Pagastia (Pagastia) donoliveri Makarchenko et Hansen 2020, sp. nov.
Creators: name: Makarchenko, Eugenyi A.
name: Hansen, Dean C.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Chironomidae
Pagastia
Pagastia donoliveri

description: Pagastia (P.) donoliveri Makarchenko et Hansen, sp. nov.
(Figs. 1–9)
urn:lsid:zoobank.org:act: 9E21409F-D361-41D5-B5A6-FF0857DC8C56
Material. Holotype: adult male, U.S.A.: Wyoming, Park County, Beartooth Pass region, Malaise trap over small stream feeding Frozen Lake, alt. 3127 m above sea level, N 44°57’42.12”, W 109°29’08.12”, 30–31.VIII.2017, leg. Dean C. Hansen. Paratype: 1 adult male, same data as holotype.
Derivatio nominis. The species is named in honour of the Canadian chironomid taxonomist Donald Raymond Oliver.
Adult male (n = 2).
Total length ca 5.4–5.6 mm.
Coloration (specimens in Euparal). Head, thorax, legs, and abdomen brown to dark brown; antennae light brown; wings greyish.
Head. Eyes bare and strongly extended dorsomedially (Fig.1). Temporal setae 33–52, including 4 coronals, 8– 14 preoculars, 14–22 verticals, and 7–11 postorbitals. Clypeus with 23–24 setae. Antenna with 13 flagellomeres and developed plume, these setae 328–590 μm long; pedicel with 3 setae 56–64 μm long; terminal flagellomere with 1 subapical setae 50–52 μm long; flagellomeres lengths (in μm): 72–76; 28; 24–28; 32; 36–40; 36–40; 40–44; 40–42; 42–44; 44; 44–52; 44–48; 592–636; AR 1.22–1.26. Palpomere lengths (in μm): 60–68; 96–100; 192–196; 168–208; 260. Palpomere 3 distally with sensilla capitata (diameter 12 μm). Palpomeres 1–5 length/head width 0.95–1.24.
Thorax. Antepronotum with 6–7 dorsal and 13–18 lateral setae. Acrostichals 19–26 (60–92 μm long), dorso- centrals 41–43 (in 1–2 rows in anterior 2/3 and in 3 rows in posterior 1/3), prealars 22–24, scutellars ca 55 (Figs. 2–3).
Wing. Length 4.28–4.36 mm; width 1.16 mm. Membrane with setae 20–24 μm long on wing apex. R and R 1 with 59–64 setae in 1–2 rows; R 4+5 with 34–35 setae. Setae on R, R 1, R 4+5 40–52 μm long. Costa extension 49–66 μm long. RM length/MCu length 2.5–3.3. Anal lobe developed, outline rounded. Squama with 40–46 setae 48–152 μm long, in 1–2 rows. VR 0.84–0.93.
Legs. Spur of fore tibia 88–92 μm long; spurs of mid tibia 68–72 μm and 72–76 μm; of hind tibia 112–116 μm and 72 μm long. Hind tibial comb with 10 setae. Lengths and proportions of leg segments as in Table 1.
Hypopygium (Figs. 4–9). Tergite IX with 20–25 setae on each side 64–120 μm long. Anal point almost parallelsided in dorsal view, 72–88 μm long, with narrow seta-like apical peg 28 μm long (Fig. 8). Laterosternite IX with 7– 11 setae. Transverse sternapodeme narrow, anterior margin nearly straight. Phallapodeme with lateral aedeagal lobe only (Fig. 5), these 172–196 μm long, elongate and tapering to thin rounded apex. Gonocoxite 320–328 μm long, with basal plate and lobe-like median field. Gonostylus 196–224 μm long, narrow and ribbed, with rounded basal lobe in outer side and with lobe-like “heel” apically; megaseta 16–20 μm long (Figs. 4, 6–7, 9). HR 1.46–1.63.
Pupa and larva unknown.
Diagnosis. The male of the new species is most closely related to the Japanese species P. (P.) hidakamontana Endo, but it may be clearly distinguished from later by the shape of the gonostylus and some other features, namely the gonostylus with a rounded basal lobe in its outer side and a lobe-like “heel” apically; anal point of tergite IX 72–88 μm long, with narrow seta-like apical peg 28 μm long (Figs. 4, 6, 7, 9); AR 1,22–1,26. Gonostylus of P. (P.) hidakamontana with small basal lobe in outer side, apically rounded, without “heel”; anal point 100–116 μm long and apical peg broad, 24–33 μm long (Endo 2004, Figs. 1–6); AR 1.56–1.75. See also key below.
description: Published as part of Makarchenko, Eugenyi A. & Hansen, Dean C., 2020, Pagastia (P.) donoliveri sp. nov. - a new Nearctic alpine stream chironomid species (Diptera: Chironomidae: Diamesinae) from the Beartooth Mountains, Wyoming U. S. A., pp. 171-176 in Zootaxa 4755 (1) on pages 171-175, DOI: 10.11646/zootaxa.4755.1.9, http://zenodo.org/record/3724319