(Fig. 2 A)
Diagnosis. Aprionus karlssonorum is a new member of the Aprionus smirnovi Mamaev group of species (Jaschhof & Jaschhof 2009) as indicated by the simple, fingerless tegmen (↓). Among the species classified there, A. karlssonorum is distinguished by the short-subrectangular tegmen and small, simple, spineless gonostyli (↓). In Aprionus carpathicus Mamaev & Berest, a species known only from Ukraine, genital structures are faintly reminiscent of A. karlssonorum, but that species has regressive characters, such as flagellomeres with the crenulate whorls poorly developed.
Other male characters. Body size 1.1 mm. Head. Eye bridge 3–4 ommatidia long. Postocular bristles 9–10, in 1 row. First flagellomere with unusually long, swollen portion basally. Neck of fourth flagellomere as long as node; node with 1 complete and 3 incomplete crenulate whorls of sensory hairs, 2–3 thick hair-shaped translucent sensilla distally. Maxillary palpus 3 -segmented; first segment with hair-shaped translucent sensilla; apical segment longest. Wing. Apical portion of R 1 3 times as long as Rs. Legs. Claws thin, evenly, slightly curved, without teeth. Terminalia (Fig. 2 A). Ninth tergite short, with weak, concave anterior margin. Ventral gonocoxal bridge membranous; dorsal gonocoxal bridge very wide. Gonostylus tapered toward apex, dense, long microtrichia apically, 1–3 bristles subapically. Tegmen with dark border all around. Subanal plate lacking.
Etymology. This species is named after Dave and Maryna Karlsson, Färjestaden, Öland.
Types. Holotype. Male (CEC 92), Sweden, Dalarna, Hedemora, Kloster Nature Reserve 12 km NE Hedemora, swamp forest, 22 Aug. 2005, aspirator, M. Jaschhof (in NHRS). Paratype. Male (A 7606), Germany, Baden- Württemberg, Sandweier near Baden-Baden, 14 Aug.– 1 Sep. 2009, Malaise trap, D. Doczkal.