Paratanytarsus nanyuensis, Li & Tang, 2021

Li, Zhiqiang & Tang, Hongqu, 2021, Two new species of Paratanytarsus Thienemann & Bause (Diptera: Chironomidae) from Oriental China, Zootaxa 4903 (3), pp. 430-438 : 431-434

Paratanytarsus nanyuensis sp. n.

( Figs. 1–2 )

http://zoobank.org/ urn:lsid:zoobank.org:act:A10B4AC8-C204-4BBC-B1E6-797CF530F5CA

Type material. Holotype: adult male, CHINA: Guangdong Province, Guangzhou City, Huangpo District, Huangma villa, 23°13′N, 113°27′E, alt. 80 m, 14.xii.2018, H.Q. Tang . Paratypes: 1 adult male, as holotype except 27.x.2019, H.Q. Tang; 1 pharate male, 2 pupal exuviae, Guangdong Province, Guangzhou City, Dongkeng Reservoir , 23°45′N, 113°48′E, alt. 362 m, 26.viii.2014, J. Liu ; 1 adult male, Guangdong Province, Shantou City, Nan’ao County, Yun’ao Reservoir , 23°26′N, 117°06′E, alt. 234 m, 17.iii.2015, H.Q. Tang; 2 pupal exuviae, Macao SAR, Hac-Sa Reservoir, 22°08′N, 113°34′E, alt. 100 m, 11.xi.2014, Z.Q. Li .

Derivatio nominis. From the name of old kingdom in South China, ‘ nan-yue’, referring to the type locality.

Diagnosis. Adult male. Anal tergite bands fused into a sclerotized quadrate hump on base of anal point. Anal point angular basally, and anal crests fused into a circle. Pupa. Thoracic horn, wing pearl row and A VIII comb teeth absent; T III with paired, semicircular patches of spines in posterior half, T IV–V with paired, anterior patches of points, without additional patches laterally.

Description. Male (n = 3). Total length 2.3–2.7, 2.5 mm. Wing length 1.2–1.4, 1.3 mm.

Coloration. Body predominantly yellow; thorax slightly darkened on scutal vittae, anepisternum II, preepisternum and postnotum; abdomen with T VI–VIII light brown. Wing with yellowish green undertone. Legs with brown subapices of femora and tibiae.

Head. Temporals 7–8, 8. Antenna with 13 distinct flagellomeres; terminal flagellomere 400–500, 436 μm long, with distal seta 60–70, 64 μm long; AR 1.00–1.12, 1.06. Frontal tubercle minute, conical, 7–10, 8 μm long, and 4–6, 5 μm wide. Lengths of palpomeres 2–5 (μm): 25–30, 27; 35–40, 37; 80–95, 88; 95–110, 102; 170–190, 182. Clypeus with 20–26, 24 setae.

Thorax. Aps absent. Ac 15–18 (2), biserial; Dc 7–12 (2); H 2–3 (2); Pa 1–2 (2); Scts 3–5. Scutal tubercle large, 6–10, 8 μm high.

Wing. VR 1.13–1.16 (2).

Legs. Foretibia with straight spur 15–20 (2) μm long. Mid and hind tibiae with 2 combs separated, each bearing spur; spur straight or slightly curved, 20–30 (2) μm long on mid tibia and 27–35 (2) μm long on hind tibia. Ratios of leg segments: LR 1 1.94–2.19 (2), BV 1 1.48–1.55 (2), SV 1 1.31–1.40 (2); LR 2 0.65–0.67, 0.66, BV 2 4.18–4.25, 4.21, SV 2 3.63–3.79, 3.69; LR 3 0.68–0.75, 0.71, BV 3 2.44–2.58, 2.51, SV 3 2.93–3.23, 3.08.

Hypopygium ( Fig. 1 ). T IX ( Fig. 1A ) microtrichiose, with lateral teeth on posterior margin; anal tergal bands V-shaped, extending posteriorly and ending with paler quadrate hump bearing strong lateral seta on each side. Anal point ( Fig. 1B ) apically rounded, basally angular with lateral projections. Anal crests short, fused, forming a circular structure. Gonocoxite 88–105 (2) μm long. Superior volsella subtriangular, with 2 setae on dorsal surface and 4 setae on inner margin, without microtrichia; digitus ( Fig. 1C ) elongate, slightly curved caudally, extending beyond inner margin of superior volsella, with rounded apex. Median volsella ( Fig. 1D ) with many setiform lamellae along inner margin and slender spindle-shaped lamellae on apex, extending beyond distal tip of inferior volsella; stem 55–75 (2) μm long, somewhat curved and directed posteriorly. Inferior volsella ( Fig. 1E ) apically swollen, bearing ca. 20 strong setae, basally with dorsal swelling. Gonostylus 108–138, 123 μm long, 4.6–5.3, 5.0 times as long as broad at middle; HR 0.73–0.80, 0.77.

Pupa (n = 4). Total length 2.6–3.4, 3.0 mm.

Coloration. Body pale yellow with brown T VIII–IX.

Cephalothorax. Frontal apotome ( Fig. 2A ) with 2 setae 60–70, 64 μm long, slightly longer than distance be- tween these setae; cephalic tubercle absent. Thoracic horn absent. Antepronotal 1; precorneals 3, including 1 strong seta well separated from 2 small setae. Dc 1 simple, 25–55, 35 μm long; Dc 2–4 multibranched. Prealar tubercle indistinct or absent ( Fig. 2B ). Wing sheath with distinct nose, pearl row absent.

Abdomen ( Fig. 2C ). T I, VI–VII without spinulation; II with extensive spinulation patches consisting of anterior transverse band of points and paired longitudinal bands of spinules; III with paired, vertically elongated patches of spinules and paired, semicircular, posterior patches of 35–45, 40 spines, 55–65, 60 μm long; IV–V, VIII with paired anterior patches of points; IX with anterior patch of spinules. T II with rows of 80–85, 83 caudal hooklets; its row 160–185, 175 µm long, 0.53–0.56, 0.54 times as long as segment width. Pedes spurii A absent, pedes spurii B distinct on A II. Anal comb on A VIII completely absent. Number of Lt-setae on A IV–VIII: 1, 3, 4, 4, 5, respectively. Anal lobe 160–205, 182 μm long, anal lobe ratio 1.52–1.71, 1.63, with one dorsal seta and 22–30, 26 lateral taeniae; male genital sac 50–57, 55 μm long, extending beyond lobe.

Female and larva. Unknown.

Discussion. The adult male of Paratanytarsus nanyuensis sp. n. will key to the penicillatus group in Cranston et al. (1989), whereas the pupa will key to the tenellulus group in Pinder & Reiss (1986).

In the penicillatus group defined by Pinder & Reiss (1986), the male most resembles that of P. penicillatus (Goetghebuer) in having a peculiar hump on the anal tergite but differs in the structure of anal tergal hump and the shape of anal point. In the male of P. nanyuensis sp. n., both the distal ends of anal tergal bands are fused into one quadrate hump with a few lateral setae, and the anal point is basally angular because of the lateral projections. In the latter, however, the hump is located near the middle of each tergal band and bears several setae, and the anal point lacks basolateral projections ( Reiss & Säwedal 1981, fig. 11). These features of P. nanyuensis sp. n. are unique in this genus.

The pupa is somewhat similar to that of P. tenellulus (Goetghebuer) in the abdominal spinulation, but may be separable by the semicircular posterior spine patches on T III and the anterior point patches interrupted medially on T IV–V. In the latter, the posterior spine patches on T III are curved and the anterior point patches on T IV–V are transversely continuous ( Säwedal & Langton 1977, fig. 3; Reiss & Säwedal 1981, fig. 23; Langton & Visser 2003, fig. 131c). Further, the pupa differs from the latter in the absences of thoracic horns and combs on the abdominal segment VIII. The latter has well-developed thoracic horns and weak combs on the segment VIII ( Langton & Visser 2003, fig. 131b, d).

Biology and ecology. All the specimens examined were collected from stagnant water bodies, such as reservoirs, ponds or temporary pools in streams. Water temperature ranges from 10.5℃ to 28.8℃, and dissolved oxygen from 3.6 mg /l to 6.9 mg /l. The adults apparently occur all through a year.

Figures

FIGURE 1. Paratanytarus nanyuensis sp. n., male. A, Hypopygium, dorsal view; B, anal tergite with anal point; C, superior volsella; D, median volsella; E, inferior volsella. Scale: A, D, 50 µm; B, C, E, 25 µm.

FIGURE 2. Paratanytarus nanyuensis sp. n., pupa. A, Frontal apodome; B, cephalothorax, lateral view; C, abdomen, dorsal view. Scale: A, 100 µm; B–C, 50 µm.