Penthetria subterranea ( 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 : 34-36

Penthetria subterranea ( Théobald, 1937) comb.n.

( Figs. 18, 103 – 106 )

Plecia subterranea Théobald, 1937: 233 .

Plecia bigoti Brongniart, 1879 (date taken from specimen label)—presumably an unpublished manuscript name in collection of EM

Plecia gracilis Brongniart, 1879 (date taken from specimen label)—presumably an unpublished cabinet name in a collection of EM

Material examined. Holotype (male) NMB F1404. Paratypes (males) NMB F1414/1, F1414/2. Additional material (2 males 11 females): EM 70002, 70009, 70010, 70011, 70013, 70015, 70017, 70201 (A 10.9), 70202 (A 10.13), 70203 (A 10.70), 70204 (A 10.93) (all in Coll. Coquand, EM, stored in FSL)

Localities. Kleinkembs, Aix-en-Provence.

Diagnosis. A medium-sized Penthetria (10 – 11 mm), male wing yellowish brown fumose. Vein R2+3 nearly straight. Male gonostylus digitiform, apically blunt.

Fig. 104 . Male, terminalia, dorsal. NMB F1404. Fig. 105 . Male, terminalia, ventral. NMB F1414/1. Fig. 106 . Female, wing. EM 70010.

Redescription. Male: Total length 8.5 – 11.0 mm (N=7). Brown.

Head: Length 1.0 – 1.2 mm, width 1.1 – 1.4 mm (N=4). Relatively small, broadly oval. Compound eye dichoptic? Flagellum 8-segmented, length 0.5 mm (N=1).

Thorax: Length 2.3 – 2.8 mm (N=7), width 1.8 – 2.0 mm (N=2). Black, convex. Sulci not particularly deep and conspicuous. Pile not conspicuous. Haltere brown.

Wing (fig. 103): Length 6.7 – 8.9 mm (N=5), width 2.5 – 2.9 mm (N=4), length/width = 2.89 – 3.22 (N=3). Yellowish fumose, rather narrow. Pterostigma small, pale brown. R-veins brown, posterior veins colourless. Costa extends to more than half-way between apices of R4+5 and M1. Subcosta long and prominent, humeral vein present. R2+3 oblique, nearly straight. Wing vein measurements in Table 1 .

Legs: Slender, yellowish, tarsi and apex of tibiae darker. Length of fore femur 1.9 mm (N=1), fore tibia 2.1 – 3.6 mm (N=3), hind femur 2.4 – 3.7 mm (N=3), hind tibia 2.6 – 3.6 mm (N=2), hind first tarsomere 1.1 mm (N=1).

Abdomen: Length 5.4 – 9.4 mm (N=7), width 1.2 – 1.5 mm (N=6). Long, slender, cylindrical. Pile not conspicuous.

Terminalia (figs. 104–105): Hypopygium width 0.7 – 1.4 mm (N=6). Epandrium apparently undivided with slightly convex posterior edge. Gonostylus 0.41 – 0.62 mm long (N=4), digitiform, curved, apically blunt.

Female: Total length 6.0 – 9.6 mm (N=9)

Head: Length 0.59 – 0.80 mm (N=6), width 0.71 – 0.94 mm (N=5). Black. Antenna robust, flagellum 0.47 – 0.57 mm long (N=2), 8-segmented?

Thorax: Length 1.8 – 2.5 mm (N=11), width 1.6 – 1.9 mm (N=4). Dark yellowish-brown. Haltere pale brownish.

Wing (fig. 106): Length 5.8 – 8.2 mm (N=10), width 2.2 – 3.2 mm (N=7), length/width = 2.57 – 2.99 (N=7). Hyaline to light brownish fumose, veins light brown. Venation as in male except that R2+3 is shorter and steeper. Wing vein measurements in Table 1 .

Legs: Scarcely preserved in the specimens at hand. Yellowish-brown. Length of fore tibia 1.8 – 2.0 mm (N=2).

Abdomen: Length 3.7 – 6.4 mm (N=10, obviously shrunk in some specimens), width 1.5 – 1.9 mm (N=4). Brown.

Terminalia: Cercus rather long, two-segmented, terminal segment slender.

Figures

FIGURES 103 – 106. Penthetria subterranea (Théobald, 1937) Fig. 103. Male, wing. NMB F 1404.