Pagastia (P.) subletteorum Makarchenko, 2019

Makarchenko, Eugenyi A., 2019, Review of the genus Pagastia Oliver (Diptera: Chironomidae: Diamesinae) from North America, with description of P. (P.) subletteorum sp. nov., Zootaxa 4664 (1), pp. 115-128 : 117

Pagastia (P.) subletteorum Makarchenko , sp. nov.

( Figs. 1–6 , 19–20 )

urn:lsid:zoobank.org:act:9E86BA90-9FA7-449B-90A5-D1F00F41A616

Material. Holotype: adult male (slide number 3), Canada: British Columbia Province, St. Mary Lake, roughly 10 miles west of Kimberley ( North of Cranbrook ), 25.IX. [no year given], leg. C.B.D. Garrett. Paratypes: 7 adult males, same data as holotype .

Derivatio nominis. The species is named in honour and memory of the American chironomid taxonomists Mary F. and James E. Sublette.

Adult male (n = 2).

Total length 4.24 mm. Total length/wing length 1.25–1.31.

Coloration (specimens in Canada balsam). Head, thorax, legs, and abdomen brown to dark brown; antennae light brown; wings greyish.

Head. Eyes slightly pubescent and strongly extended dorsomedially. Temporal setae 29–34, including 4 coronals, 7 preoculars, 14–18 verticals, and 4–5 postorbitals. Clypeus with 17–20 setae. Antenna with 13 flagellomeres and slightly reduced plume, these setae 80–300 μm long; pedicel with 4–5 setae 32–40 μm long; terminal flagellomere with 1–2 subapical setae 54–60 μm long. AR 1.0–1.2. Palpomeres lengths (in μm): 40–48; 76–92; 160–164; 160– 176; 260–284. Palpomere 3 in distal part with sensilla capitata (diameter 12–14 μm). Palpomeres 1–5 length/head width 0.82–1.19.

Thorax. Antepronotum with 7–8 dorsomedial and 11–12 ventrolateral setae. Acrostichals 19–20 (32–64 μm long), dorsocentrals 26–32 (in 1–2 rows), prealars 19–20, scutellars 35–36.

Wing. Length 3.24–3.40 mm; width 0.88–1.0 mm. Membrane with setae 32–48 μm long on wing apex. R and R 1 with ca 90–100 setae; R 4+5 with ca 60–80 setae; M 1+2 with 25–29 setae; M 3+4 with 29–38 setae; Cu 1 with 28–30 setae. Setae on R, R 1, R 4+5 36–44 μm long, on other veins 28–36 μm long. Costa extension 80–108 μm long. RM length/MCu length 2.83–3.2. Anal lobe developed, outline angular. Squama with 32–36 setae 72–96 μm long, in 2 rows. Alula with 5 setae 40–64 μm long. VR 0.82–0.90.

Legs. Spur of fore tibia 52–64 μm long; spurs of mid tibia 52–56 μm; of hind tibia 76–88 μm and 52 μm long. Hind tibial comb with 14 setae. Lengths and proportions of leg segments as in Table 1 .

Hypopygium ( Figs. 1–6 , 19–20 ). Tergite IX without anal point, with 17–21 setae on one side. Laterosternite IX with 20–21 setae. Transverse sternapodeme 200–220 μm long. Phallapodeme 116–128 μm long. Median aedeagal lobe absent; lateral aedeagal lobe 124–128 μm long, with wide basal half and narrow distal portion with a sharply triangular projection on the outer edge. Gonocoxite 236–248 μm long. Gonostylus 164–168 μm long, rugose, scarcely widened in basal part, without megaseta. HR 1.44–1.48.

Pupa and larva unknown.

Diagnosis. The male of this new species differs from all known species by the absence of an anal point on tergite IX and by the presence of some setae on the alula, M 1+2, M 3+4, and Cu 1 of the wing, as well as by the low antennal ratio of only 1.0–1.2. See also key below.

Figures

FIGURES 1–6. Pagastia (P.) subletteorum sp. nov., male. 1, hypopygium in dorsal view; 2, inner structures of hypopygium; 3– 4, gonostylus in various aspects; 5, part of tergite IX; 6, gonocoxite and gonostylus in dorsal view. Bl, basal lobe of gonocoxite; LAl, lateral aedeagal lobe; Pha, phallapodeme; TSa, transverse sternapodeme. Scale bars: 50 µm.

FIGURES 19–20. Pagastia (P.) subletteorum sp. nov., male. 19, hypopygium in dorsal view; 20, gonostylus.