Bibio rottensis Statz, 1943

Skartveit, John & Wedmann, Sonja, 2021, A Revision of fossil Bibionidae (Insecta: Diptera) from the Oligocene of Germany, Zootaxa 4909 (1), pp. 1-77 : 49-51

Bibio rottensis Statz, 1943 (figs. 79, 200–202)

Bibio rottensis Statz 1943: 48–49 .

Localities: Rott

Material examined: Syntypes, females LACMIP 2533.238ab / LACMIP Type 3368 (fig. 79), 2533.239 / 3369, 2533.240 / 3370, 2533.241ab / 3371, 2533.242ab / 3372, 2533.243ab / 3373.

Additional material (females) Siegburg Rott-319, STIPB, one specimen without catalogue number.

Description:

Female (N=8, figs. 79, 200–202):

Total length 12.0– 14.8 mm (N=5)

Head (fig. 202): Length 1.5–1.9 mm (N=5), width 1.4 mm (N=1). Dark brown. Ocellar triangle not very prominent. Antenna short and stocky, cylindrical, flagellum 8-segmented, 0.56–0.81 mm long (N=5), 0.17–0.24 mm wide (N=5). Palpus robust. Complex eye medium-sized, about half length of head.

Thorax (fig. 202): Length 3.1–3.7 mm (N=3), width 2.6 mm (N=1). Pronotum and mesonotum yellowishbrown, pleurae and scutellum brown. Haltere yellowish-brown.

Legs: Yellowish-brown. Fore femur 1.9–2.2 mm long (N=2), 0.8 mm wide (N=1). Protibia 1.8–2.3 mm long (N=2), robust with relatively short spine, spur a little over half as long as spine. Hind femur and tibia slightly clavate, tibia with fine, straight apical spur. Hind femur 2.8–3.5 mm long (N=3), 0.56–0.59 mm wide (N=2), hind tibia 3.1–4.1 mm long (N=4), 0.49–0.53 mm wide (N=3). Tarsi slender, darkened apically. Pile not preserved in the specimens at hand.

Wing (fig. 201): Length 9.6–10.0 mm (N=3), width 3.3–3.8 mm (N=2), length/width = 2.6–3.1 (N=2). Hyaline, veins brown throughout. Pterostigma large, oval, yellowish-brown, rather indistinctive. Costa extends some distance beyond apex of R 4+5. Humeral vein not apparent, subcosta straight, fine and rather indistinctive. Basal Radial sector about three times as long as crossvein R-M. R 4+5 relatively straight. M-veins apically straight. Crossvein dM- Cu meets M at furcation. CuA-veins apically strong, curved basad. Vein measurements are given in Table 5.

Abdomen: Length 8.4–9.9 mm (N=4), width 2.5–2.9 mm (N=2). Cylindrical. Tergites and sternites yellowishbrown, membraneous areas brown. Cerci short and rounded. Three rounded spermathecae are visible in one specimen. Last tergite apically gently concave, last sternite with rather wide, U-shaped emargination.

Male unknown.

Discussion:

The species is rather similar to Bibio pannosus and may possibly be conspecific with this. However, none of the rottensis specimens available display the conspicuous, dark shading along the wing veins found in the type of pannosus , hence they are kept as separate species at least for the time being.