Scatophila angusta, Zatwarnicki & Mathis USNM, 2024

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 : 20-23

3. Scatophila angusta sp. nov.

Figs. 16–17 , 22–23 , 27–30

Scatophila variabilis of authors, not Cresson 1917: 341 [misidentification in part].— Zatwarnicki 1987: 292 [checklist].— Mathis and Zatwarnicki 1995: 287 [world catalog].

Scatophila despecta of authors, not ( Haliday 1839) [misidentification].— Sturtevant 1923: 11 [taxonomic notes].— Sturtevant and Wheeler 1954: 190–191 [review].— Wirth 1965: 758 [ Nearctic catalog].

Diagnosis.—This species is a member of the despecta species group and is distinguished from congeners by the following combination of characters: Body with tan to brown and usually with some lighter markings, scutellar disc with partially to mostly dark but often with basal and sometimes with apical areas gray; small to moderately small shore flies, body length 1.65–2.10 mm.

Head ( Figs. 16–17 ): Lateroclinate fronto-orbital seta inserted far forward, 2–3X as far from medial vertical as the latter is from the lateral vertical seta. Face gray, face of ♂ normally projected, transversely arched, without medial area shallowly depressed; ventral margin of male face nearly flat, not distinctly emarginate; face bearing porrect to slightly dorsally curved seta lateroventrally. Gena high, height slightly greater than height of basal flagellomere; gena-to-eye ratio 0.34–037.

Thorax ( Fig. 22–23 ): Mesonotum ( Fig. 22 ) mostly brown with some grayish stripes; acrostichal setae irregular in size, arranged in 2 regular rows; dorsocentral setae 2, anterior seta sutural or just postsutural, presutural dorsocentral setae lacking; scutum mostly brown but with extensive pattern of gray areas anterior, laterad of acrostichal tracks and especially laterad of dorsocentral track and over postpronotum; medial area brown, becoming wider posteriorly. Wing ( Fig. 23 ) moderately dark with evident pattern or pale spots although these not prominent; cell r 1 lacking white spots; large, quadrate white spot of cell r 3 lacking a dark center; costal vein ratio 0.20–0.21; M 1 vein ratio 0.50–0.60. Knob of halter yellow. Midfemur of ♂ bearing row of spine-like setae posteroventrally on basal half; tarsi blackish brown to black.

Abdomen: Tergites mostly gray to grayish brown or black, rather heavily microtomentose, rarely subshiny, tergites darker anteriorly and laterally. Male terminalia: ( Figs. 27–29 ): Epandrium in posterior view ( Fig. 27 ) generally oval in shape, almost trapezoidal, with dorsal margin moderately narrowly rounded, dorsal portion of lateral margin sloped laterally, almost straight, ventral portion of lateral margin shallowly sinuous, ventral margin emarginate, width equal to cercal cavity width, ventral ¼ bearing long setulae, especially laterally, otherwise setulae scattered, cercal cavity as wide as high, cercal height about ¼ epandrial height; cerci in posterior view ( Fig. 27 ) semihemispherical, acutely pointed dorsally; aedeagus in lateral view ( Fig. 29 ) more or less irregularly quadrate, broadly rounded ventrally, deeply excavated dorsally, with a crossbar-like process, roundly pointed at posteroventral corner, in ventral view ( Fig. 28 ) obovate, wider basally, anterior margin rounded, thereafter irregularly tapered to posterior, pointed apex; ventral aedeagal process lacking; phallapodeme in lateral view ( Fig. 29 ) elongate, narrow, rod-like, nearly straight, in ventral view ( Fig. 28 ) with a hour-glass shape, constricted medially, both anterior and posterior margins about same width, anterior surface very shallowly emarginate, posterior margin truncate; postgonite in lateral view ( Fig. 29 ) irregularly linear with medial enlargements, posterior extension slightly tapered, apex pointed, midlength anterior, thumb-like process, anterior extension digitiform, in ventral view ( Fig. 28 ) more or less H-shaped, lateral structures narrow, tapered, wider anteriorly, becoming very narrow posteriorly; neohypandrium in lateral view ( Fig. 29 ) elongate, narrow, rod-like nearly straight.

Type Material.— The holotype male of Scatophila angusta new species is labeled “ USA. OR[egon]. Baker: Goose Creek (44°49.2'N, 117°27.79'W; 825 m), 7 Jun 2006, D. & W. N. Mathis / USNM ENT 00250326 [plastic bar code label]/HOLOTYPE ♂ Scatophila angusta Zatwarnicki & Mathis USNM [red].” The holotype is double mounted (minute nadel in block of plastic elastomere), is in excellent condition, and is deposited in the USNM. Twelve paratypes (10♂, 2♀; USNM) bear the same label data as the holotype .

Other Specimens Examined.— UNITED STATES. COLORADO. Dolores: Cahone (9 km N; Dolores River ; 37°38.9'N, 108°44.1'W; 1955 m), 3 Aug 2007, D. and W. N. Mathis (1♂; USNM) .

NORTH DAKOTA. Benson : Leeds (48°17.3'N, 99°26.3'W; alkali lake), 5 Jul 1969, W. W. Wirth (1; USNM) . Bowman: Bowman-Haley Dam and Reservoir (45°59.5'N, 103°15.4'W; 840 m), 19 Jun 2008, D. and W. N. Mathis (1♀; USNM) . Mountrail: Powers Lake (48°33.8'N, 102°38.9'W), 8 Jun 1969, W. W. Wirth (2♂, 3♀; USNM) .

OREGON Tillamook: Cape Kiwanda (45°12.9'N, 123°58.3'W; beach), 3 Aug 2005, D. and W. N. Mathis (1♀; USNM) .

SOUTH DAKOTA. Lawrence: Deadwood (44°21.9'N, 103°43.9'W; 1410 m), 17 Jun 2008, D. and W. N. Mathis (1♀; USNM); Deadwood (3.2 km E; 44°23.1'N, 103°41.2'W; 1440 m), 17 Jun 2008, D. and W. N. Mathis (1♂; USNM) .

UTAH. Salt Lake: Butterfield Canyon (40°29.2'N, 112°08.2'W; 1890 m), 14 May 2007, D. and W. N. Mathis (3♂, 1♀; USNM) . Utah: Goshen Warm Springs (39°56'N, 111°29.7'W;), 4 Aug 1992, D. and W. N. Mathis (1♀; USNM) ; Lake Shore (40°06.9'N, 111°41.8'W; 1370 m), 11 May 2007, D. and W. N. Mathis (1♂; USNM) ; Thistle (40°0.4'N, 111°29.7'W; 1530 m), 11 May 2007, D. and W. N. Mathis (1♂; USNM) .

WASHINGTON. Grays Harbor: Grayland (46°47.9'N, 124°06'W; beach), 29 Oct 2007, D. and W. N. Mathis (1♂; USNM) .

WYOMING. Crook: Alva (near; 44°38.6'N, 104°22.8'W; 1330 m), 20 Jun 2008, D. and W. N. Mathis (3♂, 2♀; USNM) .

Type Locality.— United States. Oregon. Baker: Goose Creek (35 km E Baker City; 44°49.2'N, 117°27.79'W; 825 m) .

Distribution ( Fig. 30 ).— Nearctic : United States (Colorado, North Dakota, Oregon, South Dakota, Utah, Washington, Wyoming).

Etymology.—The species epithet, angusta , is of Latin derivation and means narrow, referring to the narrow bifurcation of the ventral portion of the male epandrium.

Remarks.—This species is placed in the despecta group where it is similar and apparently closely related to S. variabilis . It differs from the latter species primarily by the narrower ventral half of the epandrium, especially the shallower bifurcation along the ventral margin.

Figures

FIGURE 30. Distribution map of Scatophila angusta sp. nov. (circles), S. conifera Sturtevant & Wheeler (triangle), and S. contaminata (Stenhammar) (squares) in Nearctic Region.

FIGURES 14–17. Head of Scatophila. 14. S. exilis Cresson, latero-oblique view. 15. Same, lateral view. 16. Scatophila angusta sp. nov., latero-oblique view. 17. Same, lateral view. Scale bar = 0.2 mm.

FIGURES 22–26. Head, thorax and wing of Scatophila. 22. Scatophila angusta sp. nov., head and thorax, dorsal view. 23. Same, wing, dorsal view. 24. Wing of S. variabilis Cresson, dorsal view. 25–26. Head of Scatophila variabilis Cresson. 25. Male, latero-oblique view. 26. Male, lateral view. Scale bar = 0.2 mm.

FIGURES 27–29. Male terminalia of Scatophila angusta sp. nov. 27. Epandrium and cerci, posterior view. 28. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 29. Same, lateral view. Scale bar = 0.1 mm.