Scatella Robineau-Desvoidy, 1830

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 : 19-20

Scatella Robineau-Desvoidy, 1830

Figs 3, 4, 6–8 , 11, 12, 14, 15, 20, 23 , 27–30, 46 , 48–62 , 82, 83

Scatella Robineau-Desvoidy 1830: 801 . Type species: Scatella buccata Robineau-Desvoidy 1830 (= Ephydra stagnalis Fallén 1813 ), subsequent designation of Coquillett 1910: 603. – Harrison 1959: 236–244 [fauna of New Zealand]. – Mathis 1989: 648–649 [Australasian/Oceanian catalog]. – Mathis and Zatwarnicki 1995: 262–281 [world catalog].

Diagnosis. Scatella is distinguished from other genera of the tribe Scatellini by the following combination of characters: genal seta distinct, long; wings lightly to darkly infuscate with few to several white spots; epandrium generally ovoid in posterior view; phallapodeme absent; ejaculatory apodeme present; female cerci bearing one strong, prominent seta, inserted posteroventrally.

Description. Minute to large shore flies, body length 1.00–5.00 mm; blackish brown to cinereous species, rarely yellow; species macropterous or brachypterous.

Head ( Figs 3, 4 , 11, 12, 14, 15 , 48, 49, 54, 58, 59 ): 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 round; arista macropubescent to at most bearing short, dorsal, hairlike branches. Face conspicuously protruding, with an interfoveal, dorsal hump, uniformly sclerotized, no processes; facial setae conspicuous, 1–3 lateral facial setae curved laterodorsally or 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; palpus elongate, mostly dark, exceptionally yellow.

Thorax ( Figs 6, 7 , 20, 23 , 50, 51, 55, 60 ): Mesonotum generally dark colored, microtomentose, density of tomentum varying, generally unicolorous or with longitudinal stripes, not conspicuously multicolored with pattern of bands and/ or spots; dorsocentral setae usually 2 (0+2), sometimes 3 (1+2); scutellum flat, disc bare, bearing 2 pairs of marginal setae, sometimes 3; basal scutellar setae smaller than apical setae or equal; pleural region generally gray, lighter than mesonotum; postsutural supra-alar seta long, subequal in length to postalar seta or much smaller; legs typical, usually without distinct setae (forefemur with a row of short, stout setae anteroventrally in some species); color of tarsi variable; tarsal claws conspicuously curved and puvilli present below each claw (claws near straight and pulvilli absent in some Apulvillus species); stem of halter short, head oval, white. Wing generally palely to conspicuously infuscate with white spots, especially in cells r 2+3, r 4+5, and dm but exceptionally in cell r 1 and m 4; costa relatively long, extended to vein M 1, sometimes bearing spines; wing brachypterous in a few species.

Abdomen: Tergites gray to brown, microtomentose, sometimes with lighter posterior margins, or mostly shiny, blackish brown. Male terminalia ( Figs 56, 57, 61, 62 , 82, 83 ): sternites 5 and 6 well developed, very small or absent; epandrium as a plate generally ovoid in posterior view, with a narrow opening below the cerci; ventral projections of epandrium separated or indistinguishable; cercal cavity completely round; phallapodeme absent; ejaculatory apodeme present, L shaped, dorsoventrally flattened or crescent shaped, laterally flattened; gonite distinctly Y-shaped, elongate, sharply terminated, sometimes bearing setae on dorsal margin of anterior portion; aedeagus shoe-shaped in lateral view. Female terminalia ( Figs 8 , 27–30, 46 ): sternite 7 as one rectangular sclerite or 2 lateral, small, circular to partially quadrate sclerites; tergite 8 a complete arch; sternite 8 divided as 2 lateral, lunate sclerites; female cerci bearing one strong, prominent seta, inserted posteroventrally. Female ventral receptacle tubular shaped, one to five times longer than wide.

Distribution. Widespread: Afrotropical, Australasian/ Oceanian, Nearctic, Neotropical (especially Andean), Oriental, Palearctic.

Remarks. Scatella is a large genus with 139 species and occurs in all biogeographic regions except Antarctica. The principal characters for recognizing Scatella are structures of male terminalia and the strong and long setae of female cerci. Our analysis recognizes five subgenera: Parascatella Cresson, Teichomyza Macquart , Synhoplos Lamb , Apulvillus Malloch and Scatella (Scatella) . The latter subgenus includes species previously included in Neoscatella Malloch (see below).

Figures

Figures 3–9. (3)Scatella (Teichomyza) fusca, head anterior; (4) Scatella (Synsoplos) sturdeeanus, head lateral; (5)Lamproscatella cephalotes, head dorsal; (6–8) Scatella (Scatella) stagnalis, thorax lateral; (7) thorax dorsal; (8) female, abdomen lateral; (9) Haloscatella arichaeta, thorax dorsal. Abbreviations: anepst, anepisternum; ar, arista; d ped s, dorsal pedicel seta; dc s, dorsocentral seta; fr-orb s, fronto-orbital seta; fr vit, frontal vitta; gn s, genal seta; ial s, intra-alar seta; kepst, katepisternum; npl s, notopleural seta; p spal s, posterior supra-alar seta; pprn lb, postpronotal lobe; prepst, proepisternum; presut acr s, presutural acrostichal seta;presut spal s, presutural supra-alar seta;sctl, scutellum; spal s,supra-alar seta;sctl s,scutellar seta.

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.

Figures 24–47.Abdominal sternites and terminalia: (24)Philotelma sp.,female; (25)Philotelma sp.,male;(26)Ephydra (Ephydra) riparia, female; (27) Scatella (Scatella) stagnalis, female; (28) Scatella (Scatella) tenuicosta, female; 29, Scatella (Scatella) tenuicosta, male; (30) Scatella (Scatella) paludum, male; (31) Lamproscatella sibilans, epandrium and cerci, posterior; (32) Haloscatella arichaeta, epandrium andcerci,posterior;(33)Haloscatella karekare,epandrium and cerci,posterior;(34)Hyadina sp., aedeagus lateral;(35)Parydra aquila, aedeaguslateral;(36)Thinoscatella lattini, internal structures ofmaleterminalia (aedeagus[shaded], phallapodeme, gonite+hypandrium), lateral; (37) Diedrops steineri, aedeagus, lateral; (38)Lamproscatella sibilans, internal structures of maleterminalia (aedeagus [shaded],phallapodeme,gonite+hypandrium),ventral;(39)Lamproscatella sibilans, internal structuresof maleterminalia(aedeagus[shaded],phallapodeme,gonite+hypandrium), lateral;(40)Haloscatella arichaeta epandrium and cerci, lateral; (41) Haloscatella arichaeta, internal structures of male terminalia (aedeagus [shaded], phallapodeme, gonite+hypandrium),lateral;(42)Haloscatellakarekare,internal structures of maleterminalia (aedeagus[shaded],phallapodeme, gonite+hypandrium), ventral; (43) Haloscatella karekare, internal structures of male terminalia (aedeagus [shaded], phallapodeme, gonite+hypandrium), lateral; (44) Paracoenia bisetulosa, ventral receptacle lateral; (45) Notiocoenia paniculate, ventral receptacle lateral; (46)Scatella (Scatella) stagnalis, ventral receptacle lateral; (47)Philotelma defectum, ventral receptacle lateral.

Figures 48–62. Scatella fusca: (48) head, anterior; (49) head, lateral; (50) thorax, dorsal; (51) male mid leg, posterior; (52) epandrium and cerci posterior; (53) male internal terminalia, lateral.Scatella (Synhoplos) sturdeeanus: (54) head, lateral; (55) thorax, dorsal; (56) epandrium and cerci, posterior; (57) male terminalia, lateral. Scatella (Scatella) curtipennis: (58) head, anterior; 59, head, lateral; (60) thorax, dorsal; (61) epandrium and cerci, posterior; (62) male terminalia, lateral.

Figures 63-85. Male terminalia: (63–65) Notiocoenia acutella; (66–67) Halmopota mediterranea; (68–70)Limnellia huachuca; (71–73) Limnellia itatiaia; (74-77) Philotelma nigripenne; (78–81) Philotelma rossii; (82–83) Scatella (Synhoplos) neglectus; (84–85) Lamproscatella occidentalis.