C. 'atchleyi' Manuscript name
In BOLD Bin: BOLD:AAG7038
Chironomus nepeanensis is in the same Bin.
Adult:
Proposed Holotype male: Paringa, South Australia, ASA.22.1 Male 2 (J. Martin) 9-xi-1969.
Coloration generally as for C. nepeanensis although the median extension of the dark band on abdominal segments II-V is shorter than in C. nepeanensis.
Wing length 4.64 mm., width 1.06 mm., VR 0.98; 3 SCf on brachiolum, about 24 to 27 setae on squamal fringe.
Head: AR 3.59, frontal tubercles 37 µm long and 15 µm wide; clypeal width about 60% of the diameter of the antennal pedicel; 39 clypeal setae. Palpal lengths (µm) 78 : 86 : 275 : 270 : 425; P5/P4 1.57; P5/P3 1.55.
Thorax yellowish brown, stripes, postnotum and sternopleuron dark brown. Setae: about 20 acrostichals; 35 dorsocentrals (none anterior to the prarapsidal suture); 5 & 6 prealars; 1 supraalar; 3 rows of setae on scutellum, 18 in the 2 anterior rows, and 20 in the posterior row (total 38 setae).
Legs marked as in C. nepeanensis; lengths (micron) and proportions:
|
Fe
|
Ti
|
Ta1
|
Ta2
|
Ta3
|
Ta4
|
Ta5
|
LR
|
F/T
|
Ta4/Ti
|
PI
|
1710
|
1720
|
2355
|
1190
|
935
|
975
|
480
|
1.37
|
0.99
|
1.35
|
PII
|
1885
|
1770
|
1010
|
580
|
430
|
250
|
185
|
0.57
|
1.06
|
-
|
PIII
|
2050
|
2125
|
1545
|
830
|
635
|
375
|
230
|
0.73
|
0.96
|
-
|
Fore Ta4 longer than Ta3.
Abdominal markings as noted above; 13 setae in individual spots on tergite IX. Superior volsella a variant of Strenzke's E-type. Inferior volsella extending almost to end of anal point, setae simple. Gonostylus moderately swollen, reducing sharply about midpoint, then only slowly to disal end: 4+1 setae at tip.
All males:
Wing length about 4.46 (4.23-4.73) mm; width 1.05 (1.00-1.11) mm, VR 0.98 (0.95-1.03). 2-3 SCf on brachiolum, about 22.1 (16-27) setae on squamal fringe.
AR 3.55 (3.33-3.73); palp proportions (micron) 75 : 77 : 262 : 277 : 423; P5/P4 1.53 (1.41-1.57; P5/P3 1.62 (1.55—1.81). Frontal tubercles about 52.8 (25-68) µm and 2.26 (2.08-2.4) times longer than wide and narrower at base. Clypeus about 0.73 (0.60-0.78) times the width of the antennal pedicel, with about 36.8 (29-41) setae.
Thoracic setae: Acrostichal at least 21 (11-29); Dorsolateral 34.9 (31-38); Prealar 7.4 (5-11; Supra-alar 1; Scutellar about 40 (38-42) in 3 rows, abt 15-21 in 2 anterior rows and 19-27 in posterior row.
Leg lengths (micron) and proportions:
|
Fe
|
Ti
|
Ta1
|
Ta2
|
Ta3
|
Ta4
|
Ta5
|
LR
|
F/T
|
BR
|
PI
|
1645
|
1600
|
2360
|
1160
|
910
|
940
|
480
|
1.37-1.57
|
0.99-1.05
|
1.24-1.95
|
PII
|
1825
|
1710
|
990
|
580
|
430
|
260
|
190
|
0.57-0.59
|
1.05-1.09
|
-
|
PIII
|
2030
|
2090
|
1485
|
810
|
615
|
370
|
235
|
0.69-0.73
|
0.96-1.00
|
-
|
Fore Ta4 longer than Ta3. abt 38 SCh on hind Ta1
Abdominal markings as in C. nepeanensis; about 11.3 (10-13) setae in single pale spots on TIX.
Hypopygium of C. atchleyi
Superior volsella as in C. nepeanesis, Inferior volsella reaching almost to end of anal point with simple setae. Anal point narrow at base and rounded at distal end. Gonostylus only moderately swollen and narrows at about midpoint then only moderatelytly; about 5-8 setae with a gap after the first and/or before the last, at tip.
Larger size than C. nepeanensis, which may partly reflect its occurrence in cooler regions, although specimens raised under identical laboratory conditions were still larger.
Female:
Wing length about 4.72 (4.17-5.22) mm; width 1.33 (1.23-1.47) mm., VR 0.94-0.99. 2-3 SCf on brachiolum, about 27.6 (17-35) setae on squamal fringe.
AR 0.34 (0.30-0.37), antennal proportions (percentage of neck in brackets): 218 (32) : 160 (53) : 173 (52) : 202 (44) : 246; A5/A1 1.05-1.16. Frontal tubercles variable about 59.6 x 29.1 (15-86 x 13-38) µm, narrower at base and about 2.03 (1.2-2.6) times longer than wide.
Palp lengths (micron) 84 : 77 : 276 : 294 : 439; P5/P4 1.41-1.67; P5/P3 1.50-1.86.
Clypeus about 1.57-2.05 times the width of the antennal pedicel, with about 47.4 (41-55) setae.
Thoracic setae: Acrostichal about 24 (20-27); Humeral 9 (4-11) in a group or partial group; Dorsocentral 44.7 (38-55), DS+ humeral 54.8 (47-64); Prealar 7.4 (5-10); Supra-alar 1; Scutellars in 3 rows, abt 21 (16-27) in the 2 anterior rows and 22.5 (21-26) in posterior row (total 39-48).
Leg lengths (micron) and proportions:
|
Fe
|
Ti
|
Ta1
|
Ta2
|
Ta3
|
Ta4
|
Ta5
|
LR
|
F/T
|
Ta4/Ti
|
PI
|
1890
|
1710
|
2595
|
1260
|
1005
|
1035
|
505
|
1.39-1.70
|
1.08-1.14
|
0.52-0.65
|
PII
|
2000
|
1910
|
1020
|
580
|
415
|
260
|
200
|
0.52-0.54
|
1.03-1.06
|
-
|
PIII
|
2185
|
2205
|
1565
|
885
|
670
|
390
|
250
|
0.69-0.70
|
0.93-1.00
|
-
|
BR - 1.1-1.75
Abdomen generally dark - on anterior of TII, increasing on TIII then essentially all of the tergite. About 18 (13-25) setae on segment X, which is about 5.1 times longer than its greatest width; 4-7 setae on GpIX.
Cercus and segment X (at left) of C. atchleyi
Cercus roughly rectangular, with a ventral bulge, with dorsal edge slightly longer than the ventral edge which has a basal bulge.
Pupa: The only available information is from three prepupal larvae: 5-6 spines on the spur; and 99 taeniae in the developing anal fringe of a female.
Fourth instar larva: Go to C. 'atchleyi' immatures
South Australia - Paringa (-34.18°S, 140.97°E); Railway Lake, Belair National Park (-34.59°S, 138.38°E); Renmark
(-34.17°S, 140.73°E); Thorndon Park Reservoir (-34.875°S, 138.687°))(this sample was the 'C. nepeanensis' of Atchley & Martin 1971).
Victoria - 4 Km Anglesea (-38.38°S, 144.18°E); Lake Surprise, Nangiloc (B.V. Timms); Maribyrnong River, Hill Lake, Rowville;
Platypus Pond, Sunbury (both Carew et al. 2013).
This species is marginally larger than C. nepeanensis, with considerable overlap. The pupal spur appears to have more spines (5-6) than the majority of C. nepeanensis pupae (mean 3.6 and higher numbers only on one side of the pupa). It is, however, very closely related to C. nepeanensis but the known distributions do not overlap. If correct, this allopatric distribution may reduce selection for genetic isolating mechanisms.
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