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
Chaetocladius petruleviciusi
n. sp.
(
Figs. 23
, 24)
Etymology:
This species is named for our friend and colleague Dr. Julian Petrulevicius (
Argentina
).
Diagnosis:
Eye apparently bare (if pubescent, not visible under high magnification); subapical setae on last male flagellomere; wing membrane bare, but with coarse punctation; scutum without median longitudinal groove; epimeron II and posterior mesanepisternum II bare; lateral spines of spurs of mid and hind tibiae diverging from shaft of spur (main diagnostic character); gonostylus single, without lobes, and not triangular in shape.
Description:
Head deformed; ocelli absent; antenna
0.60 mm
long, much longer than head, distinctly hairy, with 13 flagellomeres covered with long setae (shortest
0.06 mm
long, longest
0.3 mm
long), subapical setae, pedicel broad and short, rounded, 13
th
flagellomere
0.29 mm
long; eye apparently bare, may be pubescent but not visible, with small dorsomedial extension, with 3 rows of ommatidia at minimum width; mouthparts lacking functional mandibles; 5 palpomeres with setae; postocular and frontal setae not visible, may be absent, 6 inner and outer vertical setae. Thorax
0.61 mm
long,
0.57 mm
high; postnotum bare, with visible longitudinal median groove; surface of scutellum with few long setae; scutal tubercle absent; acrostichals not visible, probably absent, dorsocentrals uniserial; scutum without median longitudinal groove; 2 prealar setae, no supraalar setae visible, may be absent; epimeron II, posterior mesanepisternum II, and dorsal antepronotum bare. Wing macropterous,
1.19 mm
long,
0.26 mm
wide, hyaline, membrane bare, but with coarse punctation; anal vein An
2
absent; radius with 3 branches R
1
, R
2+3
and R
4+5
, R
2+3
not divided into R
2
and R
3
; only M
1+2
and
FIGURE 24.
Chaetocladius petruleviciusi
n. sp.
,
holotype
PA 15016, drawing of male genitalia; a, dorsal view; b, ventral view (scale bar =
0.2 mm
).
FIGURE 23.
Chaetocladius petruleviciusi
n. sp.
, holotype PA 15016, photograph of habitus.
M
3+4
present; crossvein MCu absent. Halter
0.15 mm
long. Fore femur
0.37 mm
long, tibia
0.51 mm
long, tarsus
0.50 mm
long; mid femur
0.39 mm
long, tibia
0.42 mm
long, tarsus
0.40 mm
long; hind femur
0.40 mm
long, tibia
0.46 mm
long, tarsus
0.61 mm
long; ta4 of all legs cylindrical, not cordiform; fore tibia with 1 long spur, mid and hind tibiae with 2 long spurs with lateral spines diverging from shaft of spur; ta1 and ta2 of mid and hind tibiae with 2 strong spurs, claw on all legs simple; pulvilli absent. Abdomen
1.05 mm
long; gonostylus single, narrow and elongate,
0.05 mm
long,
0.009 mm
wide, hinged to gonocoxite and folded inward, with apical megasetae; gonocoxite
0.2 mm
long,
0.04 mm
wide, with long setae apically and on outer surface; anal point present, but small and reduced.
Discussion:
This
Orthocladiinae
can be attributed to the genus
Chaetocladius
on the basis of the following characters and the key of Cranston
et al
. (1989): macropterous; wing without thick clavus; scutum without median longitudinal groove; eye apparently bare (if pubescent, not visible under high magnification); wing membrane bare; epimeron II and posterior mesanepisternum II bare; and lateral spines of spurs of mid and hind tibiae diverging from shaft of spur (main diagnostic character). This last character separates
Chaetocladius
from the other
Orthocladiinae
, except
Tokunagaia
Saether, 1973
, and some
Eukiefferiella
Thienemann, 1926
. The main differences between
Chaetocladius
and these two genera are the presence of a subapical seta on the last male flagellomere and the wing membrane with coarse (instead of fine) punctation (
Halvorsen & Saether 1987
, Cranston
et al
. 1989). Both these characters are present in
C. petruleviciusi
n. sp.
The gonostylus is single, without several lobes, and not triangular in shape, which suggests affinities with the subgenus
Chaetocladius
and the ‘
piger
,
vitellinus
&
acuticornus
groups’. It is not possible to compare this fossil with all recent species of this genus.
Evenhuis (1994)
listed no fossil
Chaetocladius
. Seredszus (2003) described (but did not name) a
Chaetocladius
from Baltic amber. It differs from
C. petruleviciusi
n. sp.
in its very large and long anal point.
Material:
Holotype
PA 15016, (male).