Clunio jonesi, Saether, Ole A. & Andersen, Trond, 2011

Saether, Ole A. & Andersen, Trond, 2011, Chironomidae from Gough, Nightingale and Tristan da Cunha islands, Zootaxa 2915, pp. 1-19 : 13-15

Clunio jonesi sp. n.

( Figs 23–27 )

Clunio africanus Freeman (1962: 78) , not Hesse, 1937: 165.

Type material. Holotype male, GOUGH ISLAND: Site SB1 at Seal Beach, 40o20'667"S, 0 9o 52'199"W, supralittoral, 5 m a.s.l., 2000, Malaise, C. Hänel & A.G. Jones ( ZMBN). Paratypes: 5 males, as holotype ( BMNH, TCD, ZMBN).

Etymology. Named in honor of the collector Dr. A. G. Jones.

Diagnostic characters. The species resembles C. africanus Hesse, 1937 and C. gerlachi Saether, 2004 in having hairy eyes, strongly curved tibial spur and in the strongly incised third tarsomere on the hind leg as well as in the shape of the aedeagus. It differs by having ultimate flagellomere as long as the 4 preceding segments (as long as 3 preceding segments in C. africanus , as 6–7 preceding in C. gerlachi ), scutellum with 18–26 setae (as opposed to 12–14 in C. gerlachi ), all legs with only one tibial spur and gonostylus with only 1–2 apical spines (as opposed to 5–10 in C. gerlachi and C. africanus ). Cu1 is strongly and abruptly curved and sometimes recurved at apex, differing from the other two species with more gently curved Cu1.

Description. Male (n = 6, except when otherwise stated). Total length 2.02–2.84, 2.49 mm. Wing length 1.52– 2.15, 1.86 mm. Total length / wing length 1.22–1.41, 1.34. Wing length / length of profemur 3.57–4.01, 3.75.

Coloration. Pale brown with hypopygium darker.

Head. Eyes hairy. Scapus 64–75 μm (3) long, 60–75 μm (3) wide. Pedicel 64–83, 73 μm long; 53–64, 60 μm wide. Antenna ( Fig. 23 ) with 9 flagellomeres, ultimate flagellomere as long as 4 preceding flagellomeres, basal flagellomere 0.80–1.09, 0.97 times as long as ultimate. AR 0.35–0.45, 0.38. Lengths (in μm) of flagellomeres: 124–188, 150; 34–49, 43; 30–45, 37; 30–45, 37; 32–41, 38; 32–41, 38; 34–45, 40; 30–41, 37; 128–173, 156. No temporal setae. Clypeus without setae. Tentorium 68 μm (2) long, 11–15 μm (2) wide. Basal palpomere 19–26, 22 μm long; second palpomere 41–56, 50 μm long.

Thorax. Dorsocentrals 4–6, 5; acrostichals 3–4, 4, far anterior; prealars 3–7, 5. Scutellum with 18–26, 22 setae in multiserial transverse rows.

Wing ( Fig. 24 ). VR 1.23–1.39, 1.31. R with 1–5, 3 setae; R1 with 1–4, 2; R4+5 with 3–6, 5 setae; other veins bare. Cu1 strongly and abruptly curved and sometimes recurved at apex.

Legs. Spur of fore tibia 26–45, 33 μm long; of mid tibia 26–45, 36 μm long; of hind tibia 34–56, 43 μm long; all spurs strongly curved at apex. Width at apex of fore tibia 49–71, 61 μm; of mid tibia 47–71, 57 μm; of hind tibia 53–81, 63 μm. Lengths and proportions of legs as in Table 5.

Hypopygium ( Figs 25–27 ). Tergite IX with 2–17, 10 strong setae and 2–8, 5 very weak lateral setae. Gonocoxite 416–525, 458 μm long; with about 8–10, 9 setae on inner apical margin. Gonostylus 255–326, 286 μm long; with 1–2, 2 apical spines; 4–11, 8 μm long; inner fold also with 1 weak, but broad spine, 4–11, 7 μm long at apex. HR 1.57–1.63, 1.60; HV 0.79–0.92, 0.87.

Remarks. The genus Clunio Haliday, 1855 is in need of revision. However, C. jonesi differs from C. pacificus Edwards, 1926 by having hairy eyes and strongly curved tibial spur; from C. africanus Hesse, 1937 and C. gerlachi Saether (Saether 2004: 294) by having ultimate flagellomere as long as the 4 preceding segments, stronger curved Cu1 and only 1–2 apical spines on the gonostylus; from C. tuthilli Tokunaga (Tokunaga 1964: 537) by the few apical spines on the gonostylus and an entirely different aedeagus; from C. marinus Haliday by the strongly incised third tarsomere on the hind leg, the strongly curved tibial spurs and more numerous setae on the scutellum. However, according to Edwards (1926 fig. 2a) there are 9 flagellomeres in C. marinus while Tokunaga (1964: 537) mentions 10 flagellomeres indicating that they have different species. The hypopygium is similar to that of C. marinus as for instance illustrated by Strenzke (1960 figs 11–14).

Ecology and distribution. It is remarkable that a Clunio could be collected in a Malaise trap as the adults ‘skate’ on the water surface. The species is known from Gough Island.

fe ti ta1 ta2

p1 406–595, 496 595–898, 747 142–189, 167 47–66, 53

p2 510–718, 603 473–699, 581 95–113, 106 38–47, 43

p3 558–794, 669 539–775, 660 104–142, 126 38–57, 50

ta3 ta4 ta5 LR

p1 38–57, 45 38–47, 40 47–76, 57 0.21–0.24, 0.23

p2 33–38, 37 28–38, 31 43–66, 53 0.16–0.20, 0.18

p3 57–95, 79 28–47, 38 47–85, 65 0.18–0.21, 0.19

BV SV BR

p1 6.42–8.28, 7.34 6.94–8.06, 7.43 0.6–1.0, 0.9

p2 7.13–9.82, 8.18 10.40–12.50, 11.28 0.8–1.1, 1.0

p3 5.69–7.53, 6.41 9.71–11.07, 10.46 1.1–1.7, 1.3

Figures

FIGURE 23 – 27. Clunio jonesi sp. n., male. 23 — antenna; 24 — wing; 25 — hypopygium, dorsal view; 26 — hypopygium, ventral view; 27 — apodemes, dorsal view to the left, ventral view to the right.