Chironomid midges from early Eocene amber of France (Diptera: Chironomidae)
Author
Published, First
text
Zootaxa
2007
2007-02-05
1404
1
66
journal article
11755334
Ablabesmyia
(
Karelia
)
eocenica
n. sp.
(
Fig. 15
)
Etymology:
This species is named for the Eocene age of the fossil.
Diagnosis:
Gonostylus elongate and narrow, with characteristic cochleariform megaseta pointed; wing hyaline; no trace of coloured bands on legs.
Description:
Male head deformed; ocelli absent; antenna
1.08 mm
long, much longer than head, distinctly hairy, with 13 flagellomeres with long setae (shortest
0.02 mm
long, longest
0.46mm
long), pedicel broad and short, with few setae; 12
th
flagellomere long (
0.5 mm
), 13
th
with distinct apical nipple; eye bare but deformed, with apically expanded dorsomedial exptention; all palpomeres with numerous setae, no frontal setae, 2 postocular setae, inner vertical and outer vertical setae not visible, probably absent. Thorax
0.62 mm
long,
0.16 mm
wide,
0.75 mm
high; postnotum bare, with longitudinal median groove; numerous long setae on surface of scutellum; scutal tubercle not visible, may be absent; supraalar and prealar setae not visible; no anterior acrostichals visible, numerous long dorsocentral setae. Wing macropterous,
1.24 mm
long,
0.37 mm
wide, hyaline, with macrotrichia, covered with microtrichia; anal vein An
2
absent; radius with 3 branches R
1
and R
4+5
, R
2+3
apically forked into R
2
and R
3
; R
2
ending in R
1
, R
3
ending in costa; costa not produced after last branch of radius; only M
1+2
and M
3+4
present; crossvein MCu present; MCu beyond cubital fork; crossvein
RM
0.06 mm
long. Halter not visible. Fore femur
0.6 mm
long, tibia
0.62 mm
long, mid femur
0.7 mm
long, tibia
0.62 mm
long; tarsus
1.24 mm
long, hind femur
0.5 mm
long, tarsus
1.37 mm
long; all tibial spurs with lateral teeth, comblike; 2 hind leg tibial spurs, respectively
0.01 mm
long and
0.02 mm
long; ta4 cylindriform; hind tibial comb of 1 row. Abdomen
0.5 mm
long,
0.08 mm
wide; gonostylus elongate and narrow, megaseta clochleariform with pointed subterminal setae,
0.07 mm
long,
0.008 mm
wide; gonocoxite with long setae on outer surface,
0.09 mm
long,
0.06 mm
wide; anal point and volsellae not visible.
FIGURE 15.
Ablabesmyia
(
Karelia
)
eocenica
n. sp.
, holotype PA 534, drawing of male genitalia (scale bar = 0.1 mm).
Discussion:
In the key to dipteran families of
McAlpine (1981)
, this fossil falls in the
Tanypodinae
. In the keys to Nearctic tanypodine tribes and genera of
Fittkau (1962)
and
Oliver (1981)
and the key to Holarctic genera of
Murray & Fittkau (1989)
,
Ablabesmyia
(
Karelia
)
eocenica
is in the
Pentaneurini
because of the following characters: tarsomere 4 of all tarsi cylindrical, comb of hind tibia with single row of bristles, R
2
and R
3
present and joined, FCu proximal to or opposite MCu, costa not produced after last branch of radius, no posterior anepisternals or preepisternals, and posnotum always bare.
Ablabesmyia
(
Karelia
)
eocenica
would fall in the recent genus
Ablabesmyia
Johannsen, 1905
, based on the character ‘gonostylus elongate and narrow, with characteristic cochleariform megaseta’ and in the subgenus
Karelia
Roback, 1971
, based on the character ‘subterminal setae of gonostylus pointed’.
Ablabesmyia
(
Karelia
)
eocenica
has some similarities with
Coffmania
Hazra & Chaudhuri, 2000
, in the shape of its tibial spurs and long gonostylus, but the latter has a strong apical spur on its gonostylus, very different from the cochleariform megaseta of
Ablabesmyia
(
Karelia
)
eocenica
(
Hazra & Chaudhuri 2000
)
. It is not possible to compare our fossil to all the recent species of
Ablabesmyia
subgenus
Karelia
because they differ in the detailed shape of the apex of their gonostyli. Nevertheless, we prefer to name this species because it is the oldest representative of this genus.
Grund (2005)
described
Ablabesmyia electrohispaniola
from the Miocene Dominican amber, which has pigmented bands on the wings, unlike
A
.
(
K
.)
eocenica
. Recent species of
Karelia
are known from the Holarctic, Neotropical, Afrotropical, and Oriental regions. Thus, it is probably an ancient group, and its discovery in the early Eocene is not surprising.
Material:
Holotype
PA 534, (male).