallowly and evenly curved and ventral margin distinctly emarginate, emargination shallowly and broadly V-shaped, epandrial width in posterior view ( Fig. 67 ) less than height; height of cercal opening ( Fig. 67 ) about 1/3 overall epandrial height, epandrial setulae of equal size, sparse medially and along lateral margins, clustered along ventral margin, where some size variation is evident, epandrium in lateral view ( Fig. 68 ) with dorsal 1/3 narrow, strap-like, dorsal margin truncate, ventral 2/3 rectangular, ventral margin rounded, anterior margin with shallow, broad point at ventral 1/3; cerci in posterior view ( Fig. 67 ) lunate, acutely pointed dorsally, in lateral view ( Fig. 68 ) semihemispherical; aedeagus in lateral view ( Fig. 70 ) more or less rectangular, moderately rounded basally, height of base slightly higher than 2/3 aedeagal length, posterior margin mostly truncate but posteroventral corner produced to a point, posterodorsal corner rounded, dorsal margin moderately excavated on basal half, cavity shallowly and broadly U-shaped, in ventral view ( Fig. 69 ) irregularly ovate, lateral margins shallowly angulate, posterior margin shallowly and broadly rounded; ventral aedeagal process shallowly C-shaped; phallapodeme in lateral view ( Fig. 70 ) elongate, narrow, rod-like but tapered to point at ventral apex, shallowly curved, not distinctly elbowed, in ventral view ( Fig. 69 ) with T-shaped crossbar, crossbar short, width less than width of medial process at its apex, medial process gradually enlarged toward posterior apex, posterior apex slightly flared laterally, shallow bifurcate; postgonite in lateral view ( Fig. 70 ) irregularly V-shaped, dorsal arm subrectangular, length about twice width, posterior extension triangular, very narrow, with ventral arm narrow, elongate, tapered, posterior apex sharp with nipple-like apex, bearing setulae on dorsal and ventral surfaces, dorsal arm more or less rectangular, anterior apex distinctly emarginate, in ventral view with posterior apex shallowly bifurcate, in ventral view basal half somewhat rectangular, base emarginate, emargination irregular, apical half tapered to apical point, latter bearing numerous setulae; neohypandrium in lateral view ( Fig. 70 ) elongate, narrow, shallowly curved.

Type Material.— The holotype male of Scatophila mesogramma is labeled “364/ R. I. [= Rhode Island: Newport Co., Newport. United States]/Loew Coll./ mesogramma Lw. / Type 1118” preserved under no. 11176 in MCZ .

The holotype female of Scatophila infantina is labeled “Potsdam 24. 5. 1907 /57 [blue]/Type [pink]/ infantina Bck det. Oldenberg/ Scatophila infantina Beck. /label illegible [probably comparison with S. variegata signata ]/Coll. Oldenberg/ Holotypus [red]/1972 [on the reverse side]” and is preserved in SDEI.

Other Specimens Examined.— UNITED STATES. ALASKA. Aleutians East (Census Area): Wosnesenski Island (55°13'N, 161°22.1'W; back beach; pan trap), 11 Jul 2009, D. S. Sikes (2♂, 16♀; UAF). Anchorage: Mirror Lake (61°25.7'N, 149°24.9'W), 5 Aug 2002, D. and W. N. Mathis (1♂; USNM). Fairbanks North Star: Chena Lake Recreation Area (64°47.6'N, 147°11.4'W), 10 Aug 2003, D. and W. N. Mathis (4♂; USNM); Fairbanks, Lake Ballaine (64°52.2'N, 147°49.5'W; 160 m), 2 Aug 2011, D. and W. N. Mathis (3♂, 1♀; USNM); Fairbanks, Creamer’s Field (64°51.7'N, 147°44.3'W; 160 m), 3 Aug 2011, D. and W. N. Mathis (1♂, 2♀; USNM). Kenai Peninsula: Deep Creek (60°02'N, 151°42'W; gravel to cobble beach), 2 Aug 2002, D. and W. N. Mathis (1♂, 2♀; USNM); Homer (59°38.8'N, 151°31.5'W), 2 Aug 2002, D. and W. N. Mathis (3♂; USNM); Homer (59°38.3'N, 151°30'W; tidal flat), 4 Jul 2006, D. and W. N. Mathis (1♀; USNM); Kenai Lake (60°20.5'N, 149°22.2'W; Primrose Campground), 31 Jul 2003, D. and W. N. Mathis (3♂; USNM); Kenai Fjord National Park, Exit Glacier (60°11.3'N, 149°37.6'W), 30 Jul 2002, D. and W. N. Mathis (5♂, 6♀; USNM); Ninilchik (60°03'N, 151°40.2'W; beach), 2 Jul 2006, D. and W. N. Mathis (17♂, 5♀; USNM); Seward (21 km N; 60°17.2'N, 149°20.5'W; Snow River ), 31 Jul 2002, D. and W. N. Mathis (17♂, 1♀; USNM); Skilak Lake (60°26.3'N, 150°19.4'W), 3 Aug 2002, D. and W. N. Mathis (1♀; USNM). Lake and Peninsula: Savonoski, Naknek Lake (58°32'N, 155°19'W), 26 Jul 1919, A. Basinger (6♀; CAS). Matanuska-Susitna: Eklutna (Knik Arm; 61°28.2'N, 149°21.4'W), 7 Aug 2002, D. and W. N. Mathis (2♂; USNM); Hatcher Pass (61°45'N, 149°13.9'W), 6 Aug 2002, D. and W. N. Mathis (1♂, 1♀; USNM); Lake Lucille (61°34.2'N, 149°28.6'W; 100 m), 25 Jul 2011, D. and W. N. Mathis (1♂; USNM); Palmer ( Matanuska River ; 61°36.5'N, 149°04.1'W), 5 Aug 2002, D. and W. N. Mathis (2♂; USNM); Willow Creek (61°46.1'N, 150°04.2'W; 50 m), 26 Jul 2011, D. and W.N. Mathis (2♂, 1♀; USNM). Nome ( Census Area ): Glacier Creek Road (64°34.9'N, 165°23.2'W), 30 Jul–1 Aug 2012, D. and W. N. Mathis (1♂, 2♀; USNM); Golovin (64°32.6'N, 163°01.8'W), 19 Aug 1929 (1♀; USNM); Nome River (64°29.2'N, 165°17.6'W), 30 Jul 2012, D. and W. N. Mathis (1♀; USNM); Pilgrim Hot Springs (65°05.6'N, 164°55.6'W), 3 Aug 2012, D. and W. N. Mathis (5♂, 5♀; USNM); Safety Sound (35.4 km E Nome; 64°28.4'N, 165°44.7'W), 30 Jul 2012, D. and W. N. Mathis (5♂, 8♀; USNM); Snake River (11 km NW Nome; 64°33.9'N, 165°30.6'W), 2 Aug 2012, D. and W. N. Mathis (13♂, 10♀; USNM); Teller (65°15.4'N, 166°21.1'W), 2 Aug 2012, D. and W. N. Mathis 3♂, 5♀; USNM). North Slope : Cape Thompson, Chariot Site (68°06.3'N, 165°44.6'W), Aug 1960, L. Throckmorton (1♂, 4♀; USNM). Valdez-Cordova (Census Area): Glennallen (32 km W; 62°05.9'N, 146°05.4'W; 665 m), 27 Jul–7 Aug 2011, D. and W. N. Mathis (2♂, 1♀; USNM); Gulkana River (19.3 km N Glennallen; 62°16.1'N, 145°23.1'W), 9 Jul–7 Aug 2006, 2011, D. and W. N. Mathis (25♂, 4♀; USNM); Klutina River (mile 101; 61°57.2'N, 145°19.3'W; 315 m), 7 Aug 2012, D. and W. N. Mathis (1♂; USNM). Yukon-Koyukuk (Census Area): Yukon River at Dalton Highway (65°52.8'N, 149°43.2'W; 110 m), 4 Aug 2011, D. and W. N. Mathis (1♀; USNM) .

DELAWARE. Sussex: Rehoboth (38°43.2'N, 75°04.6'W), 25 Jun 1939, A. L. Melander (4♂, 6♀; USNM) .

MARYLAND. Baltimore: Hart-Miller Island (39°15.1'N, 76°22.4'W), 31 May 1987, W. E. Steiner, J. M. Swearingen (5♀; USNM). Calvert: Chesapeake Beach (38°41.2'N, 76°32.1'W), 24–31 May 1931, 1933, J. R . Malloch (2♂, 1♀; ANSP, USNM) .

MASSACHUSETTS. Dukes: Martha’s Vinyard, Oak Bluffs (41°27.3'N, 70°33.4'W), 13 Jun 1917, C. W. Johnson (1♀; ANSP) .

NEW JERSEY. Cape May: Wildwood (38°59.5'N, 74°48.9'W), 18 Jul 1908 (1♀; ANSP) .

NORTH DAKOTA. Bowman: Bowman-Haley Reservation (45°59.5'N, 100°45'W), 19 Jun 2008, D. and W. N. Mathis (1♀; USNM) .

OREGON. Coos: Bandon (Oregon Islands N.W. Refuge; 43°06.8'N, 124°26.1'W; beach), 1 Nov 2007, D. and W. N. Mathis (1♀; USNM) ; Seven Devils State Recreation Site (43°14.2'N, 124°23.4'W; beach), 30 Jul 2005, D. and W. N. Mathis (11♂, 9♀; USNM) . Lane: Heceta Head (44°08.1'N, 124°07.4'W; beach), 1 Aug 2005, D. and W. N. Mathis (1♀; USNM) .

SOUTH DAKOTA. Mellette: Little White River (43°36.1'N, 103°15.4'W; 840 m), 4 Jun 1969, W. W. Wirth (2♀; USNM) .

VIRGINIA. Accomack: Assateague Island, Toms Cove (37°53.1'N, 75°20.7'W), 16 Jun 2007, D. and W. N. Mathis (10♂, 11♀; USNM). Northampton: Oyster (37°17.2'N, 75°55.4'W), 14 Jun 2007, D. and W. N. Mathis (1♂; USNM) .

WASHINGTON. Pacific: Long Beach (46°20.8'N, 124°03.8'W; beach), 30 Mar 2006, D. Mathis (9♂, 1♀; USNM); Ocean Park (46°29.5'N, 124°03.4'W; beach), 30 Mar 2006, D. Mathis (1♂; USNM) .

Type Locality.— United States. Rhode Island. Newport: Newport (41°29.4'N, 71°18.8'W) .

Distribution ( Fig. 71 ).— Nearctic : Canada (Newfoundland and Labrador, Nova Scotia), United States (Alaska, Delaware, Maryland, Massachusetts, New Jersey, North Dakota, Oregon, Rhode Island, South Dakota, Virginia, Washington). Palearctic: Belgium, Denmark, Germany, Netherlands, Poland, Sweden.

Remarks.—This species, which is placed in the mesogramma group, is found on marine beaches of both the Atlantic and Pacific coasts at more northern latitudes. This may indicate a feeding preference for algae that are associated with saline condition on marine beaches.

Figures

FIGURE 71. Distribution map of Scatophila mesogramma (Loew) (circles), and S. pulchra Sturtevant & Wheeler (squares) in Nearctic Region.

FIGURES 45–47. Head, thorax and wing of Scatophila. 45. S. adamsi Cresson, head and thorax, dorsal view. 46–47. Wing, dorsal view. 46. S. iowana Wheeler. 47. S. mesogramma (Loew). Scale bar = 0.2 mm.

FIGURES 56–60. Head and thorax of Scatophila. 56–57. Head of S. iowana Wheeler. 56. Latero-oblique view. 57. Lateral view. 58–60. Head and thorax, dorsal view. 58. S. hesperia Sturtevant & Wheeler. 59. S. iowana Wheeler. 60. S. mesogramma (Loew). Scale bar = 0.2 mm.

FIGURES 65–66. Head of Scatophila mesogramma (Loew). 65. Latero-oblique view. 66. Lateral view. Scale bar = 0.2 mm.

FIGURES 67–70. Male terminalia of Scatophila mesogramma (Loew). 67. Epandrium and cerci, posterior view. 68. Same, lateral view. 69. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 70. Same, lateral view. Scale bar = 0.1 mm.