Chironomus claggi Tokunaga 1964

Syn: Chironomus simantobeceus Sasa, Sukuki and Sakai 1998 (Yamamoto et al. 2018).

In BOLD Bin: BOLD:ACQ6925.


(based on Tokunaga (1964).

Large yellow and dark brown or brown species.

Body length 5.33 (5.01-5.66) mm, Wing length 2.67-2.69 mm; width 0.68-0.72 mm., crossvein not darkened, VR about 1.
Frontal tubercles cylindrical about the length of 2 eye facets.  Palps brown, segment lengths: 15.5 : 16.5 : 70.5 : 70.5 : 84; P5/P4 & P5/P3 1.19; AR 2.7 (2.5-2.85).
Thorax widely yellow, vittae entirely yellow, scutum white. 9-11 small setae in anterior row and 10-11 larger setae in posterior row (total 19-22) on scutellum.
Legs with coxae and trochanters usually yellow, all femurs mainly yellow but apically brownish, fore tibia mainly dark but other tibiae dark only on basal parts; fore tarsi entirely black or dark brown, other tarsal segments pale or yellowish brown on basal 1 or 2 segments but apical part black or more brownish as on following segments; LR 1.7 (1.66-1.77); Fe1/Ti1 1.22.
Abdomen mainly very pale brown, but TII-VI with basal bands brown and broad, other segments uniformly brown.  TIX with about 8 setae in a pale area.

Hypopygium and superior volsella of C. claggi from Tokunaga 1964

Superior volsella of the dorsalis-type, closest to S-type of Strenzke (1959), similar to that of C. indiaensis.  Inferior volsella long, to half way along gonostylus, setae bi- or trifurcate apically; gonostylus moderately swollen and reduces gradually over posterior third.  Anal point narrowed at base.

Superior volsella a boot shape closest to S-type of Strenzke (1959), similar to that of C. indiaensis.  Setae of inferior volsella bi- or trifurcate apically.

Female: Wing length 3.04 mm, width 0.89 mm.  LR about 1.81.  Frontal tubercles about 1.5 times as long as the diameter; palp proportions about 20 : 18 : 70.5 : 82.5 : 107; P5/P4 1.30, P5/P3 1.52.
Scutal vittae entirely brown; scutellum with 12 setae along caudal margin and 7-10 smaller setae anteriorly (total 19-22).
Abdomen mainly yellow with dark tergal bands on all but last two segments which are dark brown.

Pupa: It is not clear whether this known pupa is definitely associated with this species.  It was collected along with a female, but there is no detail as to how they were associated - the caudo-lateral spur is rather unusual for a Chironomus species, more like that of a Stictochironomus, as is a "rounded" anal swim fin.  With that proviso, Tokunaga's description gives the following information:
Length about 7 mm.  Cephalic tubercles small on a basal blunt swelling and with a small lateral seta.  Abdominal surface very weakly spinulous, sternite IV with lateral groups of spinules hardly visible; tergite II with about 71 yellow simple hooklets; caudolateral spur black with 5-6 lateral and 3-5 apical spines.

Pupal cephalic tubercles and spur of C. claggi from Tokunaga 1964

Larva and Cytology: Not known.

Found: Type localities - Futami-ko; Camp Beach, Omura; Gen's beach, Minato-ko, Yatsue Region; all Chichi Jima, Micronesia.
            Japan - Tokyo Metropolitan; Chicijima Island, and Hahajima Is., Bonin Isles, Tokyo; Shimanto River, Nakamura, Kochi Pref. (type locality of C. simantobeceus) (all Yamamoto & Yamamoto, 2018); and Ogasawara, Kanto (GenBank & BOLD).

According to Yamamoto & Yamamoto (2018), C. claggi superficially resembles C. flaviplumus and C. yoshimatsui but is separable by the more slender superior volsella.  In scutal coloration and superior vollsella shape it resembles C. circumdatus.

DNA Sequence:
The mtCO1 sequence for Japan in GenBank is AB740233-34.

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Created: 3 March 2023
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