Einfeldia pagana (Meigen, 1838)

Originally Chironomus paganus
Syn: Einfeldia synchrona Oliver 1971 (Oliver et al. 1990)

Specimens claimed to be this species are found in a number of BOLD Bins, but many are actually species of Benthalia
North American specimens are in BOLD Bin: BOLD:AAG5475

The description by Yamamoto (1995) seems to be the best description of Japanese material in English.  Yamamoto refers to a description in Japanese by Sasa (1993).  Some information on the larvae is given Yamamoto et al. (2015), but for the pupa, descriptions of European material must be used.

Adult:

Male: Wing length 3.4-3.9 mm, width 0.9-1.0 mm, 14-24 setae in squamal fringe. VR 0.92 (0.90-0.96); LR 1.72 (1.66-1.76); AR 3.35 (3.00-3.71).
Brownish black, with thorax largely blackish brown, vittae etc. brownish black; legs brown to dark brown.  Abdomen uniformly brownish black.
Head: Frontal tubercles minute 2.5-5.0 µm long and 5 µm wide.  Clypeal setae not given.  Palp segment lengths (1-5) (micron): 67 : 94 : 275 : 198 ; 264.
Antepronotum distinctly divided at middle by a conspicuous V-shaped notch, scutal tubercle indistinct, acrostichals normally developed.
Thoracic setae: acrostichals 8-12 (biserial); dorsocentrals 11-14; prealars 6-8; supra alar 1; scutellars 15-23 (biserial).
Leg length and proportions (micron)

 
Fe
Ti
Ta1
Ta2
Ta3
Ta4
Ta5
LR
F/T
PI
1530
1290
2000
1080
810
620
300
1.52-1.63
1.18
PII
1560
1460
890
550
420
300
210
0.58-0.63
1.07
PIII
1690
1830
1230
770
580
390
230
0.65-0.70
0.92

Note:  The LRs given by Yamamoto are clearly calculated in a different manner, so the values given by the usual formula (apparently his BV values) are provided.

Style inflated and abruptly constricted near the apex; anal point broad.

Female:  Coloration almost the same as male, but antepronotum and ground color of scutum ochreous, vittae black, scutellum pale brown.
Wing length 3.5-4.0 mm; width 1.0-1.2 mm.; VR 0.87 (0.85-0.90); 19-27 setae in squamal fringe.

Antennal proportions (µm): 173 : 113 : 122: 128 : 203; AR about 0.38, A5/A1 abt 1.17.
Frontal tubercle minute, 2.5-5.0 µm long and 2.5-7.5 µm wide. Clypeus with 35-55 setae setae.  Palp segment lengths (1-5) (µm): 67 : 90 : 241 : 211 : 321.
Thoracic setae: Acrostichals 7-13 (biserial); dorsocentrals 12-16 (uniserial); supraalar 1.
Leg length and proportions (micron) (values as for males)

 
Fe
Ti
Ta1
Ta2
Ta3
Ta4
Ta5
LR
F/T
Ta4/Ti
PI
1590
1270
2020
1040
790
600
300
1.45-1.63
1.25
0.47
PII
1640
1460
860
520
390
280
210
0.57-0.62
1.12
 
PIII
1650
1790
1150
700
540
340
320
0.62-0.66
0.92
 

Genitalia: Apodeme of VIII sternum well-developed, rounded postero-laterally, joined mesally; segment X with 4-5 setae. Cercus large, oblong.

Pupa: The only information for the pupa seems to be that for European specimens (e.g. Langton and Visser 2003):
Length of exuvia 7.5-9.0 mm.  Cephalic tubercles large, conical, curved, 145-190 µm long and 120-155 µm wide.Abdomen: Hook row of segment II entire, length of row 0.43-0.52x width of the tergite. Armament of tergites II-IV an undivided, usually extensive patch of strong points, on seg. II extending forward at least as far as setae D1. The patch on tergite VI is more of less reduced. Lateral tainiae of segments V-VIII: 4,4,4,5. Comb, or spur, of segment VIII of 4.5 (2-7) small teeth. Fringe of anal lobe with 63-86 taeniae.

Larva: In 2006, Yamamoto published some brief notes on the larva:
One pair of ventral tubules.  In 2015, Yamamoto et al. further noted the large oblong fenestra in the frontoclypeal apotome, a feature noted and illustrated for European specimens by Pinder and Reiss (1983); the rugosity anterior to the fenestra has not been confirmed in Asian specimens.

Cytology:  No information is available for Japanese populations.

Other descriptions of Einfeldia pagana indicate that it is a paler species, but it appears that Yamamoto is justified in considering this to be a seasonal variation of color – his specimens were collected in May.  However, there is doubt as to whether this material is actually E. pagana, since Yamamoto illustrates the antepronotum to have a distinct V-shaped notch, while the Holarctic keys indicate that the antepronotum is fused.  This, together with the fact that there is no Oriental specimen in the same BOLD Bin as the North American specimens, suggests that this material requires a new name.
The presence of this darker form may help explain why the species is confused with the generally dark Benthalia species.

Found: - a Holarctic species.
            Japan - Yoshimi, Shimonoseki (abt 33.9°N, 130.95°E), Yamaguchi Pref.
            There appear to be no specimens in the Chironomid DNA Barcode Database (at January 2020), nor does any Japanese specimen fall into the same BOLD Bin as the North American specimens (in the absence of any European specimens).
            Holarctic distribution (Belgium - region of Liége; Type locality).

Recorded from shallow eutrophic pools.

See also C. (Lobochironomus) dorsalisE. sasai.

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Created: 10 February 2020
Access: Unrestricted
Copyright © 2018, Jon Martin.