Microtendipes parachloris Niitsuma & Tang, 2017

Niitsuma, Hiromi, 2017, Review of the Japanese Microtendipes tera: Chironomidae: Chironominae), with description of a new species, Zootaxa 4320 (3), pp. 535-553 : 548-550

Microtendipes parachloris Niitsuma & Tang sp. nov.

( Figure 4 )

Microtendipes chloris [nec Meigen, 1818: 28]: Sasa 1984: 56; Sasa & Kamimura 1987: 16.

Type material. Holotype: M ( NSMT), labelled, “No. 101: 81”, JAPAN: Hokkaido, Lake Akan , 17.vi.1982 . Paratype: M ( NSMT), labelled, “No. 39: 86, 87”, JAPAN: Tochigi, Nikko, Lake Yunoko , 28.iv.1979 (emerged 26.v.1979) .

Derivatio nominis. From Greek para -, a prefix meaning near, like, and the name of Microtendipes chloris (Meigen) , referring to the morphological similarity of the male adults of both the species.

Description. Male (n = 2). Total length 5.3–5.8 mm.

Coloration. Thorax entirely dark brown; scutal vittae indistinct. Abdomen largely pale yellow; tergite I darkened anteriorly, tergites II–V each with vertically long and dark marking anteromedially ( Figure 4A ), tergites VI–IX darkened entirely; hypopygium dark brown on gonocoxite and gonostylus. Wing without any marking on membrane. Foreleg brown with apical 0.10–0.11 of femur dark brown; tibia and ta1 uniformly dark brown. Mid and hind legs brown, each with femur and tibia somewhat darker.

Head. Temporals 17–22. AR 2.5–2.7. Clypeus with 24–29 setae. Lengths (µm) of palpomeres 1–5: 60–75, 75– 90, 245–310, 260–310, 360–450, respectively. Pm4/Pm3 1.0–1.1; Pm5/Pm4 1.4–1.5. Pm3 with 3 sensilla clavata, longest 25 µm long.

Thorax. Antepronotum with 3–4 lateral setae. Acrostichals 4–7; dorsocentrals 9–15, uniserial; prealars 4–5, uniserial. Scutellum with 26–27 setae.

Wing. Length from arculus to apex 3.9–4.1 mm. Veins R, R1 and R4+5 with 24–25, 22–28, 38–43 setae, respectively. VR 1.1. Squama broken off.

Legs. Forefemur externally with 2 rows of 20–28 setae directed basally on distal half; foretarsus without long setae. Mid ta1 with 7–9 sensilla chaetica, distalmost located 0.43–0.45 from base. Lengths and proportions of legs as in Table 4.

Hypopygium ( Figure 4B ). Anal tergite with 2–8 median setae on each end of tergal bands; posterior tergal margin with 18–21 setae on each side. Anal point ( Figure 4C ) nearly parallel-sided with truncate apex. Superior volsella ( Figure 4D ) sickle-shaped, pointed at apex, with one basal and 7–8 dorsolateral setae. Median volsella poorly developed, with 2–3 clustered setae; tubercle indistinct. Inferior volsella reaching beyond tip of gonocoxite, stout, with many recurved dorsal setae on distal 2/3. Transverse sternapodeme broad.

Female, pupa and larva. Unknown.

Remarks. Sasa (1984) recorded a single male under the name of M. chloris ( Meigen, 1818) from Lake Yunoko in Tochigi, central Japan. The same name was also assigned to the male collected from Lake Akan in Hokkaido, northern Japan, by Sasa & Kamimura (1987).

Indeed, the male is very similar to that of M. chloris in the hypopygial structure: anal point parallel-sided; superior volsella sickle-shaped with a basal and several dorsolateral setae; and inferior volsella long, reaching beyond the apex of the gonocoxite. For the same reason, the male resembles that of M. pedellus ( De Geer, 1776) , too. However, the male will not key past couplet 8 in the Langton & Pinder (2007: 177) because of the uniformly darkened foretibia and the foretarsus without long setae, and differs from the males of these two species in the poorly developed median volsella, only bearing a few setae, in the hypopygium. The males of M. pedellus and M. chloris are armed with distinct tubercles of the median volsella bearing several setae ( Langton & Pinder 2007: 110, fig. 219 C, D).

The male somewhat resembles that of M. umbrosus in the hypopygium with a parallel-sided anal point, sickleshaped superior volsellae, and poorly developed median volsellae, but differs from it in the relatively high value of AR 2.5–2.7, the wings without any marking, and the entirely dark brown basitarsus of the foreleg. The male of M. umbrosus has a low value of AR 1.7–2.1, a cloud on the wing membrane, and a basitarsus darkened at most basally in the foreleg.

Figures

FIGURE 4. Microtendipes parachloris Niitsuma & Tang sp. nov., holotype male, NSMT No. 101: 81 (A, B) and paratype male, NSMT No. 39: 87 (C, D). A, Abdominal tergites III – IV, dorsal view, showing marking pattern; B, hypopygium, dorsal view; C, anal point, dorsal view; D, superior volsella and median volsella, dorsal view.