Fossil Bibionidae (Diptera: Bibionomorpha) from the late Oligocene of Bes-Konak, Anatolia, Turkey
Author
Skartveit, John
Author
Nel, André
text
Zootaxa
2012
3329
51
63
journal article
10.5281/zenodo.281232
cd359e84-c028-4f73-a84f-841017d87263
1175-5326
281232
Genus
Bibio
Geoffroy, 1762
Bibio
Goeffroy, 1762: 568
.
Type
species,
Tipula hortulana
Linnaeus, 1758
(by subsequent designation of
Latreille 1810
: 442
, validated by I.C.Z.N., 1957: 86).
FIGURE 1.
Bibio anatolicus
sp.n.
, male, holotype (MNHN B 47826).
Bibio anatolicus
sp. n.
(figs. 1–14)
Etymology: Named after
Anatolia
, home province of the Bes-Konak outcrop.
Diagnosis: A moderately large
Bibio
species. Wing light brown fumose, rather narrow, crossvein r-m approximately half as long as Rs. Antennal flagellum seven- or eight-segmented.
Hind
legs moderately clavate with first tarsomere not swollen. Lobes of epandrium short and widely separated.
Material:
Holotype
(male) MNHN B 47826, fig.1. The specimen is preserved lying on its side, but with the abdomen twisted so that the terminalia are seen from a dorsal view. Preservation of wings, body and hind legs quite good, of head and terminalia fair. The two front pairs of legs are poorly preserved. Pile of head and body not preserved.
FIGURE 2–6.
Bibio anatolicus
sp.n.
, male. 2. head (MNHN B 47754). 3. hind femur and tibia (MNHN B 48011). 4. wing (MNHN B 47826). 5. terminalia, dorsal view (MNHN B 47890). 6. gonocoxosternite, ventral view (MNHN B 47826). Scale = 1mm.
FIGURE 7.
Bibio anatolicus
sp.n.
, female, habitus (MNHN B 47789).
Other material, all in MNHN: five males (B 47751, B 47833, B 48011, IY 262, 1 unlabelled)
20 females
(BK 32, BK 92, BK 345, BK 605, BK 642, B 47578, B 47603, B 47728, B 47747, B 47771, B 47776, B 47789, B 47820, B 47884, B 47906, B 47926, B 47932, B 47972, B 48014, 1 unlabelled).
Description:
Male
: A moderately large species, body 8.0–
8.7 mm
long (N = 4), black with brownish legs. Head (
Fig. 2
)
1.45–1.60 mm
long (N = 3), plus rostrum and proboscis
0.75 mm
(N = 1). Flagellum apparently seven-segmented, but not well preserved in any of the male specimens. Pile not preserved.
Thorax black. Pile not preserved. Length
2.75–3.25 mm
(N = 3).
Legs: Brownish. Fore femur with long, black setae, tibia
1.85 mm
long (N = 1). Shape of mucron and spur of fore tibia not possible to see well in any of the male specimens.
Hind
femur and tibia (
Fig. 3
) strongly clavate.
Hind
femur dark basally, light yellowish-brown in apical half, 2.75–3.0 mm (N = 3) long,
0.19–0.25 mm
(N = 3) wide basally,
0.48–0.57 mm
(N = 4) apically.
Hind
tibia yellowish-brown basally, darkened apically,
2.6–2.9 mm
(N = 4) long,
0.22–0.28 mm
(N = 4) wide basally,
0.48–0.62 mm
(N = 4) apically. First tarsomere slightly swollen,
0.96 mm
long,
0.32 mm
wide (N = 1).
Wing (
Fig. 4
)
6.3–7.6 mm
long (N = 5),
2.5–2.75 mm
wide (N = 2). Light brown fumose, veins distinctive throughout, R-veins brown, more posterior veins more or less colourless. Pterostigma brown and distinctive. Crossvein r-m is roughly half as long as first sector of Rs.
Abdomen 4.4–5.0 mm long (N = 3), relatively slender, somewhat conical, tergites short and transverse. No trace of pile in the specimens at hand. Epandrium (
Fig. 5
) with two short, rounded lobes separated by a wide mesal cleft. Gonocoxosternite (
Fig. 6
) with a wide and shallow, mesal indentation. Gonostyli sickle-shaped, rather small and slender.
Female
(fig. 7): Body
10.2–12.7 mm
long (N = 5). Head (
Fig. 8
) 1.5–2.0 mm long (N = 4), black, antennal flagellum (
Fig. 9
) rather short and stout, eight-segmented. Ocellar tubercle prominent.
FIGURE 8–14.
Bibio anatolicus
sp.n.
, female. 8 head (MNHN BK 223). 9. antenna (MNHN B 47906). 10. fore tibia (MNHN BK 223). 11. hind leg (MNHN BK 223). 12. wing (MNHN B 47789). 13. terminalia, dorsal view (MNHN B 47789). 14. terminalia, lateral view (MNHN B 47906). Scale = 1mm.
Thorax 3.8–4.0 mm long (N = 3), yellowish-brown to dark brown dorsally, pleura darker. Legs brown, fore tibiae black, mid- and hind tibiae and all tarsal segments darker apically; fore tibia (
Fig. 10
) quite stout, spur short and curved, less than half as long as mucron. Mid- and hind femora clavate, rather thick, hind tibia slender, all tarsi slender.
Hind
leg as in
Fig. 11
.
Wing (
Fig. 12
) 8.0–
9.5 mm
long (N = 5), light brown fumose, venation as in male, veins brown, distinctive throughout. Pterostigma brown, distinctive.
Abdomen yellowish-brown to dark brown. Terminalia as in
Figs. 13–14
. Cerci rounded.
Remark: The antenna is well preserved in just one of the specimens at hand (female, MNHN B 47906,
Fig. 9
). In this case the flagellum consists of eight short, transverse segments. In several other specimens (e.g.,
Fig. 2
), the flagella appear to have just six or seven segments; they are, however, too fragmentary for a certain count.
Bibio nigricosta
sp. n.
(figs. 15–21)
Etymology: The species has a conspicuously darkened costal cell in the wing and is named accordingly. From Latin
niger
, black, and
costa
, rib. The species epithet is a noun in opposition.
Diagnosis: A large, robust species. Femorae red with black tips, tibiae and tarsi black. Wing rather short and broad, fumose with costal cell darkened, pterostigma black. Crossvein r-m half as long as to subequal to first sector of Rs. Legs robust, first hind tarsomere moderately swollen. Male gonostyli robust, epandrium rather small with rounded lobes.
FIGURE 15.
Bibio nigricosta
sp.n.
, male, holotype (MHNH BK 450).
FIGURE 16–20.
Bibio nigricosta
sp.n.
, male. 16. hind leg (MNHN BK 450). 17. wing. (MNHN BK 450) Position of crossvein m-cu not possible to ascertain in this specimen. 18. terminalia, dorsal view (MNHN BK 450). 19. habitus (MNHN B 47847). 20. female (?), wing (MNHN B 47961). Scale = 1mm
Remark. The species appears to be similar to
Bibio giganteus
Heer, 1849
,
Bibio linearis
Heer, 1849
, and
Bibio partschii
Heer, 1849
described from the Early Miocene of Radoboj (
Croatia
). It can be distinguished from these species by the much broader wing (length/width approximately 2.1 versus
2.7 in
Bibio giganteus
and
B. partschii
). The latter species also have crossvein r-m markedly shorter than half the length of first sector of Rs. The comparison is somewhat complicated by the fact that Heer’s three species were described based on females, while the
type
of
B. nigricosta
is a male. However, female bibionids tend to have slightly wider, not narrower, wings than males. We did not find the
type
of
Bibio linearis
, but judging from Heer’s description we believe that it is very similar to
Bibio giganteus
and
B. partschii
.
Material.
Holotype
(male) BK 450, fig. 15. The specimen is preserved in a spread position, dorsal side up. The head is poorly preserved but body, hind legs and wings are in a fairly good state of preservation. The two anterior pairs of legs are poorly preserved.
Paratype
: one female (B 47847), fig.19. Other material: partial specimen, sex uncertain (BK 21), one wing, presumed female (B 47961).
Description:
Holotype
(male) BK 450. Total length of
holotype
13.1 mm
; colour black except for reddish femora. Body pile apparently short and fine. Head
1.95 mm
wide,
2.05 mm
long (including rostrum), poorly preserved. Antennal flagellum poorly preserved but probably seven-segmented.
Thorax
3.5 mm
long,
2.15 mm
wide.
Wing (
Fig. 17
)
7.1 mm
long,
3.35 mm
wide, brown fumose, costal cell from pterostigma and two thirds of distance basad dark. Pterostigma brownish-black, distinctive. Veins distinctive throughout. Crossvein r-m approximately half as long as radial sector. Crossvein m-cu not visible in
type
.
Hind
leg (
Fig. 16
): Femur
2.6 mm
long,
0.68 mm
wide, reddish (probably bright red in life), clavate. Tibia 3.0 mm long,
0.64 mm
wide, black, truncate apically. First tarsomere
1.24 mm
long,
0.50 mm
wide, moderately swollen. Length of second to fifth tarsomeres 0.64, 0.46, 0.32,
0.42 mm
.
Abdominal tergites quite broad, clearly separated, in this respect similar to the recent species
Bibio marci
(L.).
Terminalia (
Fig. 18
): gonostyli quite robust. Lobes of epandrium rounded, indentation between them broadly V-shaped.
Female (specimen B 47847), fig. 19: body and head black, femora reddish. Thorax length
3.7 mm
. Fore tibia rather thick, black (only basal part visible). Wings as in male but larger (only basal half preserved). One large wing (BK 47961,
Fig. 20
) is presumably female. The basal and apical parts are not preserved, but the visible part is
9.1 mm
long, longer than the entire wing of the male.
A partial specimen (BK 21) consists of most of the thorax, the basal part of both wings and the posterior margin of the head including the ocellar tubercle. It is certainly conspecific with the
holotype
but the gender is uncertain.
Remark: It is not possible to see a crossvein m-cu in the wings of the
holotype
male; this may be partly due to the somewhat rough structure of the matrix. Nothing suggests that the vein should be absent in this species and the female specimen figured has a clear m-cu. This vein is probably present in all
Bibionidae
, but is often inconspicuous in fossilized wings.