Scatophila tuberculosa 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 : 54-57

13. Scatophila tuberculosa Cresson

Figs. 108 , 110–118 , 120

Scatophila tuberculosa Cresson 1935: 368 .— Sturtevant and Wheeler 1954: 199 [synonymy with Scatophila unicornis Czerny ].— Mathis and Zatwarnicki 1995: 286 [world catalog].

Scatophila carinata Sturtevant and Wheeler 1954: 188 [ United States. Iowa. Story: Ames (42°02.1'N, 93°37.2'W); HT ♂, USNM].— Deonier 1964: 109 [key; figure of head; Iowa]; 1965: 498 [natural history].— Wirth 1965: 758 [ Nearctic catalog].— Zatwarnicki 1987: 291 [checklist].— Mathis and Zatwarnicki 1995: 281 [world catalog]. Syn. Nov.

Diagnosis.—This species is distinguished from congeners by the following combination of characters: Body brown to blackish brown with some grayish microtomentose areas; small shore flies, body length 1.30–1.80 mm.

Head ( Figs. 110–114 ): Lateroclinate fronto-orbital seta moderately far forward, distance between lateroclinate fronto-orbital seta and medial vertical seta about double distance between medial and lateral vertical setae; gena high, approximately twice height of basal flagellomere; ventral margin of male face nearly flat, not distinctly emarginate; face of ♂ with a low, projected medial ridge invested with fine setulae; face of ♀ brown, microtomentose, not subshiny or lustrous; facial setae and setulae small, none prominent, generally oriented ventrally; lower facial seta not oriented laterally or slightly curved dorsally; gena comparatively short, gena-to-eye ratio 0.08–0.15.

Thorax ( Figs. 108 , 120 ): Mesonotum ( Fig. 120 ) brown with gray stripes along setal tracks; acrostichal setae generally small but irregular in size, arranged in 2 regular rows; dorsocentral setae 2, anterior seta sutural or just postsutural; scutum microtomentose, appearing dull. Wing ( Fig. 108 ) not strongly yellowish at base, mostly dark with distinct pattern of white spots; costal vein ratio 0.28–0.32; M 1 vein ratio 0.59–0.62; knob of halter yellow. Legs dark, blackish brown; midfemur of ♂ lacking row of spine-like setae; tarsi blackish reddish brown (basitarsomere) to black.

Abdomen ( Figs. 115–118 ): Tergites dark, blackish brown to black, posterior tergites shiny. Male terminalia ( Figs. 115–118 ): Epandrium in posterior view ( Fig. 115 ) generally diamond shaped, dorsal margin narrowly rounded, lateral margins widest at midheight and with shallow indentation, ventral margin broadly bifurcate, with narrow channel between lobe-like, broad symmetrical ventral extensions; epandrial setae about equal in length, sparser medially, more abundant with shorter setulae on ventral lobes; height of cercal opening about 1/3 epandrial height; cercus in posterior view ( Fig. 115 ) hemispherical; epandrium in lateral view ( Fig. 116 ) twice as high as wide, lateral margins irregular, with rounded ventral margin; aedeagus in lateral view ( Fig. 118 ) broadly V-shaped with 3 dorsal extensions, anterior 2 extensions truncate, posterior extension more robust and pointed apically, in ventral view ( Fig. 117 ) irregularly rectangular, lateral margins shallowly angulate, anterior and posterior margins truncate; ventral aedeagal process shallowly C-shaped; phallapodeme in lateral view ( Fig. 118 ) T-shaped, crossbar with lateral lobe-like extensions slightly curved posteriorly, medial process straight, linear, slightly shorter than crossbar; postgonite in lateral view ( Fig. 118 ) deeply V-shaped, dorsal arm subrectangular, 3–4X longer than wide, dorsal margin irregular, basal 2/3 more or less rectangular, posterior 1/3 narrowed, digitiform, bearing setulae apically and on lateral margins, ventral arm shallowly curved, moderately narrow, elongate, in ventral view ( Fig. 117 ) 3X longer than wide, irregularly tapered from base to narrowed posterior, digitiform extension, apex with short, lateral lobe; neohypandrium in lateral view ( Fig. 118 ) narrow, strap-like, irregularly curved, acutely pointed at both apices.

Type Material.— The holotype of Scatophila tuberculosa Cresson is labeled “ Atherton, M [iss]o[uri]./October/ TYPE No. 6520[,] Scatophila TUBERCULOSA E T Cresson,Jr. [pink; species name and number handwritten]. The holotype is double mounted (minute nadel in rectangular card block (black), is in fair condition, and is deposited in the ANSP (6520).

The holotype male of Scatophila carinata Sturtevant and Wheeler is labeled “AMES IOWA III-10-1945 [10 Mar 1945] T. POLHEMUS [handwritten]/ HOLOTYPE Scatophila carinata Stvt & Whle [pink].” The holotype was originally deposited in the insect collection of Iowa State University and was then transferred to the USNM where it is now deposited. The holotype is glued to a paper triangle and is in excellent condition.

Other Specimens Examined.— UNITED STATES. VIRGINIA. Fairfax: Great Falls ( Clay Pond ; 39°00.1'N, 77°15.4'W), 13–24 Jun 2006, 2007 , D. and W. N. Mathis , T. Zatwarnicki (5♂, 1♀; USNM); Turkey Run (mouth; 38°57.9'N, 77°09.4'W), 22 May–9 Nov 2006, 2007 , W. N. Mathis (5♂, 3♀; USNM) .

Type Locality.— United States. Missouri. Jackson: Atherton (39°11.2'N, 94°18.3'W) .

Distribution ( Fig. 110 ).— Nearctic : United States (Iowa, Missouri, Virginia).

Natural History.— Deonier (1965) reported this species from a mud-shore habitat in Iowa.

Remarks.— Cresson (1935: 368) described this species as S. tuberculosa and distinguished it in part by the projected or tuberculate ventral face of males. Sturtevant and Wheeler (1954: 199) wrote that Cresson’s species was a junior synonym of S. unicornis Czerny , basing their conclusion on Bolwig’s (1940a) illustrations of Czerny’s species, which were compared with their species. Sturtevant and Wheeler, however, did not dissect and study structures of the male terminalia. Our study of these species reveals that we are dealing with just two species, not three, and that the senior synonyms are S. tuberculosa and S. unicornis . Moreover, specimens of S. carinata are conspecific with S. tuberculosa with the latter name having priority (i.e., the senior synonym). Thus, our proposed synonymy of S. carinata with S. tuberculosa .

This species is placed in the noctula species group.

Figures

FIGURE 110. Distribution map of Scatophila bolwigi sp. nov. (squares), S. tuberculosa Cresson (triangles), and S. variofacialis Sturtevant & Wheeler (circles).

FIGURES 111–114. Head of Scatophila tuberculosa Cresson. 111. Male, latero-oblique view. 112. Male, lateral view. 113. Female, latero-oblique view. 114. Female, lateral view. Scale bar = 0.2 mm.

FIGURES 115–118. Male terminalia of Scatophila tuberculosa Cresson. 115. Epandrium and cerci, posterior view. 116. Same, lateral view. 117. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 118. Same, lateral view. Scale bar = 0.1 mm.

FIGURES 107–109. Head, thorax and wing of Scatophila. 107. Scatophila bolwigi sp. nov., head and thorax, dorsal view. 108–109. Wing, dorsal view. 108. S. tuberculosa Cresson. 109. S. unicornis Czerny. Scale bar = 0.2 mm.

FIGURES 119–121. Head and thorax, dorsal view. 119. Scatophila hirtirostris Sturtevant & Wheeler. 120. S. tuberculosa Cresson. 121. S. unicornis Czerny. Scale bar = 0.2 mm.