There is no meaningful nearest neighbor to this bin.
Most specimens in this Bin are actually C. vitellinus, with only a few C. javanus.
C. javanus and C. vitellinus are closely related and there is clear evidence that some hybridization can occur in the limited area where both species occur together, e.g. in Malaysia.
Adult:
Many specimens attributed to C. javanus are actually C. vitellinus and C. javanus appears to have a relatively restricted distribution in India, Java, and Malaysia.
Other than the original description, the only reliable further descriptions for this species are those of Johannsen (1932) and Chaudhuri et al. (1992)(which appear to be larger, probably due to being reared in laboratory), plus a specimen from Penang:
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Female
Body length 3.69 (3.57-3.89) mm. Wing length not given.
Antennal segments (micron): 10 : 7 : 8 : 9 : 13; AR 0.38; A5/A1 1.3.
No information on palps, clypeus, thoracic setae or legs. Kieffer gives abdomen as green, unmarked. Cercus almost pointed at posterior end, large bulge on ventral margin.
Molecular: The mitochondrial CO1 barcode sequence is available in GenBank for a few specimens. Although the sequences in BOLD are in a single Bin, there is a suggestion that the distribution is bimodal, with the few C. javanus sequences separated from the main group. Thesequences differ by about 47 base positions (this does not include some rare polymorphisms where one or two C. vitellinus specimens carry the sequence present in C. javanus) and the majority are in the 5' region (as is common for differences between closely related Chironomus species):
There is one specimen from Penang in which the COI sequence is that of C. javanus, but the larva is typical of C. vitellinus – suggesting that the female parent was C. javanus and the male parent C. vitellinus. This is in the small region in which both species are known to co-exist.
Found:Type locality - Buitenzorg, Java, INDONESIA, also ¿Sumatra (Johannsen 1932).
India - Bankura, Chinsura, Dhaniakhali, all West Bengal (Chaudhuri et al. 1992); Madurai (9.925°N, 78.120°E), Tamil Nadu; Jammu &
Kashmir: University of Jammu Campus (32.73°N 74.87°E); Kasar Lake (18.82°N, 76.20°E)
Indonesia - ¿Sumatra.
Malaysia - Minden, Penang; Tregganu.
Apparently limited distribution through India, south east Asia,the Pacific regions and Africa, in rice paddies and small temporary water bodies, even sewage works.
Redescription of adults and immatures from Malaysia by Al-Shami et al. (2012) clearly refers to C. vitellinus but they did also collect at least one specimen of C. javanus (figure above).
Dr. Midya has an alternative species from India identified as C. javanus and L. Karunakaran described another species as C. javanus in an unpublished thesis (Martin 2022).