Penthetria Meigen, 1803

Skartveit, John & Nel, André, 2012, Fossil Bibionidae (Diptera: Bibionomorpha) from the late Oligocene of Bes-Konak, Anatolia, Turkey, Zootaxa 3329, pp. 51-63 : 58-59

Genus Penthetria Meigen, 1803

Penthetria Meigen, 1803: 264 . Type-species: Penthetria funebris Meigen, 1804: 104 (by subsequent designation and monotypy).

Penthetria beskonakensis sp. n. (figs. 21–28)

Diagnosis. Wing rather long and narrow, R2+3 long, subparallel to R4+5. Antenna robust and relatively long, flagellum 12-segmented. Male terminalia with robust gonostyli, epandrium bilobate, lobes rather narrowly separated. Female cerci two-segmented, basal segment large and triangular, distal segment slender.

Material: holotype (male) Labelled 8C, fig. 21. The holotype is smaller than the other specimens available (7.1 mm vs. 8.5–9.5 mm long) but otherwise is quite similar to them. The colours of the holotype appear faded but otherwise the state of preservation is very good. The apical parts of the wings are covered by rock. Other material: five males (BK 257, BK 442, B 47593, B 47598, B 47748), four females (B 47737, B 47793, B 47981, B 48072).

Description: Male: body, legs and wings all black. Total length 7.1–9.5 mm (N = 3). Head width 0.95–1.08 mm (N = 2). Thorax length 2.0– 3.2 mm (N = 3), width 2.1 mm (N = 1).

Legs: All parts slender. Length of fore tibia 2.25–3.05 mm (N = 3), mid tibia 1.6–2.0 mm (N = 2), hind tibia 2.55–3.2 mm (N = 3).

Wing ( Fig. 22 ) 5.0– 6.7 mm long (N = 3), rather narrow, pterostigma distinctive. Vein R2+3 long, subparallel to R4+ 5 in basal half. Crossvein r-m vertical, length approximately one sixth of Rs.

Abdomen slender, slightly conical. Pile not visible in the specimens at hand.

Terminalia ( Fig. 23 ): epandrium strongly bilobed, the two lobes slightly pointed, separated by a deep but narrow, U-shaped cleft. Gonostyli slender, mesally straight, distinctly curved only in apical third, pointed.

Female: Habitus as in fig. 24, total length 9.5–12.7 mm (N = 3). Head width 1.05 mm (N = 1). Head and thorax as in Fig. 25 . Antenna ( Fig. 26 ) robust with 12-segmented flagellum, the segments strongly transverse. Thorax length 2.25–2.7 mm (N = 2).

Legs: as in male. Length of hind tibia 3.15–3.5 mm (N = 2).

Wing ( Fig. 27 ) length 10.0 mm (N = 1), width 4.0 mm. Wider than in male. Pterostigma apparently indistinctive, but this may be due to fading. R2+3 long, rather straight. Crossvein r-m longer than in male.

Abdomen length 6.5–9.5 mm (N = 2), rather large, wider than thorax in the specimens at hand. Tergites and sternites with rather dense, short, dark pile.

Terminalia ( Fig. 28 ): cerci two-segmented, basal segment wide and triangular, terminal segment narrow and pointed. Tergite IX with slightly concave hind border.

Remark: The male and female have conspicuously differently shaped wings, but a marked sexual dimorphism in wing shape is common also among extant Penthetria species, being most extreme in the European Penthetria funebris Meigen, 1804 where the male is strongly brachypterous and flightless while the female has normally shaped, although short, wings.

Figures

FIGURE 22 – 28. Penthetria beskonakensis sp. n. 22. male, wing (MNHN B 47593). 23. male, terminalia, dorsal view (MNHN BK 223 8 C). 24. female, habitus (MNHN B 47793). 25. female, head and thorax (MNHN B 47981). 26. female, antenna (MNHN BK 614). 27. female, wing (MNHN BK 614). 28. female, terminalia (MNHN BK 614). Scale = 1 mm.