Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits
Author
Skartveit, John
Author
Nel, André
text
Zootaxa
2017
4225
1
1
83
journal article
37263
10.5281/zenodo.259087
05be601b-f9f1-4952-ac09-7012ef31aab0
1175-5326
259087
4676EE59-569B-4197-B108-9B32FD88E68E
Penthetria nervisinuata
(
Théobald, 1937
)
comb.n.
(
Figs. 16
–
17, 98
–
102)
Plecia nervisinuata
Théobald 1937
: 407
Bibiopsis funebris
Heer
in
Heer & Gaudin, 1861
: 153
. (
nec
Penthetria funebris
Meigen, 1804
)
(nomen nudum)
A medium-sized
Penthetria
, rather stocky for the genus, entirely black as usual for the genus. The shape of vein R2+3 is characteristic: it is vertical at base, then turns 90° and runs parallel to R4+
5 in
the basal half, then turns forwards, meeting
Costa
at an almost 45° angle.
Material examined.
Holotype, female, FSL 391925 (fig. 14) from Aix. Paratype, female, FSL 391926.
Paratype, female, MNHN B 24519 from Céreste. Female, attributed by Heer to
Bibiopsis funebris
Heer
(ETHZ 164).
Localities.
Aix-en-Provence, Céreste.
FIGURES 98–102.
Penthetria
nervisinuata
(Théobald, 1937)
Fig. 98. Female, wing. ETHZ Aix 164.
Fig. 99
. Female, head and thorax, dorsal.
ETHZ
Aix 164.
Fig. 100
. Female (?), wing, RGL Céreste 192.
Fig. 101
. Male, terminalia, dorsal. MNHN Aix 981.
Fig. 102
. Male, wing. MNHN Aix 974.
Other material (
MNHN
): Males: Aix 779, 884, 974, 1085, P26. Females: Aix 332, 428, 645, 752, 799, 890, 926, 965, 1013, 1061, 1322, 1337, 1347, 1404. (RGL) Céreste 662. Isolated wing: Céreste 192. Female, labeled 164 (
ETHZ
, fig. 15).
Diagnosis.
The species is easily recognized by the long, horizontal vein R2+3, which is sharply bent basally and a bit sinuous in the middle. It is the only species in the French Oligocene material with a typical
Penthetria
wing venation. Specimens with preserved pigmentation are entirely dark with blackish-fumose wings.
Redescription.
Male: Total length 8.2
–
12.0 mm (N=5). The specimens are of a uniform, brown colour, probably not original colour.
Head: Length
0.96
–
1.30 mm
(N=5), width
1.03
–
1.41 mm
(N=4). Antenna robust, segments not possible to count.
Thorax: Length
2.2
–
2.9 mm
(N=5), width
1.7 mm
(N=1, smallest specimen).
Wing (fig. 102): Length
6.7
–
9.1 mm
(N=4), width
2.2
–
2.9 mm
(N=3), length/width = 2.98
–
3.30 (N=3). No pigment preserved in membrane, R-veins brown, posterior veins colourless.
Costa
extends to apex of R4+5. Humeral vein present, Subcosta terminating at origin of R2+3. Pterostigma oval, brown. R2+3 long, originating at base of pterostigma, bent in a right angle near base. Wing vein measurements in
Table 1
.
Legs: Slender, first tarsomere of hind leg slightly swollen and spindle-shaped. Fore femur
2.2 mm
(N=1), fore tibia
2.2
–
2.3 mm
(N=2), hind femur
2.7
–
3.5 mm
(N=3), hind tibia
2.5
–
3.8 mm
(N=3).
Abdomen: Length 5.4
–
8.0 mm (N=5), width
1.1
–
1.6 mm
(N=2). Cylindrical.
Terminalia (fig. 101): Gonostylus digitiform, curved, pointed. Epandrium wide, dome-shaped. Hypopygium width
0.83
–
1.15 mm
(N=4), gonostylus length
0.43 mm
(N=1).
Female: Total length 7.5
–
12.0 mm (N=16). Holotype and one paratype very dark, probably the original colour. Most of the other specimens have little or no pigment preserved.
Head (fig. 99): Length
0.77
–
1.16 mm
(N=11), width
0.82
–
1.28 mm
(N=17). Rounded. Compound eye medium-sized, slightly protruding. Ocellar triangle prominent but not very tall. Antenna robust, flagellum probably 8-segmented.
Thorax: Length
1.9
–
3.1 mm
(N=16), width
1.7
–
2.6 mm
(N=15). Sulci prominent. Haltere dark brown.
Wing (figs. 98, 100): Length 7.0
–
10.5 mm
(N=18), width
2.7
–
3.9 mm
(N=16), length/width = 2.44
–
3.00 (N=14). Blackish fumose, R-veins dark, posterior veins concolourous with membrane.
Costa
terminates at apex of R4+5. Humeral vein present, Subcosta terminating at or slightly beyond origin of R2+3. Pterostigma oval, black. CuAveins conspicuously strong. Vein R2+3 long and sinuous, basally vertical, bent 90° and then running parallel to R4+5 before bending toward costa in distal half. Relative length of stem and fork of CuA apparently quite variable. CuA2 apically curved basad. Wing vein measurements in
Table 1
.
Legs: Slender, covered with short erect dark pile. Length of fore femur 2.0
–
2.6 mm
(N=5), fore tibia
1.8
–
2.6 mm
(N=6), hind femur
2.1
–
3.1 mm
(N=5), hind tibia
1.9
–
3.5 mm
(N=6).
Abdomen: Length
5.1
–
8.3 mm
(N=14), width
1.9
–
2.8 mm
(N=13). Cylindrical.
Terminalia: Three spermathecae present. Cerci two-segmented, small and slender.