Scatophila exilis Cresson

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 : 15-20

2. Scatophila exilis Cresson

Figs. 9–10 , 14–15 , 18–21

Scatophila exilis Cresson 1935: 366 .— Sturtevant and Wheeler 1954: 192 [review].— Wirth 1965: 758 [ Nearctic catalog].— Zatwarnicki 1987: 292 [checklist].— Zatwarnicki and Mathis 1994: 362 [phylogeny, contaminata group].— Mathis and Zatwarnicki 1995: 283 [world catalog].

Description.—This species, which is a member of the contaminata group, is distinguished from congeners by the following combination of characters: This is a generally small, dark-colored species, blackish brown with some small gray areas; small shore flies, body length to 1.40–1.55 mm.

Head ( Figs. 14–15 ): Mesofrons generally dark brown with some gray spots along anterior margin; face of ♂ and female about equal, projected slightly but not concave or flattened; face covered by metallic microtomentum; gena short, gena-to-eye ratio 0.16–0.20.

Thorax ( Figs. 9–10 ): Mesonotum ( Fig. 10 ) mostly dark brown but with some, small gray areas; scutellum dark brown, some specimens with apex gray; a prescutellar pair of acrostichal setae usually well developed, subequal to length of ocellar setae. Wing ( Fig. 9 ) with conspicuous spots; costal vein ratio 025–0.29; M 1 vein ratio 0.61–0.64; knob of halter darkened, faintly whitish brown. Legs mostly dark colored, femora with some light investment of gray microtomentum; male midfemur lacking row of spine-like setulae along posteroventral margin; tarsi black.

Abdomen: Tergites blackish. Male terminalia ( Figs. 18–20 ): Epandrium in posterior view ( Fig. 18 ) nearly as wide as high, dorsal margin rounded, lateral margins slightly wider at midheight, ventral margin broadly truncate, width of truncate ventral margin greater than width of cercal opening; cercal opening comparatively large, width almost equal to height, height of cercal opening equal to 0.70 epandrial height; cerci in posterior view ( Fig. 18 ) large, hemispherical; aedeagus in lateral view ( Fig. 20 ) comparatively short, length only slightly longer than height, moderately rounded basally, posterior margin narrowed to a triangular point, dorsal margin shallowly excavated, cavity slightly longer than width of opening, in ventral view ( Fig. 19 ) ovate, lateral margins shallowly curved; ventral aedeagal process lacking; phallapodeme in lateral view ( Fig. 20 ) elongate, narrow, parallel sided, distinctly elbowed, apical process shorter than ventral process, in ventral view ( Fig. 19 ) with T-shaped crossbar, nearly straight, lateral extensions parallel sided, medial process nearly parallel sided, only slightly longer than crossbar; postgonite in lateral view ( Fig. 20 ) generally V-shaped, dorsal arm or extension irregularly rectangular with posteroventral corner slightly produced, posterior ¼ narrowed, forming a thumb-like process that bears a short nipple-like point, apical process bearing setulae, ventral arm narrow, elongate, almost parallel sided, in ventral view ( Fig. 19 ) with posterior processes generally narrow, thumb-like, apices extended slightly laterally; neohypandrium in lateral view ( Fig. 20 ) elongated, narrow, shallowly sinuous.

Type Material.—The holotype male of Scatophila exilis Cresson is labeled “Boulder Co. [“Co.” crossed out by two crosshatch marks] Colo./ W. E. Watkins Coll. [handwritten]/Type No. 51297 U. S. N. M. [number handwritten; red]/TYPE No. 51297 Scatophila EXILIS E. T. Cresson, Jr. [number and species name handwritten; red].” The holotype is double mounted (glued to a narrow triangle), is in excellent condition, and is deposited in the USNM (51297).

Other Specimens Examined.— CANADA. BRITISH COLUMBIA. Kamloops (50°40'N, 129°19.1’W: alkali lake), 2 Jul 1968, W. W. Wirth (1♂, 2♀; USNM) .

MANITOBA. Treesbank (49°38.1'N, 99°36.3'W), 6 May 1916 (1♂; USNM) .

SASKATCHEWAN. Saskatoon (52°07'N, 106°38.6'W), 28 Jul 1955, W. W. Wirth (1♀; USNM) .

MEXICO. BAJA CALIFORNIA: Rosarito (32°21.9'N, 117°02.8'W), 22 Mar 1950, G. Lindsley (2♂; USNM). Misión de San Miguel (32°05.6'N, 116°51.1'W), 22 Mar 1950, G. Lindsley (1♂; USNM) .

UNITED STATES. ARIZONA. Cochise: Ramsey Canyon (31°26.8'N, 110°18.4'W), 15 Jun 1951, A. H. Sturtevant (1♂; USNM) .

CALIFORNIA. Los Angeles: Claremont (34°07.9'N, 117°44.4'W), 3 Mar 1950, A. H. Sturtevant (1♂; USNM) ; Dark Canyon (34°08.6'N, 118°20.4'W), 16 Jul 1951, A. H. Sturtevant (1♀; USNM) ; Pasadena (34°09.4'N, 118°07.9'W), 7 Mar–24 Apr 1950, A. H. Sturtevant (3♂, 2♀; USNM) ; Rio Hondo (33°55.9'N, 118°10.5'W), 13 Apr 1950, A. H. Sturtevant (1♂; USNM) . Rosemead (34°04'N, 118°05'W), 17 Mar 1950, G. Lindsley (1♂; USNM) . Orange: Corona del Mar (33°35.9'N, 117°52.4'W), 25 Mar 1946, A. L. Melander (1♀; USNM) . Riverside: Lake Hemet (33°39.7'N, 116°42.4'W), 30 Jun 1965, R. E. Orth (1♂; USNM) ; Temecula (33°29.2'N, 117°08.6'W), 25 May 1965, T. W. Fisher (1♀; USNM) ; Tucolota Creek (9 km W Sage River; 33°32.5'N, 116°42.4'W), 1 Jul 1963, E. I Schlinger (1♂; USNM) . San Bernardino: Helendale (34°44.6'N, 117°19.5'W), 18 May 1955, W. R. Richards (1♂; USNM) . San Diego: Jacumba Springs (32°37'N, 116°11.3'W), 28 Jun 1917, J. M Aldrich (1♂; USNM) . San Francisco: San Francisco (37°47.3'N, 122°29.7'W), 1 Aug 1915, A. L. Melander (1♀; USNM) . Santa Barbara : Montecito (34°26.2'N, 119°37.9'W; glass house), 28 Mar 1933 (1♂, 2♀; USNM) . Yolo: Davis (38°32.7'N, 121°44.1'W), 5 May 1953, J. C. Hall (1♀; USNM) .

COLORADO. Boulder: Boulder (40°0.9'N, 105°16.2'W), W. E. Watkins (3♀; USNM) .

NEVADA. Lincoln: Crystal Springs (37°31.9'N, 115°14'W), 21 Jun 1953, A. B. Gurney (1♀; USNM) .

NEW MEXICO. Eddy: Black River (near Rattlesnake Springs; 32°05.2'N, 104°28.3'W; 1110 m), 11 Aug 2007, D. and W. N. Mathis (1♀; USNM). Taos: Rio Grande (36°24.4'N, 105°34.4'W), 6 Jun 1953, W. W. Wirth (1♀; USNM) .

NORTH DAKOTA. 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) . Burke: Powers Lake (48°33.7'N, 102°38.8'W), 8 Jun 1969, W. W. Wirth (1♀; USNM) . Mountrail: White Lake (46°28.5'N, 103°13.1'W), 8 Jun 1969, W. W. Wirth (1♀; USNM) .

OKLAHOMA. Oklahoma: Oklahoma City (35°28.9'N, 97°30.5'W), 21 Mar 1944 (1♀; USNM) .

OREGON. Baker: Goose Creek (35 km E Baker City; 44°49.2'N, 117°27.79'W; 825 m), 7 Jun 2006, D. and W. N. Mathis (1♂, 1♀; USNM) . Harney : 29 Jun 1958, A. B. Gurney (2♂, 2♀; USNM) ; Page Springs Campground , Blitzen River (42°47'N, 118°51'W; 1300 m), 6 Aug 2005, D. and W. N. Mathis (1♀; USNM) ; Pike Creek (42°34.5'N, 118°31.7'W; 1320 m), 7 Aug 2005, D. and W. N. Mathis (1♀; USNM) ; Steens Mountain , Fish Lake Campground (42°44.3'N, 118°38.7'W; 2250 m), 6 Aug 2005, D. and W. N. Mathis (1♀; USNM) . Klamath : South of Worden (42°02.7'N, 121°51.9'W), 1 Jul 1945, P. W. Oman (1♂; USNM) .

SOUTH DAKOTA. Lawrence: 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) .

TEXAS. Lubbock: Buffalo Spring Lake (33°31.6'N, 101°42.3'W), 27 Apr 1969, J. M. Tenorio (2♀; USNM) .

UTAH. Grand: Thompson Springs (9 km N; 39°02.3'N, 109°43.4'W; 1740 m), 1–16 Aug 2007, 2008, D. and W. N. Mathis (1♂; USNM) . Salt Lake: Butterfield Canyon (40°29.2'N, 112°08.2'W; 1890 m), 14 May 2007, D. and W. N. Mathis (1♂; USNM) . Utah: Thistle (40°0.4'N, 111°29.7'W; 1530 m), 11 May 2007, D. and W. N. Mathis (1♂; USNM) .

WASHINGTON. Adams: Othello (3.2 km W; 46°50'N, 119°14'W), 23 Jul 1992, D. and W. N. Mathis (4♂, 3♀; USNM) . Franklin : Port of Pasco (46°12.6'N, 119°02.9'W; 100 m), 6 Jun 2006, D. and W. N. Mathis (6♂, 3♀; USNM) ; Ringold (NW Pasco: 46°30.4'N, 119°15.3'W), 2–10 Jul 1988, 1998, D. and W. N. Mathis (1♂, 1♀; USNM) . Grant : Crab Creek (4.8 km E Beverly; 46°50'N, 119°52'W), 30 May 2006, D. and W. N. Mathis (2♂, 2♀; USNM) ; O’Sullivan Dam (46°59'N, 119°17.4'W), 23 May 1954, M. T. James (2♀; USNM) ; Soap Lake (47°23.5'N, 119°29.1'W), 30 May 2006, D. and W. N. Mathis (4♂, 2♀; USNM) .

Type Locality.— United States. Colorado. Boulder: Boulder (44°00.9'N, 105°16.2'W) .

Distribution ( Fig. 21 ).— Nearctic : Canada (British Columbia, Manitoba, Saskatchewan), Mexico (Baja California), United States (Arizona, California, Colorado, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington).

Remarks.—This species is placed in the contaminata group. The distribution of this species is primarily in western North America. Sturtevant and Wheeler (1954: 192) noted that a specimen from Oklahoma was labeled “Greenhouse; damaging verbena.”

The despecta Group

Diagnosis.—Face mediolaterally bears upturned seta. Mid-tibiae of males with posteroventral row of spinulae. Epandrium elongate, contracted apically, its distal margin incised medially forming two lateral lobate processes ( Figs. 27 , 34 ); neohypandrium reduced; postgonite elongate; proximal margin of postgonite convex; distal process relatively long (1/3 of total length), tapered and with several dorsal setae; ventral processes fused to each other, but separated from the main part of postgonite; aedeagus without ventral process, in dorsal view ovate in outline, in lateral view proximal portion narrowly tapered and ventral margin semicircular; distal margin of the dorsal aedeagal opening broadly round with a collar directed outward; phallapodeme in lateral view straight, in dorsal view with apex as a broadened triangle ( Figs. 28–29 , 35–36 ).

Nearctic species included in the despecta group are: Scatophila angusta sp. nov., and S. variabilis Cresson.

Figures

FIGURE 21. Distribution map of Scatophila exilis Cresson.

FIGURES 6–10. Head, thorax, and wing of Scatophila. 6. Head of S. contaminata (Stenhammar), latero-oblique view. 7. Same, lateral view. 8–9. Wing, dorsal view. 8. S. contaminata (Stenhammar). 9. S. exilis Cresson. 10. S. exilis Cresson, head and thorax, dorsal view. Scale bar = 0.2 mm.

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 18–20. Male terminalia of Scatophila exilis Cresson. 18. Epandrium and cerci, posterior view. 19. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 20. Same, lateral view. Scale bar = 0.1.

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.

FIGURES 34–36. Male terminalia of Scatophila variabilis Cresson. 34. Epandrium and cerci, posterior view. 35. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 36. Same, lateral view. Scale bar = 0.1 mm.