Oriental Chironomus: C. sp. PK8

Chironomus species PK8

Adult not described.
Although adults were collected or reared with this sample, there were a number of different species included and there is no confirmation that any are associated with these larvae. Similarly, the larvae were a mixed sample, including those of the related C. flaviplumus Ty.B. In reality only the cytology could be confirmed as this species, as they are based on photographs of squashes made and identified by Pragya Khanna herself. However, one larva with cytology as the P.Khanna specimens has been found.

Pupa: Two pupal characters were observed in a prepual larva.
Pupal spur with 4 spines, taeniae on edge of swim fin from 1 to 2 rows posteriorly.

Fourth instar larva: Length not recorded.  Essentially a plumosus-type larva.  Ventral tubules well developed, anterior pair with 'elbows', posterior pair coiled.  Head capsule pale.
Mentum 183 µm wide (0.56 of VHL), with c2 teeth of the central trifid group moderately well separated (type III), 4th laterals not reduced (type I).  Width central tooth 23 µm; 32 µm between C2 teeth; central trifid tooth 46 µm; and between 1st laterals 60 µm.
Ventromentum abt 198 µm wide and 3.47 times wider than deep with about 54-58 striae, abt 1.08 times the mentum width.  VMR about 0.24 (0.21-0.25).
Pecten epipharyngis with about 18 even sharp teeth (Ty. A).
Antenna with basal segment about 3.1 times longer than wide, RO about a 0.33-0.41 of segment length from base of segment, AR not known; relative lengths of segments 115 : 37 : 9.5 : 11.5 : -.
Premandible with moderately sharp teeth, inner tooth about 3.3-3.7x width of outer tooth (Ty. B2).
Mandible abt. 476 mm long; 3rd inner tooth partially separated and colored (type IIB).   Striations near base not visible,  Pecten mandibularis with 12 taeniae; MTR about 0.38.

A number of characters differ from those of larvae of C. flaviplumus Ty. B, but are quite closely related.

Cytology: Four polytene chromosomes with the pseudothummi-cytocomplex combination BF, CD, AE, G. Nucleoli in arm F about 1/3 from the centromere and probably in arm D, but not in arm G. BR about middle of arm G which is closely paired. Photographs of the chromosomes supplied by Pragya Khanna indicate that heterozygous inversions occur in arms B, C, D, E and G.

Arm A1: possibly 1a-i, 2k-d, 9e - 4a, 13a - 14i, 3h-i, 12c - 10a, 2c - 1k, 3a-g, 15 Ð 19 i.e as the C. flaviplumus ty.A from Japan.
Arm B1: puff with dark bands distal near middle of arm, inversion near distal end.
Arm C1: Large inversion about 1/3 from distal end.
Arm D1: Possibly small nucleolus about middle of arm, small inversion near middle of arm.
Arm E1: 1 - 2e, 10 - 12, 3-2d, 9 - 4, 13 - 19 small inversion near middle of arm as holomelas
Arm F1: Nucleolus about 1/3 from centromere, small inversion near middle of arm, distal end 15d - 23.
Arm G1: small inversion in middle of arm, but may also be a more extensive complex inversion. i.e. at least 3 sequences?.

Polytene chromosome complement of C. species PK8 (courtesy P. Khanna)

Found: India - Bishnah wetland (32.70°N, 75.00°E), Jammu.
The karyotype can be identified by the absence of a nucleolus in arm G while nucleoli are developed in arms D and F. (Other species lack the nucleolus in arm G, but do not have nucleoli in both arms D and F).

DNA Sequence
No BARCODE sequence available.

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