Scatophila bisignata 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 : 71-73

18. Scatophila bisignata Cresson

Figs. 147 , 160–167

Scatophila bisignata Cresson 1935: 370 .— Sturtevant and Wheeler 1954: 188 [review].— 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: Pattern of wing spots, bicolored coloration, and shape of structures of the male terminalia. Body mostly gray with many, contrasted brown spots and elongate spots; small to moderately small shore flies, body length 1.90–2.20 mm.

Head ( Figs. 160–163 ): Mesofrons tan but unevenly colored, with whitish area anteromedially, some darker areas towards lateral setae; lateroclinate fronto-orbital seta inserted at about double distance away from medial vertical setae and distance between vertical setae. Face gray with brown spots variable but often at apex of facial hump and at sides of facial hump; face of ♂ convex, arched. Gena relatively short, gena-to-eye ratio 0.22–0.25. Femora and tibiae dark colored with gray microtomentum; tarsi yellowish basally, apical 2–3 darker, blackish.

Thorax ( Figs. 147 , 165 ): Mesonotum ( Fig. 175 ) with distinct, presutural dorsocentral setae, other setae well developed; scutellar disc brown with gray, lateral margin and a medial small gray triangular area at margin with mesonotum. Wing ( Fig. 147 ) brown with conspicuous white spots, including 2–3 prominent spots in cell r 1; veins R 2+3 and R 4+5 sinuous around white spots; costal vein ratio 0.24–0.27; M 1 vein ratio 0.77–0.81. Knob of halter yellow. Legs with considerable pale coloration; femora dark with gray microtomentum; male midfemur lacking row of spine-like setulae along posteroventral margin; tibiae yellowish, darker dorsally; basal 2 tarsomeres yellow, apical 3 becoming darker, blackish.

Abdomen ( Figs. 164–166 ): Tergites mottled, mostly gray with considerable brown patches. Male terminalia ( Figs. 164–166 ): Epandrium in posterior view ( Fig. 164 ) generally irregularly rectangular, height almost twice width, ventral margin somewhat truncate ( Fig. 164 ), shallowly pointed medially and with extended posterolateral, angulate corners; ventral margin, about equal to height of cercal opening; dorsal margin of epandrium in posterior view ( Fig. 164 ) somewhat broadly and shallowly rounded, lateral margins widest at midheight, thereafter narrowed posterior to broad, parallel-sided extension; epandrial setulae about equal in length, lateral setulae slightly longer than medial setulae, more abundant along ventral margin; height of cercal opening slightly less than 1/3 epandrial height; cerci in posterior view ( Fig. 164 ) robustly lunate, narrowed dorsally; aedeagus in lateral view ( Fig. 166 ) robustly rounded basally, forming irregular rectangle, posterior portion broadly and shallowly rounded and with short pointed, digitiform process at posterodorsal angle, in ventral view ( Fig. 165 ) narrowly ovate, wider anteriorly than posteriorly, tapered toward posterior apex; ventral aedeagal process conspicuously curved; phallapodeme in lateral view ( Fig. 166 ) elongate, narrow, angulate at dorsal third, length of dorsal portion (toward base of aedeagus) about ¾ length of ventral portion, ventral portion elongate and linear, tapered to narrowed apex, in ventral view ( Fig. 165 ) T-shaped, basal crossbar about 1/3 length of medial process, crossbar distinctly tapered; postgonite in lateral view ( Fig. 166 ) V-shaped, with dorsal extension somewhat narrowly rectangular but with nipple-like process at posterodorsal angle, bearing setulae, ventral extension narrow, parallel sided, shallowly curved, elongate, in ventral view ( Fig. 165 ) with posterior extensions narrowly rod-like and with nipple-like apex; neohypandrium in lateral view ( Fig. 166 ) narrow, sinuous, elongate, parallel-sided along length.

Type Material.— The holotype male of Scatophila bisignata Cresson is labeled “Kennewick W[ashingto]n[,] 7 June ‘[19]16[,] A.L.Melander / ♂ [handwritten]/ TYPE No. 6522[,] Scatophila BISIGNATA E T Cresson, Jr. [dark pink; species name and number handwritten].” The holotype is double mounted (minute nadel in rectangular card block), is in poor condition (the head is missing), and is deposited in the ANSP (6522).

Other Specimens Examined.— UNITED STATES. CALIFORNIA. Inyo : Lone Pine (36°36.4'N, 118°03.8'W), 28 Jul 1940, D. E. Hardy (1♂; USNM) . Nevada: Hobart Mills (2.5 km NW; 39°40'N, 120°18'W), 20 Jun 1974, W. N. Mathis (1♀; USNM) .

UTAH. Garfield: Deer Creek (37°51.2'N, 111°21.1'W; 1762 m), 21 May 2001, D. and W. N. Mathis (1♀; USNM) .

WASHINGTON. Grant : O’Sullivan Dam (46°59'N, 119°17.4'W), 23 May 1954, M. T . James (1♂; USNM). Okanogan: Omak (48°34'N, 119°45'W), 19 May 1916, A. L. Melander (1♂; USNM). Whitman: Uniontown (46°32.2'N, 117°05.3'W), 26 Jun 1932, J. M. Aldrich (1♀; USNM) .

Type Locality.— United States. Washington. Benton: Kennewick (46°12.5'N, 119°07.2'W) .

Distribution ( Fig. 167 ).— Nearctic : United States (California, Utah, Washington).

Remarks.—This species is placed in the quadriguttata group.

Figures

FIGURE 167. Distribution map of Scatophila bisignata Cresson (circles), and S. picta Sturtevant & Wheeler (square).

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.

FIGURES 160–163. Head of Scatophila bisignata Cresson. 160. Male, latero-oblique view. 161. Male, lateral view. 162. Female, latero-oblique view. 163. Female, lateral view. Scale bar = 0.2 mm.

FIGURES 164–166. Male terminalia of Scatophila bisignata Cresson. 164. Epandrium and cerci, posterior view. 165. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 166. Same, lateral view. Scale bar = 0.1 mm.

FIGURES 175–179. Head and thorax of Scatophila. 175–177. Head and thorax, dorsal view. 175. Scatophila bisignata Cresson. 176. S. conifera Sturtevant & Wheeler. 177. S. cribrata (Stenhammar). 178–179. Head of Scatophila cribrata (Stenhammar). 178. Latero-oblique view. 179. Lateral view. Scale bar = 0.2 mm.