Plecia sluiteri Meunier, 1917

Skartveit, John & Wedmann, Sonja, 2021, A Revision of fossil Bibionidae (Insecta: Diptera) from the Oligocene of Germany, Zootaxa 4909 (1), pp. 1-77 : 36-37

Plecia sluiteri Meunier, 1917 (figs. 56–57, 160–165)

Protomyia sluiteri Meunier, 1917: 14–15 .

Plecia sluiteri Meunier. Statz 1943: 5 .

Plecia lapidaria nigra Statz, 1943: 25 . Syn.n.

Plecia lapidaria ( Heyden & Heyden, 1865) sensu Statz, 1943

Plecia ♂ Nr. 15 Statz, 1943: 36.

Localities: Rott.

Material examined: Syntypes of Plecia lapidaria nigra (females): LACMIP 2533.277ab / LACMIP Type 3409 (fig. 56), 2533.278ab / 3410, 2533.279ab / 3411, 2533.280ab / 3412.

Additional material: Males: LACMIP 2533.267/ LACMIP Type 3398 (fig. 57, illustrated specimen), 2533.1158ab, 2533.1327. Females: LACMIP 2533.276, 2533.1068, 2533.1075ab, 2533.1149ab, 2533.1163, 2533.1169ab, 2533.1171ab, 2533.1184ab, 2533.1248, 2533.1262ab, 2533.1268, 2533.1284ab, 2533.1298ab, 2533.1299ab, 2533.1307ab, 2533.1308ab, 2533.1316ab. STIPB, Bonn: one unnumbered specimen. Isolated wings: LACMIP 2533.1160, 2533.1207, 2533.1208, 2533.1209, 2533.1309, 2533.1315.

Description:

Female (N=22, figs. 56, 160–162):

Total length 6.0– 8.5 mm (N=22)

Head (fig. 162): Length 0.59–0.98 mm (N=11), width 0.69–0.95 mm (N=12). Blackish brown, ocellar tubercle prominent. Complex eye rounded, medium-sized. Antenna with flagellum slender, 0.45–0.64 mm long (N=14), 0.09–0.13 mm wide (N=11), cylindrical, 8-segmented. Palpus slender, ultimate segment long, thin and cylindrical.

Thorax (fig. 162): Length 1.6–2.2 mm (N=23), width 1.4–1.7 mm (N=8). Blackish brown, haltere brown.

Legs: Brown, slender, relatively short. Fore femur brownish-yellow with dark dip. Hind tibia with two very fine, brown spurs. Fore femur 1.5–1.7 mm long (N=5), 0.32–0.38 mm wide (N=3), fore tibia 1.3–2.0 mm long (N=12), 0.16–0.23 mm wide (N=8), fore first tarsomere 0.71–0.86 mm long (N=7), hind tibia 1.7–2.3 mm long (N=9), 0.21–0.30 mm wide (N=5), hind first tarsomere 0.58–0.83 mm long (N=9).

Wing (fig. 161): Length 4.6–6.4 mm (N=34), width 1.9–2.7 mm (N=28), length/width = 2.3–2.9 (N=28). Brown fumose, rather wide, elliptical. R-veins much stronger than posterior veins. Humeral vein present, vertical. Pterostigma oval, light brown, not conspicuous. Subcosta straight , running well clear of R, distinctive. Costa extends to apex of R 4+5. R 4+5 apically moderately curved. R-M vertical. R 2+3 basally with a distinctive bend, otherwise straight and obligue. M- and CuA-veins apically gently curved. A rather distinctive pseudovein runs along CuA 2. CuP basally quite strong, fading apically but reaching wing margin, running parallel to and well separated from CuA 2. Vein measurements are given in Table 4 .

Abdomen: Length 4.0– 5.6 mm (N=22), width 1.3–2.1 mm (N=14). Dark brown, spindle-shaped. Cerci small and rounded.

Male (N=3, figs. 57, 163–165):

Total length 5.0– 5.5 mm

Head (fig. 165): Length 0.85 mm (N=1), width 0.83–0.89 mm. Dark brown. Antenna rather small, flagellum 0.33 mm long (N=1), 0.08 mm wide (N=1), 6-segmented?

Thorax (fig. 165): Length 1.5–1.9 mm, width 1.6 mm (N=1). Brownish-black, haltere light brown.

Legs: Fore femur yellowish with dark brown tip. Fore tibia and tarsus brown.

Fore femur 1.4 mm long, fore tibia 1.7 mm long, hind tibia 2.5 mm long, 0.28 mm wide (N=1)

Wing (fig. 164): Length 4.4–4.8 mm, width 1.3–1.6 mm, length/width = 3.0–3.2. Light brown fumose, costal cell not darkened. Veins strong. Humeral vein present. Subcosta straight , running very close to R for most of its length. Pterostigma invisible. Costa extends to half-way between apices of R 4+5 and M 1. R 2+3 oblique and straight. R 4+5 distally strongly curved. R-M vertical, rather short. Fork of M asymmetrical, veins gently curved. CuA 1 quite straight, CuA 2 distally bent basad. CuP straight. Vein measurements are given in Table 4 .

Abdomen: Length 2.9–3.5 mm, width 0.88–0.93 mm. Dark brown, cylindrical or a little conical.

Terminalia: Gonostylus robust.

Discussion:

We did not find the type of Protomyia sluiteri , however Meunier (1917: Fig. 13) published a reasonably clear photograph of the specimen which allowed us to compare it to the type material of Plecia lapidaria nigra in LACM. Meunier apparently based his description on a single specimen since he gave the length measurement as a single figure. There is one specimen labeled as Plecia sluiteri in STIPB, this agrees well with the specimen illustrated by Meunier.