Chironomus "orientalis"

            This species is related to C. flaviplumus in Japan, but requires a new name (Martin 2011b), so C. orientalis is suggested, as the species is widespread in Asia.

In Bold bin: BOLD:AAV5954.

Adults:


Adult from Queensland (photo by Graeme V. Cocks)

See here for proposed Holotype male.

Males:

C. "orientalis": Male hypopygium (left) and superior volsella (right) (note beaked shape)

AR about 2.44-2.93 (Specimens from Japan have an AR of 3.5-4.0, and probably should be considered as C. flaviplumus - see also under "Cytology")
Wing length: 2.85 - 3.15 mm; wing width 0.30 - 0.67 mm.  VR about 1.02-1.07; abt 2-4 SCf on brachiolum; 9-14 setae in squamal fringe.
Generally greenish, with light brown thoracic vittae and postnotum, legs unmarked, abdomen with brown saddle spots on segments II-V, then mostly brown. Legs pale.
Frontal tubercles about 33-39 µm, and about 13 µm wide.  About 11-22 clypeal setae.
Palp proportions (micron): 44 : 53 : 189 : 222 : 315

Thoracic setae - achrostichal about 12-18; dorsocentral about 12-18; prealar about 4-6; supra alar 1; scutellar in 2 approximate rows, 6-7 in anterior row, 11-17 in posterior row.

Leg lengths (micron) and proportions as follows:


Male
Fe
Ti
Ta1
Ta2
Ta3
Ta4
Ta5
LR
F/T
BR
PI
1350
975
1820
925
837
712
362
1.82-1.96
1.35-1.44
1.7-2.2
PII
1305
1155
750
395
268
168
125
0.62-0.67
1.11-1.17
-
PIII
1478
1385
1180
595
448
262
152
0.81-0.92
1.05-1.09
-

The superior volsella is essentially a D(e)-type of Strenzke (1959), although in some specimens is of a beaked type not illustrated by Strenzke (1959), i.e. it is marginal between Strenzke's D- and an almost S-type.
Setae on 9th tergite: 9-12; some setae on inferior volsellae with a simple or trifid fork; gonostylus reduces gently or sharply from about the midpoint.

Female:
Only three damaged specimens have been available for study, two with the head missing.
Wing length 3.19-3.53 mm; width at cross vein 0.83-0.90 mm, VR 0.83-0.93.$nbsp;$nbsp;About 2-3 SCf on brachiolum; 16 (14-18) setae on squamal fringe.
Head with frontal tubercles about 14 Ám long and 13 Ám wide; about 27-55 clypeal setae.
Antennal segments (microns): 190 : 127 : 147 : 121 : 215.$nbsp;$nbsp;AR about 0.37; A5/A1 about 1.13.
Thoracic setae - acrostichal about 13-17; dorsolateral about 32-44; prealar about 5; supra alar 1; scutellar in two approximate rows, 5 in anterior row; 11 in posterior row.

Leg proportions (micron)


Female
Fe
Ti
Ta1
Ta2
Ta3
Ta4
Ta5
LR
F/T
Ta4/Ti
PI
1640
1180
2290
1347
1102
1112
410
1.91-1.92
1.37-1.42
0.90-0.97
PII
1565
1400
828
438
309
192
143
0.58-0.61
1.11-1.14
-
PIII
1703
1640
1322
695
544
311
185
0.79-0.82
1.02-1.06
-
ant Ta4/Ti about 0.98; Ta3 and Ta4 subequal in length.

Abdomen pale (probably greenish); about 4 setae on segment X.
Fore Ta4 about same length as Ta3.  About 91-96 Sensilla chaetica on hind tibia.

Differences from other members of the C. samoensis/flaviplumus group:
Important features of males are the AR of 2.4-2.9 (lower than that of C. flaviplumus, but similar to C. samoensis), LR of about 1.8-2.0 and fore Ta5, which is about 0.35-0.4 length of Ti.  In Australia, it is the only presently known species with a beaked superior volsella.
In the female the fore legs are very long, with LR about 1.9, and Ta3 and Ta4 are about equal in length, only a little shorter than Ta2, ratio Ta4/Ti about 0.97
See here for descriptions of C. samoensis Edwards.
The Australian species is probably most closely related to the Japanese C. flaviplumus Tokunaga.

Molecular Sequence:
CO1 - GenBank accession nos. for Chinese specimens are KP902730 & -31, and for Thailand KT213029-038.  In BOLD they have 99.5% similarity to an early release sequence named as ChironomidaeGC sp. 7 from Queensland, Australia.

Proposed type series: Holotype male: Radon Creek, Kakadu National Park ANT.15.3 Egg mass #3, reared male 3.  Allotype female: details as holotype, female 1.

Found: Northern Territory - Radon Creek, Kakadu National Park; (12.75°S, 132.93°E); Twin Falls, off Jim Jim Road, Kakadu area
            (13.00°S, 132.58°E).
            Queensland - 3 km w. Sarina Beach (21.40°S, 149.25°E).
            The species is also widespread in the Orient:
            Bangladesh - Chittagong (22.4685°N, 91.7808°E)(BOLD)
            China - Yangtze River basin (30.09°N, 115.12°E) (GeneBank)
            Malaysia - Botanical Gardens, Univ. Malaya, Selangor (3.1295°N, 101.656°E)(BOLD)
            Thailand - Mahasarakham University (16.242°N, 103.260°E), and Ban Keab (16.250°N, 103.210°E), Kantharawichai Dist., Maha
            Sarakham; Ban Tha Reu (15.303°N, 103.392°E), Satuek Dist. Buri Ram.

Indian specimens described by Chattopadhyuy et al. (1991), are not the same species and one has been renamed C. indiaensis (Martin 2011b), while others are the widespread species PK2.

Australian adults of this species can be bred in the laboratory, as fertile egg masses were obtained from adults reared from wild collected larvae.  The related Japanese species has also been maintained in a laboratory culture (Elbetieha & Kalthoff 1988).

[ Return to Index | Go to C. "orientalis" immatures ]

Modified: 21 June 2020
Access: Unrestricted
Copyright © 2005-2020, Jon Martin.