Scatophila arenaria 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 : 65-68

16. Scatophila arenaria Cresson

Figs. 139–145 , 148

Scatophila arenaria Cresson 1935: 372 .— Sturtevant and Wheeler 1954: 187 [review].— Deonier 1964: 109 [key; Iowa]; 1965: 498 [natural history].— Wirth 1965: 758 [ Nearctic catalog].— Zatwarnicki 1987: 291 [checklist].— Zatwarnicki and Mathis 1994: 365 [phylogeny, quadriguttata group].— Mathis and Zatwarnicki 1995: 281 [world catalog].

Diagnosis.—This species is distinguished from congeners by the following combination of characters: Generally, body grayish white to gray with some brown highlights. Minute to small shore flies, body length to 1.65–2.00 mm.

Head ( Figs. 140–141 ): Mesofrons gray with ocellar triangle faintly outlined in brown. Face faintly yellow gray, face of ♂ shallowly projected, medial area slightly flattened or shallowly concave dorsally, with slightly longer setae at lateral margins of facial depression. Gena-to-eye ratio 0.32–0.33.

Thorax ( Figs. 139 , 145 ): Mesonotum ( Fig. 145 ) mostly gray with some brown longitudinal marks along setal tracks; scutellar disc gray, the gray area largely narrowly triangular, apical scutellar setae longer than basal pair. Wing ( Fig. 139 ) relatively dark with evident spotting pattern; costal vein ratio 0.29–0.31; M 1 vein ratio 0.67–0.71; knob of halter yellow. Legs generally dark colored; femora and tibiae invested with gray microtomentum; male midfemur lacking row of spine-like setulae along posteroventral margin; tarsi blackish.

Abdomen ( Figs. 142–144 ): Tergites mostly gray with some faint bluish or greenish tint. Male terminalia ( Figs. 142–144 ): Epandrium in posterior view ( Fig. 142 ) generally oval except for truncate and somewhat narrowed ventral margin, width nearly 0.80 height, lateral margins shallowly and angularly curved, width of ventral margin slightly greater than width of cercal opening; dorsal margin of epandrium in posterior view ( Fig. 142 ) somewhat narrowly rounded; epandrial setae about equal in length, sparser medially, more abundant along ventral margin; height of cercal opening about 0.40 epandrial height; cerci in posterior view ( Fig. 142 ) lunate, slightly narrower dorsally; aedeagus in lateral view ( Fig. 144 ) narrowly rounded basally, becoming narrower distally, posterior apex narrowly truncate except for digitiform, short process extended from posterodorsal angle, dorsal margin strongly excavated, cavity nearly twice as long as wide, in ventral view ( Fig. 143 ) oval; ventral aedeagal process sinuous; phallapodeme in lateral view ( Fig. 144 ) elongate, narrow, distinctly angulate, length of dorsal portion (toward base of aedeagus) conspicuously shorter than ventral portion, rod-like, ventral portion elongate, mostly parallel sided but slightly tapered to blunt apex, in ventral view ( Fig. 143 ) T-shaped, basal crossbar about half length of medial process, crossbar distinctly tapered; postgonite in lateral view ( Fig. 144 ) deeply V-shaped, with dorsal, wider arm or extension somewhat rectangular but with nipple-like apex, bearing setulae, ventral arm in lateral view narrowed, parallel sided, elongate, in ventral view ( Fig. 143 ) with posterior extensions narrowly rod-like; neohypandrium in lateral view ( Fig. 144 ) narrow, angulate at right angle, elongate, extended, posterior portion longer than anterior portion.

Type Material.—The holotype male of Scatophila arenaria Cresson is labeled “[ United States.] Ilwaco, Wash[ington][,] Beach.Jul.’[19]17[,] A.L.Melander/Holo-TYPE Scatophila ARENARIA E. T. Cresson Jr [magenta; species name handwritten]. The holotype is double mounted (minute nadel in rectangular card block), is in good condition, and is deposited in the ANSP.

Other Specimens Examined.— UNITED STATES. ARIZONA. Cochise: Fairbank (31°43.4'N, 110°11.3'W), 13 Jun 1951 , A. H. Sturtevant (1♂, 1♀; USNM) .

CALIFORNIA. Humbolt: Trinidad (41°03.5′N, 124°08.6′W) , 18 Sep 1934, A. L Melander (1♀; USNM). Mono : Crowley Lake (37°34.4′N, 118°47.5′W) , 10 May 1950, A. H. Sturtevant (1♂; USNM) .

IOWA. Boone: Ledges State Park (E bank of Des Moines River ; 41°59.5'N, 93°53.5'W), D. L. Deonier (1♀; USNM) .

NEBRASKA. Cherry: Snake River (42°46.8′N, 100°47.7′W), 2 Jun 1969, W. W. Wirth (3♂, 3♀; USNM) .

NEW MEXICO. Catron: Gila River (33°13.6'N, 106°15.1'W; 1750 m), 15 Aug 2007, D. and W. N. Mathis (3♂; USNM). Grant : Mimbres River (NM Hwy. 61 & Royal John Mine Road; 32°43.8'N, 107°52'W; 1665 m), 1 Aug 2008, D. and W. N. Mathis (10♂; USNM) .

OREGON. Coos: Bandon (43°07.1′N, 124°24.5′W), 1 Nov 2007, D. and W. N. Mathis (1♂; USNM) ; Lakeside (43°34.4′N, 124°10.3′W), 4 Aug 1965, K. E. Goeden (7♂, 10♀; USNM) ; 7 Devils State Park (43°14.2′N, 124°23.4′W), 30 Jul 2005, D. and W. N. Mathis (1♂; USNM) . Curry: Ophir (42°33.8′N, 124°23′W), 28 Jul 1951, A. H. Sturtevant (16♂, 16♀, USNM) ; Port Orford (42°44.6′N, 124°29.8′W), 24 Oct 2007, D. and W. N. Mathis (3♂; USNM) . Hood River: Mt. Hood (45°32.2′N, 121°34.2′W), 25 Jun 1934, A. L. Melander (1♂; USNM) . Jackson: Prospect (42°45.1′N, 122°29.3′W), 20 Aug 1951, A. H. Sturtevant (1♀; USNM) . Umatilla: Cold Springs (45°52.7′N, 119°09.9′W), 21 Jun 1954, J. J. Davis (1♂; USNM) .

WASHINGTON. Asotin: Snake River at Grande Ronde River (46°04.8′N, 116°58.8′W), 6 Jul 1925, A. L. Melander (3♀; USNM) . Franklin: Basin City (30.5 km N; 46°37'N, 119°09'W), 19 May 1973; W. N. Mathis (1♂, 1♀; USNM) . Kittitas: Vantage ( Columbia River ; 46°56.5'N, 119°59.1'W), 5 Aug 1951, A. H. Sturtevant (18♂, 18♀; USNM) . Pacific: Ilwaco (46°18.5'N, 124°02.6'W), Jul 1917, A. L. Melander (12♂, 29♀; USNM) ; Ocean Park (46°29.4'N, 124°02.5'W), 18 Jul 1959, M. T. James (5♂, 3♀; USNM) .

WYOMING. Teton: Yellowstone National Park, Bath Lake (44°32.5'N, 110°47.5'W), 18 Jul 1923, A. L. Melander

(1♂; USNM). Type Locality.— United States. Washington. Pacific: Ilwaco (46°18.5'N, 124°02.6'W). Distribution ( Fig. 148 ).— Nearctic : United States (Arizona, California, Iowa, Minnesota, Nebraska, New

Mexico, Oregon, Washington, Wyoming). Natural History.— Deonier (1965) reported this species from a sand shore habitat in Iowa. Remarks.—This species is placed in the quadriguttata group.

Figures

FIGURE 148. Distribution map of Scatophila arenaria Cresson.

FIGURES 137–141. Head, thorax and wing of Scatophila. 137. S. variofacialis Sturtevant & Wheeler, head and thorax, dorsal view. 138–139. Wing, dorsal view 138. S. variofacialis Sturtevant & Wheeler. 139. S. arenaria Cresson. 140. Head of S. arenaria Cresson, latero-oblique view. 141. Same, lateral view. Scale bar = 0.2 mm.

FIGURES 142–144. Male terminalia of Scatophila arenaria Cresson. 142. Epandrium and cerci, posterior view. 143. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 144. Same, lateral view. Scale bar = 0.1 mm.

FIGURES 145–147. Head, thorax and wing of Scatophila. 145. Scatophila arenaria Cresson, head and thorax, dorsal view. 146–147. Wing, dorsal view. 146. S. bipiliaris Sturtevant & Wheeler. 147. S. bisignata Cresson. Scale bar = 0.2 mm.