Meigen, 1830 : 118 Becker, 1902 : 310 S. stagnalis ( Fallén, 1813 ) Collin, 1930 : 136 Collin, 1930 : 138 S. tenuicosta Collin, 1930 Olafsson, 1991 : 31 Taxonomic notes on the genera Scatella and Scatophila (Diptera: Ephydridae) with a remark on Trixoscelis chilensis (Trixoscelididae) Zatwarnicki, Tadeusz Irwin, Anthony G. Zootaxa 2018 2018-01-31 4377 1 91 109 88R3C (Meigen, 1830) Meigen 1830 [151,673,1132,1159] Insecta Ephydridae Scatella GBIF Animalia Diptera 5 96 Arthropoda species lacustris Scatella     Ephydra lacustris  Meigen, 1830: 118.    Scatella lacustris:  Becker, 1902: 310(combination), synonymy with  S. stagnalis( Fallén, 1813).  Scatella tenuicosta  Collin, 1930: 136,  new synonym.    Scatella thermarum  Collin, 1930: 138, synonymized with  S. tenuicosta Collin, 1930by  Olafsson, 1991: 31.   Type material examined:one female lectotype of the senior synonym, herein designated, double mounted on a thin pin in a paper square, in good condition, but covered with some dust, right wing folded, labelled: “26.98 40" (rounded label), on the reverse “Meigen” (handwritten), “ lacustris” (handwritten) preserved in MNHM; the male lectotype of the junior synonym, herein designated, in good condition labelled: "Pitsea 7/6/94", " Scatella tenuicosta Collin" - 1 ♂; paralectotypes: two females with the same labels (one with posterior margin of the right wing slightly torn); a male in good condition labelled: "Pitsea 7/6/94", " Scatella tenuicosta Collin Det. I. Lansbury197"; a male with removed abdomen, labelled: "Walton-on-Naze 9. 6. 0 8 Col. Y.", its terminalia in Canada balsam on a celluloid square bearing a label: "Walton-on-NAZE 9. VI. 1908Col. Yerbury", " Scatella tenuicosta Collin", all preserved in OUMNH. According to Mathis and Zatwarnicki (1995)some type material is also present in NHMUK and MZLU.  Other material examined:Numerous specimens from Austria, Belgium, Bulgaria, Czechia, Denmark, Finland, France, Germany, Great Britain, Greenland, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Poland, Portugal, Romania, Russia, Spain, Sweden, Switzerland, United Kingdom, United States( Arizona, Illinois).  The typelocality of senior synonym was not given, and the specimen was possibly collected in CentralEurope ( Franceor Germany).  Typelocality of the junior synonym: Essex: Pitseaand Walton-on-Naze; Dorset: Arne; Glamorgan: Porthcawl; Norfolk: Palling-on-sea; Suffolk: Aldeburgh, Felixstowe, Butley, Newmarket( Great Britain).   Diagnosis.The species is closely related to  S. stagnalis(Fallén), but is distinguished from other species by the wing with spot 3 (distal spot in R5) narrowest in middle; costal section II longer than III ( Fig. 8); female sternite 7 a single sclerite. Male terminalia illustrated by Olafsson (1991; figs 15d–h, page 30) and Beshovski (2009, fig. 147, pages 370–371).   Distribution.Afrotropical:  CapeVerdeIslands. Nearctic: Greenland, United States( Arizona, Illinois, Oregon). Palaearctic: Austria, Azores, Belgium, Bulgaria, Canary Islands, China, Cyprus, Czechia, Denmark, Egypt, Finland, France, Germany, Great Britain, Greece, Hungary, Iceland, Ireland, Italy, Jordan, Madeira Islands, Norway, Poland, Russia(European Territory), Serbia, Slovakia, Spain, Sweden, Switzerland, Tunisia, Turkey.   Remarks.Characters of the lectotype: wing spot 3 narrowest in middle; costal section II longer than III; female sternite 7 a single sclerite, characterize  S. tenuicostaand distinguish it from  S. stagnalis(Fallén). Becker (1902)had not realised there was a second species and incorrectly placed  lacustrisin synonymy with  stagnalis. 1806155490 France Central 5 96 1 Central holotype 1806155498 United Kingdom Newmarket Pitsea Butley 5 96 1 Essex holotype