Chaetocladius longivirgatus, Stur, Elisabeth & Spies, Martin, 2011

Stur, Elisabeth & Spies, Martin, 2011, Description of Chaetocladius longivirgatus sp. n., with a review of C. suecicus (Kieffer) (Diptera: Chironomidae), Zootaxa 2762, pp. 37-48 : 44-45

publication ID	https://doi.org/ 10.5281/zenodo.204648
DOI	https://doi.org/10.5281/zenodo.6183100
persistent identifier	https://treatment.plazi.org/id/0F597542-426A-FFB4-85C8-9770FC07F8EA
treatment provided by	Plazi
scientific name	Chaetocladius longivirgatus
status	sp. nov.

Treatment

Chaetocladius longivirgatus View in CoL sp. n.

( Figs. 2 View FIGURES 1 – 2 , 4 View FIGURES 3 – 5 , 7 View FIGURES 6 – 7 , 10 View FIGURES 8 – 11 )

Chaetocladius suecicus (Kieffer) – Lehmann (1971), in part: distribution, phenology; Saether & Spies (2004, in part), distribution.

Etymology. The specific epithet refers to the relatively long virga in the adult male genitalia; it is to be treated as adjectival for the purposes of nomenclature.

Holotype: adult male (deposited at VM; genetic voucher AT208; Genbank accession number HM421322 View Materials ), NORWAY, Oppland, Dovre, Rondane Nationalpark, Vidjedalsbekken at Skranglehaugen, N 61.98186°, E 0 980454°, 1117 m a.s.l., Malaise trap M1, 23.–30.vi.2008, leg. T. Hoffstad.

Paratypes (listed alphabetically by country): GERMANY: 2 adult males (ZSM), Hessen, Rhön mountains E of Fulda, helocrene c. 40 m below peak of Wasserkuppe mountain ("Schluchtquelle" = locality "OC" in Lehmann 1971: 470; one of the spring sources of the Fulda river), 01.x.1953, leg. E. J. Fittkau (Fulda sample 615). — NOR- WAY (all at VM): 2 adult males (vouchers AT194, AT220; Genbank accession numbers HM421308 View Materials and HM421334 View Materials respectively), data as for holotype; 1 adult male (voucher AT451; Genbank accession number HM421543 View Materials ), as holotype, except N 61.98141°, E 0 9.80480 °, 1119 m, Malaise trap M2, 14.–21.vi.2008, leg. T. Ekrem; 1 adult male (voucher AT452; Genbank accession number HM421544 View Materials ), as holotype, except N 61.98219°, E 0 9.80451 °, 1115 m, Malaise trap M3, 30.vi.–07.vii.2008, leg. T. Hoffstad; 1 adult male (voucher AT453; Genbank accession number HM421545 View Materials ), as holotype, except N 61.98346°, E 0 9.80384 °, 1105 m, Malaise trap M5, 23.–30.vi.2008, leg. T. Hoffstad; 1 adult male (voucher AT408; Genbank accession number HM421503 View Materials ), as holotype, except øvre Vidjedalsbekken, N 61.97168° E 09.83606°, 1280 m, Malaise trap, 23.–30.vi.2008, leg. T. Hoffstad; 2 adult males, as holotype, except Dørålseter, N 61.99347°, E 09.80343°, 1032 m, Malaise trap, 02.vii.1986 & 23.viii.1986, leg. K. Aagaard; 1 adult male, Møre og Romsdal, Rauma kommune, Raudstøl, N 62.31456º, E 08.096175º, 13.–20.v.1992, leg. K. Aagaard & O. Hanssen; 1 adult male, data as in preceding entry, except Fiva, N 62.51038º, E 07.762057º, 02.–12.v.1995.

Additional material examined. GERMANY: 1 adult male and 1 pupal exuviae (see the Discussion section) on a single slide ( ZSM), Hessen, Rhön mountains E of Fulda, Fulda river upstream of Obernhausen, c. 1.5 km below its springs ("Erlenwald" = locality "1A" in Lehmann 1971: 470), 19.iii.1954, leg. E. J. Fittkau.

Diagnostic characters. The male imago can be separated from all other Chaetocladius species by the following combination of characters: Wing length 1.8–2.3 mm; AR 1.00–1.24; LR1 0.54–0.66; eyes weakly pubescent; anteriormost acrostichals close to antepronotum; humeral pit ovoid, dark with several patches in one larger spot; wing with few setae on squama and on wing veins R and R1+2, vein R4+5 bare (one specimen unilaterally with 1 seta); halters apically dark; median setae on tergite IX comparatively delicate; virga with spines about as long as anal point and with additional short spines near base ( Fig. 7 View FIGURES 6 – 7 ); anal point not hyaline at base, parallel-sided, apically rounded, reaching about as far posterior as inferior volsella; inferior volsella double, with a ventral patch bare of microtrichia. Gonostylus without projections or significant expansions, with one distal macroseta. HR 2.6–2.8.

Male imago (n = 6 unless otherwise stated). Wing length 2.03 (1.84–2.26) mm (n=12). Gonocoxite length/ wing length 93 (88–103) (n=11). Coloration brownish black. Halters dark brown at tips ( Fig. 2 View FIGURES 1 – 2 ).

Head. AR 1.13 (1.00–1.24) (n=11). Terminal flagellomere 490 (420–540) µm long. Temporal setae 10–14, including 2–5 inner verticals, 6–8 outer verticals and 1–3 postorbitals. Clypeus length 75–87 µm, with 4–7 setae. Palpomere lengths (in µm): 30–38, 50–58, 110–120, 90–100, 150–180.

Thorax. Antepronotum with 3–8 setae. Acrostichals 14–19, dorsocentrals 7–11 in one row, prealars 4–6. Scutellum with 4–8 setae in one transverse row.

Wing ( Fig. 3 View FIGURES 3 – 5 ). Costa barely extended. VR 1.01–1.05. Anal lobe less projecting than in C. suecicus ( Fig. 4 View FIGURES 3 – 5 ), not right-angled. Brachiolum with 1 seta; veins bare, except R with 8–14 and R1 with 0–1 setae. Squama with 4–8 setae.

Legs. Spur of front tibia 58–72 µm (n=5) long, spurs of middle tibia 23–25 µm and 26–28 µm (n=4) long, of hind tibia 50–60 µm and 17–25 µm long. Lengths and proportions of leg segments as in Table 4.

fe ti ta1 ta2 ta3 ta4 p1 730 (670–790) 870 (780–940)# 530 (460–600)# 290 (280–320) 215 (190–240) 135 (120–150) p2 765 (700–820) 780 (710–830) 340 (320–360) 215 (190–230) 160 (140–180) 105 (90–120) p3 860 (780–920) 945 (840–1040) 550 (480–610) 290 (250–320) 240 (200–270) 135 (110–150) continued.

ta5 LR BV SV BR (n=5–6) p1 90 (80–100) 0.61 (0.54–0.66)# 2.82 (2.69–2.91) 3.18 (3.08–3.44) 1.91 (1.70–2.10) p2 90 (80–100) 0.43 (0.41–0.45) 3.30 (3.14–3.44) 4.57 (4.36–4.78) 2.01 (1.77–2.4) p3 90 (80–100) 0.58 (0.56–0.60) 3.10 (2.97–3.28) 3.29 (3.18–3.43) 2.8 (2.30–3.50) Hypopygium ( Figs. 7 View FIGURES 6 – 7 , 10 View FIGURES 8 – 11 ). 14–24 median setae on tergite IX, laterosternite IX with 3–6 setae (n=5). Anal point 65 (62–68) µm long, parallel-sided and distally rounded. Length ratio anal point/wing> 0.25. Phallapodeme 104 (93–110) µm long; transverse sternapodeme 95 (88–100) µm long. Virga 80 (75–83) µm long, with up to 5 long, thin spines and 6–16 (n=10) shorter ones ( Fig. 7 View FIGURES 6 – 7 ). Gonocoxite 195 (188–202) µm long. Gonostylus 73 (68–77) µm long ( Figs. 7 View FIGURES 6 – 7 , 10 View FIGURES 8 – 11 ), megaseta 10–15 µm long. HR 2.69 (2.62–2.76). Inferior volsella ventrally square and dorsally tongue-shaped, ventrally without microtrichia in proximal half.

Pupa. See Discussion below.

Remarks. The long virga spines separate when the hypopygium is pressed under the cover slip. Two other Chaetocladius species with dark halters are currently recognized in Europe ( Edwards 1929, Goetghebuer 1942 in 1940–1950, Saether & Spies 2004). Of these, C. piger (Goetghebuer, 1913) differs from the new species by the triangular anal point and square inferior volsella; C. dissipatus ( Edwards, 1929) differs by the slender and delicate anal point and the much shorter virga.

Distribution. The new species is so far known only from a subboreal and an alpine mountain region in central and southern Germany (Rhön and Allgäu, respectively), and from the Rondane Mountains in Norway. Chaetocladius longivirgatus sp. n. has been found syntopically with C. suecicus .