Scatophila mystacina, Zatwarnicki & Mathis USNM, 2024

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 : 86-88

23. Scatophila mystacina sp. nov.

Figs. 203 , 205–211 , 217 , 220

Diagnosis.—This species is distinguished from congeners by the following combination of characters: Small shore flies, body length 1.50 mm.

Head ( Figs. 208–211 ): Mesofrons and fronto-orbits gray, fronto-orbits slightly darker, brownish gray. Antenna blackish gray, basal flagellomere densely microtomentose. Face of ♂ gray, ventral portion conspicuously protuberant ( Fig. 208–209 ), elongate, apex bearing numerous, slightly curved black setulae, these larger toward lateral margin of facial protuberance; face of ♀ more shallowly protruded than male, more arched, bearing longer setulae toward ventral margin on each side (210–211). Gena moderately high, height slightly more than length of basal flagellomere; gena-to-eye ratio 0.40.

Thorax ( Figs. 203 , 217 ): Mesonotum ( Fig. 217 ) mostly grayish tan, stripes faint or lacking; scutum mostly uniformly gray, microtomentose, dull, lacking stripes, but lighter in coloration between acrostichal tracks; disc of scutellum whitish gray; acrostichal setae in 2 rows on anterior third; 2 larger postsutural setae, smaller setae anterior of larger setae. Wing ( Fig. 203 ) with faint pattern of white spots, veins and crossveins slightly darker; veins R 2+3 and R 4+5 shallowly undulate near white spots; costal vein ratio 0.27; M 1 vein ratio 0.78. Legs with femora and tibiae dark gray, tibiae slightly yellowish at apices; tarsi pale, yellowish, especially basal tarsomeres, apical tarsomeres darker, gray to brown.

Abdomen ( Figs. 205–207 ): Tergites uniformly gray, concolorous with coloration of thorax. Male terminalia ( Figs. 205–207 ): Epandrium in posterior view ( Fig. 205 ) generally squatly oval except for broadly stepwise emargination at ventral margin, width almost equal to height, lateral margins shallowly curved with short, papilla-like projection at ventrolateral corner; dorsal margin of epandrium in posterior view ( Fig. 205 ) evenly rounded; length of epandrial setulae variable, those along ventral margin shorter, sparse along lateral margins; cercal cavity nearly round, only slightly higher than wide; cerci in posterior view ( Fig. 205 ) hemispherical, medial margin nearly straight; aedeagus in lateral view ( Fig. 207 ) broadly rounded basally, irregularly rectangular, dorsal margin deeply excavated, excavation V-shaped, depth of cavity longer than width of opening, posterior margin broadly truncate, in ventral view ( Fig. 206 ) more or less pentagonal, widest sub-basally, posterior margin tapered toward apical margin, apical margin truncate, basal margin concave; ventral aedeagal process in lateral view ( Fig. 207 ) C-shaped; phallapodeme in lateral view ( Fig. 207 ) very elongate, narrow, curved, keel evident as a medial thumb-like protuberance, dorsal length about equal to ventral length, in ventral view ( Fig. 206 ) T-shaped, basal crossbar slightly less than half length of medial process, crossbar extensions slightly tapered, especially apically, curved posteriorly; postgonite in lateral view ( Fig. 207 ) regularly, widely, and shallowly V-shaped, dorsal arm subrectangular, wider basally and anterior margin emarginate, ventral extension elongate, rod-like, parallel-sided, posterior apex tapered, thumb-like, narrow apex shallowly bifurcate, anteroventral corner distinctly produced, apex shallowly and narrowly bifurcate, bearing setulae on dorsal surface, in ventral view ( Fig. 206 ) with base wide and excavated, irregularly V-shaped, posterior extensions oriented medially, narrow, thumb-like; neohypandrium in lateral view ( Fig. 207 ) narrow, parallel-sided, irregularly and deeply sinuous.

Type Material.— The holotype male of Scatophila mystacina new species is labeled “ USA. UT. Grand: Green River (15.3 km N; 39°7'N, 110°6.6'W; 1225 m), 30 Jul 2007, D.&W.N. Mathis / USNM ENT 00250329 [plastic bar code label]/ HOLOTYPE ♂ Scatophila mystacina Zatwarnicki & Mathis USNM [red].” The holotype is double mounted (minute nadel in block of plastic elastomere), is in excellent condition, and is deposited in the USNM. Three paratypes (1♂, 2♀; USNM) bear the same label data as the holotype.

Type Locality.— United States. Utah. Grand: Green River (15.3 km N; 39°7'N, 110°6.6'W; 1225 m) .

Distribution ( Fig. 220 ).— Nearctic : United States (Utah).

Etymology.—The species epithet, mystacina , is of Greek derivation and means “mustache” and has reference to the dense patch of setae at the apex of the ventral facial protrusion.

Remarks.—This species is placed in the quadriguttata species group, where it is similar and closely related to S. conifera , differing by the more pronounced ventral facial protrusion of the male that bears a dense patch of curved, black setulae, and by structures of the male terminalia as noted in the key and respective descriptions.

Figures

FIGURE 220. Distribution map of Scatophila mystacina sp. nov. (circle), and S. rubribrunnea Sturtevant & Wheeler (squares).

FIGURES 202–204. Head, thorax, and wing of Scatophila. 202. S. hirsuta Sturtevant & Wheeler, head and thorax, dorsal view. 203. S. mystacina sp. nov. male, wing, dorsal view. 204 S. picta Sturtevant & Wheeler, wing, dorsal view. Scale bar = 0.2 mm.

FIGURES 205–207. Male terminalia of Scatophila mystacina sp. nov. 205. Epandrium and cerci, posterior view. 206. Internal male terminalia (gonite, phallapodeme, aedeagus, neohypandrium), ventral view. 207. Same, lateral view. Scale bar = 0.1 mm.

FIGURES 208–211. Head of Scatophila mystacina sp. nov. 208. Male, latero-oblique view. 209. Male, lateral view. 210. Female, latero-oblique view. 211. Female, lateral view. Scale bar = 0.2 mm.

FIGURES 215–219. Head, thorax, and wing of Scatophila. 215–216. Head of Scatophila picta Sturtevant & Wheeler. 215. Latero-oblique view. 216. Lateral view. 217. Scatophila mystacina sp. nov., head and thorax, dorsal view. 218–219. Wing, dorsal view. 218. S. pulchra Sturtevant & Wheeler. 219. S. rubribrunnea Sturtevant & Wheeler. Scale bar = 0.2 mm.