Psectrocladius nevalis Akhrorov, 1977

Ge, Xinyu, Wang, Chengyan, Pei, Wenxuan, Tang, Yaning, Liu, Wenbin & Yan, Chuncai, 2024, New descriptions of the larval and pupal stages of Orthocladius nitidoscutellatus and Psectrocladius nevalis from Xizang, China (Diptera, Chironomidae), Biodiversity Data Journal 12, pp. 121952-121952 : 121952

Psectrocladius nevalis Akhrorov, 1977

Psectrocladius nevalis Psectrocladius nevalis Akhrorov, 1977 - Akhrorov (1977): 14; Ashe and O'Connor (2012): 516

Materials

Type status: Other material. Occurrence: lifeStage: 2 Larvae I 1 Pupa; occurrenceID: 9B86C70A-908A-5E53-B595-F6F14D98C454; Location: country: China; stateProvince: Xizang Autonomous Region ; locality: Naqu City , Sena District , Naqu Bridge on the Naqu River ; verbatimLatitude: 31°42.78′N; verbatimLongitude: 91°98.82′E; Event : eventDate: 7 Jul 2022; Record Level: institutionCode: Tianjin Normal University, Tianjin, China (TJNU)

Description

Pupa (n = 1).

Cephalothorax (Fig. 3 C-D, Fig. 4 C-D). Cephalic tubercles present, frontal setae 58 μm long. Thoracic horn elongate, 290.50 μm long, 42.10 μm wide. Thorax smooth, free of tubercles. Wing sheath without protrusions. Next to the thoracic horn, three precorneal setae are present, lengths of precorneals (µm): 60.20, 125.15, 135.00. 4 dorsocentral setae, the first three are almost evenly spaced, while the fourth one is slightly further away, lengths of dorsocentrals (µm): 50.20, 60.10, 75.15, 76.20.

Abdomen (Fig. 3 A-B, Fig. 4 E-F). Sternite I bare; Sternites II-VIII with sparse shagreen; anterior row of anal lobe with shagreen. Sternites II-VIII with posterior row of small spines. Pedes spurii A present in segment III-IV. Pedes spurii B present on segment II. tergites II-VI with 3 Lt-setae; tergite VII with 4 Lt-setae. tergite VIII with 7 Lt-setae. Anal lobe 565.50 µm long and 586.05 µm wide, with 5 subequal anal macrosetae and 20-23 setae in fringe. Anal lobe genital sheath 462.80 µm long, not extending anal lobe.

Fourth instar larva (n = 2).

Head capsule (Fig. 3 H) length / width: 525.24- 550.30 µm / 353.45-380.00 µm: 1.45-1.49.

Colouration. The apical 1/3 of mandible, mentum and posterior occipital margin dark brown; the remaining area of head capsule brown.

Antenna (Fig. 3 F and B) with 5 segments, each segment length (μm): 80.31-90.40, 18.25-20.00, 11.42-14.10, 6.50-8.00, 2.10-3.22. Antennal ratio 1.99-2.09. Basal segment almost as long as wide. The distance from base to ring organ 18.87-21.15 µm. Premandible 51.88 μm- 60.10 μm long, terminating in a single tooth. Mandible (Fig. 3 G, Fig. 4 A) 95.22-101.94 μm long, with 1 apical and 3 inner teeth; apical tooth 24.60-30.72 μm long, nearly equal to the 3 inner teeth in the width. Mentum (Fig. 3 E, Fig. 4 A) with 2 median teeth and 4 pairs of lateral teeth, 145.11-156.32 μm wide; a single median tooth almost 2 times larger than the first lateral tooth; postmentum 328.90-350.00 μm long; the distance between the setae submenti 93.75-100.10 μm.

Figures

Figure 3. Psectrocladius nevalis Akhrorov, 1977. A pharate adult with pupae Chironomidae exuviae; B sternites VIII-IX; C thoracic horn; D wing sheath; E mentum; G mandible; H larval head shell.

Figure 4. Psectrocladius nevalis Akhrorov, 1977. A mentum; B antenna; C frontal apotome; D thoracic horn; E sternites VIII-IX; F segment I-VII.