Scatella (Parascatella) Cresson, 1935

Costa, Daniel N. R., Mathis, Wayne N., Marinoni, Luciane & Sepúlveda, Tatiana A., 2024, Phylogeny and taxonomy of the shore-fly tribe Scatellini (Diptera: Ephydridae: Ephydrinae), Zoologia (e 23100) 41, pp. 1-35 : 21

Scatella (Parascatella) Cresson, 1935

Figs 12, 14

Parascatella Cresson 1935: 357 (as a genus; feminine). Type species: Scatella pilifera Cresson 1931 , original designation. – Sturtevant and Wheeler 1954: 178 [revised status]. – Mathis and Zatwarnicki 1995: 268–270 [world catalog].

Diagnosis. Specimens of Scatella (Parascatella) are similar to those of Scatella but may be distinguished by the following combination of characters: facial setae lateroventrally curved; proepisternum bearing macrosetae; postpronotum with 1–3 setae plus scattered setulae; postsutural supra-alar seta as long as postalar seta; wing spots evident.

Description. Moderately small to moderately large shore flies, body length 2.50–4.90 mm; blackish brown to cinereous species.

Head ( Figs 12, 14 ): Frons dull usually with distinct, subshiny to shiny frontal vitta; lateroclinate fronto-orbital seta 2, rarely 3. Antenna short, dark; pedicel with strong seta ventrally; basal flagellomere brown; arista macropubescent to at most bearing short, dorsal, hairlike branches. Face conspicuously protruding, facial setae conspicuous, lateral facial setae ventrally curved, indistinctly from medial facial setae; small to long ventroclinate setae along oral margin. Eye usually nearly round. Gena short to moderately high, usually bearing a large seta.

Thorax: Mesonotum microtomentose, density of tomentum varying, generally unicolorous or with longitudinal stripes; dorsocentral setae 3 (1+2, usually with several smaller setae between larger bristles); acrostichal setae in 2 rows extending to scutellum, equal in length; prescutellar acrostichal absent; postsutural supra-alar seta long, subequal in length to postalar seta; postpronotum with 1 long setae; scutellum with 2–3 setae, basal scutellar setae long or short; legs typical, usually without distinct setae (forefemur with a row of stout setae anteroventrally and posteroventrally in some species); color of tarsi variable; halter pale yellowish; Wing with faint white spots; costal vein bearing spinelike setae along costal margin.

Abdomen: Tergites gray to brown, microtomentose, sometimes with lighter posterior margins, or mostly shiny, generally lacking prominent macrosetae. Male terminalia: sternites 5 and 6 absent. Epandrium and internal structures typical of Scatella ; ventral projections of epandrium separat- ed; ejaculatory apodeme present, crescent shaped, laterally flattened. Female terminalia: typical of Scatella ; sternite 7 as a rectangular sclerite; female ventral receptacle tubular shaped, as long as wide.

Distribution. Neotropical (especially Andean transition).

Remarks. Parascatella was originally described as a genus and comprises 13 species from western South America. Nothing is known about the natural history of this subgenus except that adults are associated with aquatic or semiaquatic habitats. Some species exhibit sexual dimorphism in the maculation pattern of wings, and/or in the shape of tarsomeres. Mathis and Shewell (1978) presented a revision and a cladistics analysis of the subgenus.

Figures

Figures 10–23. Head, wing and legs characters: (10) Limnellia sp., head anterior; (11) Scatella (Scatella) sp., head anteri- or; (12) Scatella (Parascatella) sp., head anterior; (13) Hyadina sp., head lateral; (14) Scatella (Parascatella) pilifera, head anterior; (15) Scatella (Scatella) stagnalis, mouth parts; (16) Philotelma sp., head lateral; (17) Physemops nemorosus, head anterior; (18)Ephydra riparia, mouth parts; (19) Scatophila caviceps, wing; (20) Scatella (Scatella) stagnalis, wing; 21, Dagus rostratus, wing; (22) Scatophila mesogramma, male, mid femur posteroventral; (23) Scatella (Scatella) stagnalis, male, fore femur anteroventral.