Bibio germari Meunier, 1920

Skartveit, John & Wedmann, Sonja, 2021, A Revision of fossil Bibionidae (Insecta: Diptera) from the Oligocene of Germany, Zootaxa 4909 (1), pp. 1-77 : 45-46

Bibio germari Meunier, 1920 (figs. 72, 191–192)

Bibio germari Meunier, 1920: 735–736 , Statz 1943: 48.

Bibio heydeni Meunier, 1920: 736–737 , Statz 1943: 50. Syn.n.

Bibio comosella Statz, 1943: 47 Syn.n.

Bibio Ƌ Nr. 4 Statz, 1943: 54.

Localities: Rott

Material examined: Syntypes of Bibio comosella , two females LACM 2533.234ab / LACMIP Type 3364 (fig. 72), 2533.235ab / 3365. We have not found the types of Bibio germari or B. heydeni , but good photographs of the specimens were published by Meunier (1920, Figs. 10–11).

Additional material (male): LACMIP 2533.229 / LACMIP Type 3359. This is the illustrated specimen of Bibio sp. 4 sensu Statz, 1943. STIPB, unnumbered specimen (female).

Measurements for the type specimens of Bibio germari and B. heydeni are collected from Statz (1943) and the photos in the original descriptions.

Description:

Female (N=3, figs. 72, 191–192):

Total length 11.0– 13.5 mm (N=4).

Head (fig. 192): Length 1.6–1.8 mm (N=4), width 1.5–1.6 mm (N=2). Black. Ocellar tubercle big and prominent, antenna short and stout, flagellum probably 7-segmented.

Thorax (fig. 192): Length 3.5–4.0 mm (N=4). Brownish-black, haltere light brown.

Legs: Dark brown. Fore femur 2.6 mm long, 1.0 mm wide (N=1). Fore tibia 2.4 mm long (N=2), with spur a little over half as long as spine. Hind femur length 3.3–4.4 mm (N=2), width 0.60–0.85 mm (N=2). Hind tibia 3.3–3.4 mm long (N=2), slender, sput short, all tars islender. Hind first tarsomere 1.1–1.2 mm long (N=2), 0.26 mm wide (N=1).

Wing (fig. 191): Length 8.5–10.2mm (N=4), width 3.4–4.0 mm (N=3), length/width = 2.3 (N=1). Dark brown fumose, veins dark brown, distinctive throughout. Subcosta straight , strong and distinctive. Pterostigma oval, dark brown, distinctive. Costa extends to apex of R 4+5. Humeral vein not apparent. Basal Rs about twice as long as R-M. Fork of M with relatively long stem and short fork, narrow, M-veins apically straight. Crossvein dM-Cu meets M 2 a little apicad of furcation. CuA-veins strong, apically straight, CuP straight, rather strong and prominent but fading towards apex. Vein measurements given in Table 5 .

Abdomen: Length 6.9–9.4 mm (N=4), width 3.0– 3.5 mm (N=3). Cylindrical, rather stout. Last tergite apically gently concave. Cerci angular, rather large, yellowish.

Male (N=1):

Total length 10.0 mm

Head: Length 1.6 mm, width 1.6 mm. Rather small, not well preserved.

Thorax: Length 2.9 mm, width 2.4 mm. Pigmentation not preserved but probably blackish, notaulices rather deep. Haltere probably light brown.

Legs: Femora yellowish-brown. Fore tibia 1.7 mm long, relatively slender. Fore tarsus blackish, slender, first tarsomere 1.5 mm long. Hind femur 3.4 mm long, 0.6 mm wide, hind tibia 0.7 mm wide, blackish, hind first tarsomere 1.1 mm long, 0.4 mm wide.

Wing: Length 7.6 mm, width 2.6 mm, length/width = 2.9. Light brown fumose, distal part of costal cell (area above Subcosta) strongly darkened, forming dark streak. Costa distinctively curved. Veins brown throughout, venation not well preserved. Vein measurements given in Table 5.

Abdomen: Length 6.5 mm, width 2.2 mm, quite broad, female-like, but terminalia idenifies the specimen as male. Densely covered by short, dark pile.

Terminalia: Hypopygium 1.3 mm wide. Epandrium with very wide, V-shaped cleft. Gonocoxosternite posteriorly gently concave. Gonostyli not preserved.

Discussion:

The types of Bibio germari and B. heydeni were supposed to be in Coll. Bauckhorn, Stadtmuseum Siegburg, but we have not succeeded in finding them. However, fairly good photographs of the specimens ( Meunier 1920: pl. II, Fig. 10–11) combined with the descriptions of Statz (1943: 48, 50) allow us to identify the species reasonably well. According to Statz (1943) Bibio germari should differ from B. comosella in having the setae on the tarsi fewer and longer. These setae are not well preserved in the types of comosella , and apparently not in the type of germari either, since no tarsi can be seen clearly in the photograph of the specimen. Tarsal setae have not been used in identifying recent species in the genus Bibio and its is not clear that they have any systematic significance.