Polypedilum (Collartomyia) longiligulatum (Cheng & Han & Cranston, 2018)

Cheng, Hongqu Tang Qingqing, Han, Wu & Cranston, Peter S., 2022, Integrative taxonomy: molecular phylogenetics of Polypedilum (Cerobregma) and revisited morphology of Yaethauma and Collartomyia (Diptera: Chironomidae) reveals synonymy and supports new classification, Zoological Journal of the Linnean Society 194, pp. 102-119 : 111

POLYPEDILUM (COLLARTOMYIA) LONGILIGULATUM (YAMAMOTO ET AL.) COMB. NOV.

Yaethauma longiligulatum Yamamoto et al., 2018: 45 .

Material examined: ( CHINA, all collected by H.Q. Tang unless otherwise stated). Paratype ♂, Hainan Province, Changjiang County, Bawangling National Nature Reserve, stream across unnamed cement road to field station of Nancha River , 19°07’N 109°12’E, 650 m a.s.l., 17.iv.2016, light trap; as previous except hand-net interception; 7 Pe, Ledong County , Jianfengling National Nature Reserve , 18°04’N, 108°53’E, 632 m a.s.l., 29–30.iv.2012; Pe, Lingshui County , Diaoluo National Nature Reserve , 18°47’N 109°55’E, 250 m a.s.l., 30–31.viii.2013; Pe, Guangdong Province, Yingde City, Xiucai Mt. , xi.2018, C.B. Duan, ♂ Zhejiang Province, Xianju County , Danshui Country, Shimengyang village , Yong’an stream, 28°40’N 120°35’E, 145 m a.s.l., 10.xi.2019, light trap; Pe, as previous except hand-net. Male (N = 2) ( Fig. 3A–C ) .

Colour: Generally dark brown. Gonocoxite and apicolateral bulb-like extension brown or dark brown ( Fig. 3B ). Gonostylus pale yellow. Wing with brown cross-vei, legs banded as Fig. 3A, C .

Wing length 1.8–2.2 mm: AR 0.61–0.71, last segment 400–460 µm. 1.39–1.47. Gonocoxite with welldeveloped apicolateral bulb. Gonostylus slender, with stout apex. Inner margin of gonostylus and apex of inferior volsella with split setae. True median volsella absent. Other details, and female, see Yamamoto et al. (2018). Pupa (N = 10). Abdomen length 3.0–3.9, 3.5 mm, total length 4.3–5.4, 4.9 mm. Exuviae dark brown with distinct brown apophyses. Cephalothorax ( Figs 3D–F , 4A ). Cephalic tubercle and frontal seta ( Fig. 4A ) absent. Thorax smooth along the suture, with distinct anterior-directed tapering projection ( Figs 3D, E , 4B ), 85–140 µm high, 80–120 µm wide at base. Antepronotals present, two precorneals 50–70 µm and 25–30 µm long. Lengths of dorsocentrals 1–4 (µm, N = 1): 25, 20, 40, 20. Gap between Dc2 and Dc3 210–275 µm. Tracheal bundle simple, slender; basal ring elliptical, with five to seven branches ( Figs 3F , 4C ). Prealar tubercle absent, wing sheath ( Fig. 4B ) without nose or pearl rows. Abdomen ( Figs 3D , 4D ). Tergal spinules uniform-sized, without distinct transverse bands, with more extensive and even tergal spinulation, almost covering complete TII–VII, TVIII with two small median patches; conjunctives bare in all segments. Sternites with dense honeycomb reticulations in most segments except SI, cells of reticulation with small spinules; paired tubercles on posterior of segment VIII only in female. TII with a row of c.150–200 caudal hooklets, less-sclerotized, tightly packed, extending 45–57% of segment width. Pedes spur A (vortex) and B absent. Lateral setae on segment I–VIII 1, 2, 2, 2, 2, 2, 2, 4, taeniate only on VIII ( Fig. 4D ). Comb VIII 150–210 µm high and 70–90 µm wide, with dominant larger inner tooth and 8–12 small teeth laterad ( Fig. 4E ). Anal lobe 500–550 µm wide and 330– 420 µm high, with c.168–250 multiserial taeniae. Male genital sac overreaches lobe margin by 70–80 µm.

Distribution: China (Hainan, Guangdong, Zhejiang), Japan (Iriomote Is.) and Thailand (Chiang Mai).

Remarks: Additional records extend the previous distribution of this species (under ‘ Yaethauma ’) from the subtropics southwards to the true tropics, implying a wide geographic range. The newly described pupa here can be regarded as an atypical form in an expanded subgenus Collartomyia , since the characteristic cone-like cephalic tubercle and frontal seta are completely reduced and the lateral taeniate setae are restricted only to segment VIII. However, those features exist also in P. (Coll.) hirsutum ( Amakye & Saether, 1992) comb. nov. (see below).

Figures

Figure 3. Polypedilum (Collartomyia) longiligulatum. Colour images. Male. A, habitus, dorsal; B, hypopygium, dorsal view (Gc bulb, gonocoxite bulb; Gs, gonostylus); C, habitus, lateral. Pupa: D, habitus, dorsal; E, cephalothorax, lateral; F, thoracic horn, lateral. (Scale bars: A, C, D, E 400 µm; B, F,100 µm.)

Figure 4. Polypedilum (Collartomyia) longiligulatum. Pupa. A, frontal apotome; B, thorax; C, thorax horn; D, abdomen; E, caudolateral comb of segment VIII. (Scale bars. A, E, 100 µm; B, 400 µm; C, 20 µm; D, 200 µm.)