Scatophila hesperia Sturtevant and Wheeler

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 : 32-35

6. Scatophila hesperia Sturtevant and Wheeler

Figs. 33 , 48–55

Scatophila hesperia Sturtevant and Wheeler 1954: 192 .— Wirth 1965: 758 [ Nearctic catalog].— Zatwarnicki 1987: 292 [checklist].— Zatwarnicki and Mathis 1994: 362 [phylogeny, mesogramma group].— Mathis and Zatwarnicki 1995: 283 [world catalog].

Diagnosis.—This species is distinguished from congeners by the following combination of characters: Body with variegated coloration; small shore flies, body length 1.56–1.80 mm.

Head ( Figs. 49–52 ): Mesofrons grayish tan, anterior margin grayer; fronto-orbits slightly darker, brownish gray. Pedicel and sometimes scape yellowish, basal flagellomere gray. Face golden yellow, face of ♂ broadly flattened to shallowly concave medially. Gena moderately wide, height about equal to length of basal flagellomere; gena-to-eye ratio 0.22–0.23.

Thorax ( Figs. 33 , 58 ): Mesonotum ( Fig. 58 ) with variegated and complex pattern of brown, tan, and gray coloration, microtomentose; scutellum with well-defined basal silvery gray triangle, otherwise brown. Wing ( Fig. 33 ) moderately dark, spots conspicuous; quadrate white spot of cell r 3 lacking a prominent dark center; costal vein ratio 0.21–0.23; M 1 vein ratio 0.69–0.77; knob and stem of halter yellow. Coloration of legs variable from pale, mostly yellow, including femora and tibia, or with grayish femora; tarsi yellowish amber, apical tarsomeres darker; male midfemur lacking row of spine-like setulae along posteroventral margin; tarsi blackish.

Abdomen ( Figs. 53–55 ): Tergites of holotype shiny black; female tergites darker toward anterior margin, grayer posteriorly. Male terminalia ( Figs. 53–55 ): Epandrium in posterior view ( Fig. 53 ) generally obovate except for narrow, shallowly angulate, ventral margin, dorsal margin rounded, overall width almost ¾ height, lateral margins shallowly and sinuously curved, with ventral margin about half width of cercal opening; epandrial setae about equal in length, sparser medially and laterally, more abundant along ventral margin; height of cercal opening about 1/2 epandrial height; cerci in posterior view ( Fig. 53 ) hemispherical, medial margin straight; aedeagus in lateral view ( Fig. 55 ) moderately rounded basally, length longer than height, posterior margin mostly truncate but with a short pointed, digitiform process at posterodorsal angle, dorsal margin moderately excavated, cavity slight deeper than wide, in ventral view ( Fig. 54 ) roundly diamond shaped, lateral margins shallowly curved, posterior margin truncate except for medial, pointed process; ventral aedeagal process shallowly C-shaped; ventral aedeagal process shallowly C-shaped; phallapodeme in lateral view ( Fig. 55 ) elongate, narrow, parallel sided, distinctly elbowed, dorsal and ventral extensions about equal in length, in ventral view ( Fig. 54 ) with T-shaped crossbar, crossbar shallowly sinuous, parallel-sided, with secondary helmet-like structure below crossbar, medial process short, length slightly less than length of crossbar, nearly parallel sided; postgonite in lateral view ( Fig. 55 ) generally widely Vshaped, dorsal arm irregularly rectangular with posteroventral corner slightly produced, posterior margin triangular, pointed, bearing short setulae along ventral margin, ventral arm narrowed, elongate, shallowly curved, in ventral view ( Fig. 54 ) Y-shaped, lateral arm and base straight, base almost twice width of lateral arm, notched preapically on lateral margin, setula inserted in notch; neohypandrium in lateral view ( Fig. 55 ) elongated, narrow, bowl-shaped.

Type Material.—The holotype male of Scatophila hesperia Sturtevant and Wheeler is labeled “Pasadena[,] Calif[ornia]. Mar. 20, ‘50 [20 Mar 1950][handwritten]/M.R. Wheeler/ HOLOTYPE Scatophila hesperia Stvt & Whlr [pink]/6682 TYPE [dark pink; number handwritten].” The holotype is double mounted (glued to a paper point), is in good condition, and is deposited in the ANSP (6682).

Other Specimens Examined.— UNITED STATES. ARIZONA. Cochise: Portal ( Southwest Research Station ; 31°53’N; 109°12.5'W; Malaise trap), 5–9 June 1972 , W. W. Wirth (2♂, 1♀; USNM) .

CALIFORNIA. Riverside: Andreas Canyon (33°46.8'N, 116°52.4'W), 12 Nov 1952, A. L. Melander (1♂; USNM) .

COLORADO. Rio Grande: South Fork (37°38.7'N, 106°39.5'W; 2440 m; Malaise trap), 20 Jun 1972, W. W. Wirth (1♂, 1♀; USNM) .

UTAH. Kane: Drip Tank Canyon (37°19.4'N, 111°31.8'W), 29 Mar 2000, D. and W. N. Mathis (1♀; USNM); Sheep Creek ( Gulch Junction Burn Trail ; 37°29.7'N, 112°04'W), 17 May 2001, R . W. Baumann, K. T Huntzinger (2♂; USNM); White House Spring (71 km E Kanab; 37°04.8'N, 111°53.4'W; 1250 m), 19 May 2001, D. and W. N. Mathis (9♂, 6♀; USNM) . Washington: Zion National Park (37°18'N, 112°56'W), 29 Jun 1940, A. L. Melander (1♀; USNM) .

Type Locality.— United States. California. Los Angeles: Pasadena (34°09.4'N, 118°07.9'W) .

Distribution ( Fig. 48 ).— Nearctic : United States (Arizona, California, Colorado, Utah).

Remarks.—This species is placed in the mesogramma group. This species and S. pulchra are the only two species known thus far with yellowish colored faces. Moreover, the extent of yellowish coloration in this species seems to vary considerably. For example, the scape and pedicel are whitish gray to yellow, the basal flagellomere is always gray. The same differences also apply to the coloration of the femora. Some populations have more yellowish femora, others grayish yellow, and some mostly gray.

Figures

FIGURE 48. Distribution map of Scatophila adamsi Cresson (circles), and S. hesperia Sturtevant & Wheeler (squares).

FIGURES 49–52. Head of Scatophila hesperia Sturtevant & Wheeler. 49. Male, latero-oblique view 50. Male, lateral view. 51. Female, latero-oblique view. 52. Female, lateral view. Scale bar = 0.2 mm.

FIGURES 53–55. Male terminalia of Scatophila hesperia Sturtevant & Wheeler. 53. Epandrium and cerci, posterior view. 54. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 55. Same, lateral view. Scale bar = 0.1 mm.

FIGURES 31–33. Head, thorax and wing of Scatophila. 31. S. variabilis Cresson, head and thorax, dorsal view. 32–33. Wing, dorsal view. 32. S. adamsi Cresson. 33. S. hesperia Sturtevant & Wheeler. 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.