Penthetria longiventris ( Théobald, 1937 ) Theobald, 1937

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 27-29

Penthetria longiventris ( Théobald, 1937) comb.n.

( Figs. 11 , 85 – 89 )

Plecia longiventris Théobald, 1937: 133 – 134.

Plecia superba Théobald, 1937: 134 – 135, nec Meunier, 1915. Syn.n.

Material examined. Paratype female FSL 391901 (fig. 11). This is the specimen depicted by Théobald (1937: XI: 8), from Célas.

Additional material: MNHN Monteils 11 (female), Monteils 13 (female), Monteils 16 (male), Monteils 20 (female), Monteils 21 (female), Monteils 26 (male), Monteils 50 (female), Monteils 51 (male), Monteils 108 (female), Monteils 145 (female), Monteils 161 (female).

Localities. Célas, Monteils.

Diagnosis. A medium-sized (8.5 – 11.5 mm) Penthetria . Most specimens are of a uniform, brown colour. Antennal flagellum 9-segmented. Male gonostylus very robust, short, sharply pointed. Female head rounded, ocellar tubercle not very prominent, compound eye relatively small.

Redescription. Male: Total length 8.5 – 10.5 mm (N=3). Entirely dark brown, probably black in life.

Fig. 86 . Male, head. MNHN Monteils 51.

Fig. 87 . Male, terminalia, dorsal. MNHN Monteils 51. Fig. 88 . Female, head and thorax, lateral. MNHN Monteils 13. Fig. 89 . Female, head and thorax, dorsal. MNHN Monteils 145.

Head (fig. 86): Length 1.4 mm (N=1), width 1.6 mm (N=1). Compound eye without conspicuous pile. Antenna relatively long, segments not possible to count in any of the specimens at hand.

Thorax: Length 2.1 mm (N=2). Haltere pale.

Wing: Length 6.8 mm (N=1). Hyaline to light brown fumose, veins concolourous with membrane, pterostigma invisible. Costa extends a little beyond apex of R4+5. Humeral vein present, Subcosta fine and long. Vein R 2+3 straight, oblique. R4+5 distally curved. Fork of M long and rounded.

Legs: Entirely slender. Fore femur 2.8 mm (N=1), fore tibia 2.7 mm (N=1). Hind femur 2.5 mm (N=1), hind tibia 2.6 mm (N=1).

Abdomen: Length 5.7 – 6.9 mm (N=3), width 1.1 – 1.3 mm (N=2). Slender, slightly conical.

Terminalia (fig. 87): Hypopygium width 0.9 – 1.1 mm (N=2), gonostylus length 0.38–0.45 mm (N=2). Gonostylus very robust, sharply pointed.

Female: Total length 8.5 – 11.5 mm (N=5). Dark brown.

Head (figs. 88–89): Length 1.13 – 1.39 mm (N=3), width 0.99 – 1.34 mm (N=4). Rounded triangular, widest near hind corners. Compound eye not prominent. Antenna relatively elongate, flagellum 9-segmented, 0.77 mm long (N=1), 0.15 mm wide (N=1).

Thorax: Length 2.4 – 3.2 mm (N=2), width 1.9 – 2.6 mm (N=2). Haltere brown.

Wing (fig. 85): Length 7.1 – 11.5 mm (N=7), width 3.2 mm (N=1), length/width = 2.70 (N=1), brown fumose, anterior part slightly darkened, veins dark brown, coloured throughout wing. Costa extends a little beyond apex of R4+5. Pterostigma not conspicuous. R2+3 almost straight, slightly curved. R4+5 distally curved. Fork of M long and rounded. CuA2 curved basad in distal part. Vein measurements in Table 1 .

Legs: Dark brown, relatively short, slender. Fore femur 2.1 – 3.2 mm (N=2), fore tibia 2.4 – 3.0 mm (N=2), hind femur 2.4 – 3.5 mm (N=3), hind tibia 2.3 – 4.0 mm (N=4).

Abdomen: Brown. Length 5.3 – 8.3 mm (N=5), width 2.2 – 3.2 mm (N=5).

Terminalia: Tergite IX mesally with a deep, U-shaped excavation. Cerci rather small, two-segmented, slender.

Figures

FIGURE 11. Penthetria longiventris, female. Paratype of Plecia superba Théobald, FSL 391901. FIGURE 12. Penthetria luberonica, male. Holotype of Penthetria luberonica sp. n., ECL 140.048 / 2.

FIGURES 85 – 89. Penthetria longiventris (Théobald, 1937) Fig. 85. Female, wing. MNHN Monteils 11.