Hydrosmittia spinata, Zhang, Ruilei, Liu, Wenbin, Ferrington, Leonard C. & Wang, Xinhua, 2016

Zhang, Ruilei, Liu, Wenbin, Ferrington, Leonard C. & Wang, Xinhua, 2016, Two new species of genus Hydrosmittia Ferrington & Saether (Diptera: Chironomidae) from China, Zootaxa 4121 (2), pp. 167-174 : 171-172

Hydrosmittia spinata sp. n.

( Figure 2 )

Type material. Holotype male (BDN No. 04690), China, Sichuan Province, Mt. Emei, 3077m, 18. V. 1996, Sweep net, X. Wang.

Etymology. From Latin spina, thorn, referring to the virga consisting of sclerotized mace-liked structure bearing thorn-like spinules.

Diagnostic characters. The low AR about 0.23 combined with the low inferior volsella, the lateral thorn-like spinules of the virga apparently occurring on a sclerotized mace-like structure, and a developed heel on gonostylus will separate the male imago from other species of the genus.

Male imago (n = 1)

Total length 2.11 mm. Wing length 1.45 mm. Total length/wing length 1.45. Wing length/ length of profemur 3.15.

Coloration dark brown with abdominal segments I to IV light brown.

Head. AR 0.23. Temporal setae 7, including 1 inner vertical, 2 outer verticals and 4 postorbitals. Clypeus with 4 setae. Cibarial pump, tentorium and stipes as in Fig. 2A . Tentorium 128 µm long; stipes slender, 83 µm long. Palpomere lengths (in µm): 20, 55, 88, 85, 105. Length of 5th palpomere/ 3rd palpomere 1.23. The 3rd palpomere with 1 lanceolate sensillum clavatum.

Thora x. Median antepronotal lobes well developed, antepronotum with 1 lateral seta. Acrostichals 2, dorsocentrals 6, prealars 3. Scutellum with 5 setae.

Wing ( Fig. 2B ). VR 1.39. Anal lobe well developed, more or less projecting. Costal extension 175 µm long. R4+5 ending slightly distal to apex of M3+4, Cu1 sinuate. Brachiolum with 1 seta, R with 1 basal seta, R4+5 with 1 apical seta, other veins bare.

Legs. Spur of front tibia 28 µm long, spurs of middle tibia 20 µm long and 19 µm long, of hind tibia 33 µm and 15 µm long. Width at apex of front tibia 25 µm, of middle tibia 25 µm, of hind tibia 38 µm. Comb of 10–14 setae, shortest seta 13 µm long, longest seta 26 µm long. Lengths and proportions of legs as in Table 3.

Fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR P1 460 610

P2 570 580

P3 550 600 300 0.50 3.83 Hypopygium ( Fig. 2C–E ). Anal point 18 µm long, with microtrichia at base, bare apically; tergite IX with 14 setae; laterosternite IX with 3 setae. Phallapodeme 60 µm long; transverse sternapodeme 85 µm long, with well developed oral projections. Virga consisting of 35 µm long sclerotized mace-like structure ( Fig. 2C ) bearing 9 thorn-like spinules and 18 µm long ventral median spine ( Fig. 2D ). Gonocoxite 168 µm long; inferior volsella low, right-angled; accessory lobe weak, reaching to 0.58 and 0.75 gonocoxite length, respectively. Gonostylus 65 µm long, broadened gradually from base, with more or less pronounced outer heel; megaseta 10 µm long. HR 2.58, HV 3.24.

Distribution. Sichuan Province (Oriental China).

Remarks. The species was collected on the top of Mt. Emei at an altitude of 3077m. The present new species is very close to Hydrosmittia oxoniana (Edwards) , but differs from the latter by much slender stipes and the shape of virga with thorn-like spinules.

Figures

FIGURE 2 A – E. Hydrosmittia spinata sp. n. A. cibarial pump, tentorium and stipes. B. wing. C. virga, dorsal part. D. virga, ventral part. E. hypopygium, left dorsal aspect, right ventral aspect.