A Revision of fossil Bibionidae (Insecta: Diptera) from the Oligocene of Germany
Author
Skartveit, John
0000-0001-7614-3399
Author
Wedmann, Sonja
0000-0002-9778-4125
edmann@senckenberg.de
text
Zootaxa
2021
2021-01-19
4909
1
1
77
journal article
8640
10.11646/zootaxa.4909.1.1
fa031765-b474-48aa-9d7e-b62dd092cfa4
1175-5326
4448697
92ECCF97-7315-4A1A-A94A-537D0F331EBF
Bibio germari
Meunier, 1920
(figs. 72, 191–192)
Bibio germari
Meunier, 1920: 735–736
,
Statz 1943: 48
.
Bibio heydeni
Meunier, 1920: 736–737
,
Statz 1943: 50
. Syn.n.
Bibio comosella
Statz, 1943: 47
Syn.n.
Bibio
Ƌ
Nr. 4
Statz, 1943: 54
.
Localities
: Rott
Material examined
:
Syntypes
of
Bibio comosella
, two females LACM 2533.234ab / LACMIP Type 3364 (fig. 72), 2533.235ab / 3365. We have not found the types of
Bibio germari
or
B. heydeni
, but good photographs of the specimens were published by
Meunier (1920
, Figs. 10–11).
Additional material (male): LACMIP 2533.229 / LACMIP
Type
3359. This is the illustrated specimen of
Bibio
sp
. 4 sensu
Statz, 1943
. STIPB, unnumbered specimen (female).
Measurements for the
type
specimens of
Bibio germari
and
B. heydeni
are collected from
Statz (1943)
and the photos in the original descriptions.
Description
:
Female (N=3, figs. 72, 191–192):
Total length 11.0–
13.5 mm
(N=4).
Head (fig. 192): Length
1.6–1.8 mm
(N=4), width
1.5–1.6 mm
(N=2). Black. Ocellar tubercle big and prominent, antenna short and stout, flagellum probably 7-segmented.
Thorax (fig. 192): Length 3.5–4.0 mm (N=4). Brownish-black, haltere light brown.
Legs: Dark brown. Fore femur
2.6 mm
long, 1.0 mm wide (N=1). Fore tibia
2.4 mm
long (N=2), with spur a little over half as long as spine. Hind femur length
3.3–4.4 mm
(N=2), width
0.60–0.85 mm
(N=2). Hind tibia
3.3–3.4 mm
long (N=2), slender, sput short, all tars islender. Hind first tarsomere
1.1–1.2 mm
long (N=2),
0.26 mm
wide (N=1).
Wing (fig. 191): Length
8.5–10.2mm
(N=4), width 3.4–4.0 mm (N=3), length/width = 2.3 (N=1). Dark brown fumose, veins dark brown, distinctive throughout.
Subcosta straight
, strong and distinctive. Pterostigma oval, dark brown, distinctive.
Costa
extends to apex of R
4+5
. Humeral vein not apparent. Basal Rs about twice as long as R-M. Fork of M with relatively long stem and short fork, narrow, M-veins apically straight. Crossvein dM-Cu meets M
2
a little apicad of furcation. CuA-veins strong, apically straight, CuP straight, rather strong and prominent but fading towards apex. Vein measurements given in
Table 5
.
Abdomen: Length
6.9–9.4 mm
(N=4), width 3.0–
3.5 mm
(N=3). Cylindrical, rather stout. Last tergite apically gently concave. Cerci angular, rather large, yellowish.
Male (N=1):
Total length 10.0 mm
Head: Length
1.6 mm
, width
1.6 mm
. Rather small, not well preserved.
Thorax: Length
2.9 mm
, width
2.4 mm
. Pigmentation not preserved but probably blackish, notaulices rather deep. Haltere probably light brown.
Legs: Femora yellowish-brown. Fore tibia
1.7 mm
long, relatively slender. Fore tarsus blackish, slender, first tarsomere
1.5 mm
long. Hind femur
3.4 mm
long,
0.6 mm
wide, hind tibia
0.7 mm
wide, blackish, hind first tarsomere
1.1 mm
long,
0.4 mm
wide.
Wing: Length
7.6 mm
, width
2.6 mm
, length/width = 2.9. Light brown fumose, distal part of costal cell (area above Subcosta) strongly darkened, forming dark streak.
Costa
distinctively curved. Veins brown throughout, venation not well preserved. Vein measurements given in
Table 5
.
Abdomen: Length
6.5 mm
, width
2.2 mm
, quite broad, female-like, but terminalia idenifies the specimen as male. Densely covered by short, dark pile.
Terminalia: Hypopygium
1.3 mm
wide. Epandrium with very wide, V-shaped cleft. Gonocoxosternite posteriorly gently concave. Gonostyli not preserved.
Discussion
:
The
types
of
Bibio germari
and
B. heydeni
were supposed to be in Coll. Bauckhorn, Stadtmuseum Siegburg, but we have not succeeded in finding them. However, fairly good photographs of the specimens (
Meunier 1920
: pl. II, Fig. 10–11) combined with the descriptions of
Statz (1943: 48
, 50) allow us to identify the species reasonably well. According to
Statz (1943)
Bibio germari
should differ from
B. comosella
in having the setae on the tarsi fewer and longer. These setae are not well preserved in the
types
of
comosella
, and apparently not in the
type
of
germari
either, since no tarsi can be seen clearly in the photograph of the specimen. Tarsal setae have not been used in identifying recent species in the genus
Bibio
and its is not clear that they have any systematic significance.