Plecia pinguis ( Heyden & Heyden, 1865 )

Skartveit, John & Wedmann, Sonja, 2021, A Revision of fossil Bibionidae (Insecta: Diptera) from the Oligocene of Germany, Zootaxa 4909 (1), pp. 1-77 : 33-34

Plecia pinguis ( Heyden & Heyden, 1865) (figs. 49–53, 147–155)

Protomyia pinguis Heyden & Heyden 1865: 24 .

Protomyia lapidaria Heyden & Heyden, 1865: 25 . Syn.n.

Bibio brachypteroides Meunier, 1915: 215 . Syn.n.

Plecia vulpina Statz, 1943: 27 . Syn.n.

Plecia Ƌ Nr. 3 Statz 1943: 30

Plecia ♂ Nr. 5 Statz, 1943: 31.

Plecia Ƌ Nr. 6 Statz, 1943: 32.

Redescribed (as Plecia lapidaria ) by Skartveit & Nel (2017).

Localities: Rott, Kleinkems. Also in Aix-en-Provence, France.

Material examined: Syntypes (females) Protomyia pinguis NHMUK 58811 (fig. 48), 58812. Syntypes (females) Protomyia lapidaria NHMUK In 58813 (fig. 49). NMS 1893.114.40 is probably the counterpart of this specimen. NMS 1893.114.39. Holotype (female) of Bibio brachypteroides Stadtmuseum Siegburg Rott 28 (fig. 50). Syntypes (females) Plecia vulpina LACMIP 2533.296ab / LACMIP Type 3391 (Fig. 51), 2533.297 / 3392. Illustrated specimen Plecia ♂ Nr. 3 LACMIP 2533.259ab/ 3389.

Additional material, males: LACMIP 2533.261ab, 2533.262ab, 2533.1216ab, 2533.1246, 2533.1251ab, 2533.1264, 2533.1271ab, 2533.1276ab, 2533.1277, 41997.102 (this is the counterpart of 2533.1246). Females: LACMIP 2533.284, 2533.1076, 2533.1145, 2533.1150, 2533.1199, 41997.97ab.

Description:

Female (N= 21, figs. 48–51, 147–150, includes measurements taken from Skartveit & Nel (2017), including some material from Aix-en-Provence):

Total length 4.8–6.8 mm (N=17).

Head (fig. 149): Length 0.55–0.96 mm (N=10), width 0.63–1.12 mm (N=14). Black, rather large, rounded. Ocellar triangle rather flat. Antennal flagellum rather long and 8–9-segmented.

Thorax (fig. 149): Length 1.5–2.4 mm (N=21), width 1.3–2.1 mm (N=9). Black. Sulci deep. Haltere brown.

Legs: Femora pale with dark tips, remaining parts dark brown, slender.

Wing (figs. 148, 150): length 4.9–7.0 mm (N=15), width 2.0– 3.1 mm (N=12), length/width = 2.17–2.47 (N=10). Oval, comparatively broad, anterior margin curved. Costa extends almost to apex of M 1. R 2+3 relatively long, oblique, basally nearly vertical with a bend close to base. Dark brownish fumose, veins dark brown, fine throughout. Fore margin distinctively curved, costal cell wide. Pterostigma indistinctive. Humeral vein present. Subcosta R 2+3 short, almost vertical, basally bent. Costa extends a little beyond apex of R 4+5. R 4+5 apically strongly curved. R-M slightly oblique. M-veins apically rather straight, fork of M narrow. CuA-veins apically straight. CuP basally strong but fading towards wing margin, running parallel with CuA and well separated from this vein. Vein measurements are given in Table 4.

Abdomen: Blackish-brown, cylindrical.

Male (N=10, figs. 52–53, 151–155):

Total length 8.0– 10.3 mm (N=4).

Head (fig. 153): Length 1.32–1.36 mm (N=2), width 1.21–1.29 mm (N=2). Black, oval. Ocellar triangle prominent. Palpus elongate, robust, subterminal segment nearly triangular, terminal segment conical. Antenna cylindrical, flagellum 9-segmented, 0.6 mm long (N=2), 0.10–0.13 mm wide (N=2).

Thorax (fig. 153): Length 2.1–2.5 mm (N=4), width 1.7–2.2 mm (N=3). Black, haltere blackish-brown. Notaulices rather deep and distinctive.

Wing (fig. 152): Length 6.0– 7.5 mm (N=4), width 2.2–2.6 mm (N=3), Length/width = 2.6–3.3 (N=3, likely some folding in the narrowest). Blackish fumose, costal cell darkened. Pterostigma oval, blackish-brown, rather indistinctive. Subcosta straight, rather strong, running well clear of R 1. Costa extends to half-way between apices of R 4+5 and M 1. R 2+3 medium-length, oblique, gently curved. R 4+5 apically rather strongly curved. R-M vertical. Fork of M rounded, M-veins apically gently curved. CuA-veins strong, apically straight. CuP straight, reaches wing margin. Vein measurements are given in Table 4.

Legs: not well preserved.

Abdomen (fig. 155): Length 4.9–5.3 mm (N=2), width 1.2–1.5 mm (N=2), black, somewhat conical.

Terminalia (figs. 154–155): Hypopygium 0.9 mm wide (N=1), rounded. Epandrium apically gently convex. Gonostyli attached laterally, very robust, rather short and straight.

Discussion:

Contrary to Meunier (1915), the type specimen of Bibio brachypteroides has a clear vein R 2+3 and is a typical Plecia . The body length of this specimen is about 6.5 mm and not 8 mm as stated in the original description.