Oriental Chironomus: C. flaviplumus type B

Chironomus flaviplumus Type B

It is not clear that there is a valid name for this species as names that have been applied to this taxon do not fit the morphology and other species are insufficiently described to be safely applied.
Uncertain synonym: C. incertipenis aut.Ð not Chaudhuri et al. (1992)?
C. ramosus sensu Laviad-Shirit et al. (2020) and Sela et al. (2021) - not Chaudhuri et al. (1992)
Korean specimens under the name C. flaviplumus (GenBank accession numbers JF412075 - 077) are Chironomus yoshimatsui.

This type was identified as C. flaviplumus by H. Yamamoto. BLAST comparisons of available sequences in GenBank or the BOLD Database reveals that the species is widely distributed from India (sometimes as C. ramosus), Japan, Pakistan (as C. incertipenis), Thailand (as Chironomus sp.).
Given the wide distribution, it is not surprising that there are variations in coloration.

Previously called C. species PK2 and PK7. Also C. apicatus sensu Karunakaran (1969) but the Johannsen description is insufficient to clearly associate his specimens with this species as they have a higher LR and are associated with occurrence in warm, acidic pools, so they are probably another member of the C. flaviplumus-group. The ÒC. ramosusÓ of Laviad-Shirit et al. (2020) and Sela et al. (2021) are this species and do not fit the original description of C. ramosus Chaudhuri et al. (1992), which has a higher AR and a lower LR (see below).

The species is in BOLD Bin: BOLD:AAW3997

Adult

Male:
AR 2.91 (2.85-3.05), LR 1.65 (1.59-1.75).
Wing length 3.46 (2.82-3.86) mm., width 0.77 (0.68-0.88) mm., VR 0.97 (0.95-1.0); squamal fringe 20.7 (12-27); SCf on brachiolum 2-3.
Head: Frontal tubercles 38.9 (15-51) x 13.3 (10-18) µm (l/w 1.15-4.3); palpal proportions (µm) 52 (48-55) : 55 (50-60) : 211 (200-240) : 224 (205-235) : 323 (265-371); P5/P4 1.43-1.61; P5/P3 1.39-1.81. Clypeus, width 0.61 (0.53-0.63) diameter of antennal pedicel, with 21.9 (19-24) setae.
Thoracic setae: acrostichal about 11.7 (10-15) in double staggered row; dorsocentral about 18.3 (14-26) in one to three rows; prealar 5.5 (5-6); scutellar in two to three rows, anterior row of 10.5 (8-12) smaller setae, sometimes with abt 2 in a further anterior row, posterior row of 13 (11-15) larger setae (total setae 21-28).
Legs yellowish, becoming darker on the tarsi. Foretarsus without a beard (BR 1.35-2.2).
Lengths (micron) and proportions:

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	Ta5/Ti
PI	1237	1140	1805	962	825	735	350	1.59-1.75	1.02-1.20	0.24-0.35
PII	1338	1187	734	402	292	187	139	0.58-0.69	1.06-1.17
PIII	1520	1482	1100	610	457	286	169	0.64-0.83	1.00-1.06

BR 1.35-2.2; Sensilla chaetica: Mid Ta1 - 6-10; Hind Ta1 - 5-9.

Abdomen with dark oval markings on tergites III-V or VI, with others light brown. About 13 (5-19) setae in multiple pale areas on TIX.

Male hypopygium and superior volsella of C. flaviplumus Type B
Note that the anal point is not dark and the Superior volsella is strongly bent and "beaked"

Superior volsella beaked and not easily fitted into the scheme of Strenzke (1959), but essentially S-type. Inferior volsella not reaching to end of anal point but to about 1/3 of gonostylus length, with simple setae.
The anal point narrow at base and does not appear to be darkened or sharply downturned. Gonostylus moderately swollen and narrows markedly over about posterior third to half, with 5, 5+1 or 6+1 setae at the tip..

Female:
Some information for antenna from a pupa, and for genitalia from a pharate female: Antennal segments 2-5 (proportion of neck in brackets) Ð 105 (0.33) : 135 (0.65) : 130 (0.46) : 200; AR and seg. V/I not known TX about 1.67x longer than greatest width, with 14 setae; cercus with straight dorsal margin coming to a curved posterior transition to posterior margin, which merges to curved ventral margin.

Genital region of pharate female

It is not obvious that this species is conspecific with C. incertipenis as suggested by entries in the BOLD Bin. The two species are similar in many aspects and the comparison of the adult of C. incertipenis to C. yoshimatsui is consistent with it being a member of the "flaviplumus-group".
Many of the distinguishing features of C. incertipenis in the original description as C. niger are typical of the group, and consistent with those of this species, but two adult characters of C. incertipenis suggest it is distinct from the present species: 1. the anal point of the adult male is dark brown and sharply downturned, cf. the more usual yellow brown of C. ramosus and 2. the Superior Volsella of C. incertipenis is described as gently curved while that of the present species is strongly curved and beaked. However, the type of C. incertipenis should be re-examined to confirm the accuracy of the original description as it is possible that its hypopygium is distorted.

Found: India - Jammu & Kashmir: Kabeer colony, Jammu; Deoli Village; Farooq Nagar (abt. 28.30°N,76.80°E), Jammu; Kabeer colony
(32.70°N, 75.00°E), Jammu; Bishnah wetlands;
Gadhigargh (33.00°N, 74.92°E); Sangrampur village; Univ. Jammu & Kashmir (32.73°N, 74.87°E), Jammu.
Japan - Kyushu: Nabikimatsu (33.60°N, 130.33°E), Koge-Machi,Chikujyo-gun, Fukuoka Pref.;
Ryukyu: Mt Omotodake, Ishigaki Cty, Ishigaki Island, Yaeyama Islands, Okinawa Prefecture.
Malaysia - University of Malaya, Selangor (3.1295°N, 101.657°E) (BOLD)
Pakistan - Islamabad (33.6863°N, 73.0763°E) (BOLD)
Singapore - Bedok Canal (1.367°N, 103.939°E).
Thailand - Mahasarakham University, Kantharawichai District, Maha Sarakham Province (14.85°N, 103.26°E); Ban Tha Reu, Satuek
District, Buri Ram Province (15.33°N, 103.56°E); Ban Keab, Kantharawichai District, Maha Sarakham Province (16.26°N, 103.22°E);
Ban Khi, Chiang Yuen District, Maha Sarakham Province (16.27°N, 103.23°E).
Also:
Israel - Mt. Hermon (33.40°N, 35.85°E).
It includes some of those Indian samples (besides C. indiaensis) that have been classed as "C. samoensis" or "C. nr. samoensis".

DNA Sequence:
MtCOI: A sequence from Japan and several from India are in the BOLD database.
The sequence indicates that this species is quite close to the European and Asian C. alpestris, Goetgh.

[ Return to Index | Go to C. flaviplumus Ty.B immatures & cytology | Go to C. flaviplumus | See C. incertipenis | See C. ramosus ]