A review of the genus Rheotanytarsus Thienemann & Bause from China (Diptera: Chironomidae: Tanytarsini)
Author
Wang, Xinhua
Author
Guo, Yuhong
text
Zootaxa
2004
650
1
19
journal article
10.5281/zenodo.158146
7d9a2a09-d143-438c-a4ac-a4488ef61251
11755326
158146
9E918826-9476-4A0E-9528-ABAC9911BA6C
Rheotanytarsus aphelus
sp. n.
(
Figs. 1–3
)
Type
material.
Holotype
male (BDN No. 07015),
China
,
Tianjin
City, Ji County, Yuqiao Reservoir.
X. 17. 1987
. Leg. X. Wang, sweep net.
Etymology.
From Latin
apheles
, smoothness, simple, referring to the smooth superior volsella.
Diagnosis.
The species differs from other members of the
acerbus
group by having well developed oral projections of the transverse sternapodeme, more numerous acrostichals, and fewer setae anterior to the anal point.
Male imago
(n=1)
Total length
3.40 mm
. Wing length
1.90 mm
. Total length / wing length 1.79. Wing length / profemur length 2.02. Coloration brown, eyes black.
Head.
Antenna with 13 flagellomeres. AR 0.97, ultimate flagellomere 528 µm long. Temporal setae consisting of 8 inner, 4 outer verticals and 4 postorbitals. Clypeus with 18 setae. Tentorium 140 µm long, width 30 µm. Palpomere lengths (in µm): 40; 52; 134; 144; 224.
Wing
(
Fig. 1
). VR 1.42, Cu 840 µm long.
Thorax.
Acrostichals 26; dorsocentrals 9; prealars 1. Scutellum with 8 setae.
FIGURES 1–5. Figs. 1–3.
Rheotanytarsus aphelus
sp. n.
Holotype, male imago: 1. Wing, 2. Hypopygium, 3. Median volsella.
Figs. 4–5.
Rheotanytarsus bullus
sp. n.
Holotype, male imago: 4. Wing, 5. Hypopygium
Legs.
Spur of front tibia 30 µm. Spurs of middle tibia 40 and 32 µm long, of hind tibia 48 and 44 µm long. Combs of middle leg composed of 18 and 14 free teeth, hind leg of 18 and 16 free teeth. Lengths and proportion of legs (Table 1):
|
TABLE
|
1.
Rheotanytarsus aphelus
sp. n.
|
Lengths of legs |
(in |
µm). |
| fe ti ta1 ta2 |
ta3 ta4 |
ta5 |
LR |
| P1 |
940 480 1060 496 |
392 320 |
144 |
2.21 |
| P2 |
900 664 416 280 |
144 96 |
80 |
0.63 |
| P3 |
1040 832 664 360 |
288 184 |
104 |
0.80 |
Hypopygium
(
Figs. 2–3
). Anal tergite bands V
type
, widely separated medially, extending almost to base of anal point. Tergite IX with 8 setae. Anal point tapering gradually to rounded point. Crests well developed, subparallel. Phallapodeme 70 µm long. Transverse sternapodeme 60 µm long, straight, with pointed oral projections. Gonocoxite 140 µm long. Superior volsella 46µm long, rectangular on left side, oval on right, with 2 inner and 7–8 dorsal setae, 1 long seta on ventral surface near middle. Digitus absent. Inferior volsella 89 µm long. Median volsella (
Fig. 3
) 66µm long, lamellae on about 35–40 µm long stem. Gonostylus abruptly narrowed in apical 1/2, recurved, 140 µm long. HR 1.00; HV 2.43.
Distribution.
The species is known from Yuqiao Reservoir, a typical mesotrophic water body in
Tianjin
(Palaearctic
China
).