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
Orthocladiinae
genus and species B
Description:
Head
0.16 mm
long, deformed; ocelli absent; antenna
0.25 mm
long, much longer than head, distinctly hairy, covered with long setae, pedicel broad and short, rounded, terminal flagellomere long, without subapical setae; eye bare, small dorsomedial extension; mouthparts lacking functional mandibles; 5 palpomeres with setae; postocular, frontal, and inner and outer vertical setae seemingly absent. Thorax
0.35 mm
long,
0.21 mm
wide,
0.36 mm
high; postnotum bare; setae on scutellum not visible; no scutal tubercle but tuft of microtrichia; no acrostichals, dorsocentrals uniserial; scutum without median longitudinal groove; 2 prealar and 1 supraalar setae; epimeron II and preepisternum bare. Wing macropterous,
0.55 mm
long,
0.2 mm
wide, hyaline, membrane bare; anal vein An
2
absent; radius with 2 branches R
1
and R
4+5
, R
2+3
seemingly absent; costa strongly extended beyond R, produced by
0.07 mm
; only M
1+2
and M
3+4
present; crossvein MCu absent; anal lobe not developed; squama bare. Halter
0.08 mm
long. Fore femur
0.12 mm
long, tibia
0.2 mm
long, tarsus
0.23 mm
long; mid femur
0.14 mm
long, tibia
0.16 mm
long, tarsus
0.2 mm
long; hind femur
0.18 mm
long, tibia
0.2 mm
long, tarsus
0.25 mm
long; ta4 of all legs cylindrical, not cordiform; fore tibia with 1 long spur, mid and hind tibiae with 2 long spurs. Abdomen
0.42 mm
long; gonostylus simple, elongate,
0.02 mm
long and
0.008 mm
wide, without strong apical megasetae, hinged to gonocoxite and folded inward; gonocoxite
0.06 mm
long,
0.03 mm
wide, with few long setae on outer surface; anal point and inferior volsella not visible.
4+5
Discussion:
In the key to the Holarctic orthocladiine genera of Cranston
et al
. (1989), this
Orthocladiinae
falls in couplet 91 because of the following characters: wing well developed, with R, M, and Cu veins distinct; without thick clavus; scutum without median longitudinal groove; eye bare; wing membrane bare; epimeron II and preepisternum bare; no lateral spines on spurs of mid and hind tibiae; anal point without strong lamellate setae laterally and apicodorsally; squama bare; male antenna without strong subapical seta; gonostylus simple; and tarsomere 4 cylindrical. Our fossil falls in the group of genera with a median tuft of microtrichia on the scutum, i.e.,
Acamptocladius
Brundin, 1956
,
Epoicocladius
Zavrel, 1924
,
Lappokiefferiella
Tuiskunen, 1986
,
Lindebergia
Tuiskunen, 1984
, and
Parakiefferiella
Thienemann, 1936
(for the Holarctic genera). It is not possible to see the genitalia clearly and determine if a pars ventralis is present. Thus, we cannot precisely determine affinities, but this fossil is different from all others of the Oise amber.
Material:
Specimen PA 709 (male).