Paratanytarsus mirificus, Giłka, Wojciech & Dobosz, Roland, 2015

Giłka, Wojciech & Dobosz, Roland, 2015, A contribution to the systematics of Australasian Tanytarsini (Diptera: Chironomidae): first descriptions from New Caledonia, Zootaxa 3980 (1), pp. 127-135 : 130-132

Paratanytarsus mirificus sp. nov., Giłka

(Figures 2 and 4B)

Type material. Holotype, adult male: NEW CALEDONIA, Yaté, on river, 8 m a.s.l., 22° 9’17.39” S / 166°55’30.17” E, 3 March 2008, at light, leg. R. Dobosz.

Derivation of the name. The specific epithet (peculiar, quaint) refers to the extraordinary structure of the hypopygium and the antenna.

FIGURE 2. Paratanytarsus mirificus sp. nov., male. A —antenna (white arrows: borders between flagellomeres, fm11: ultimate 11th flagellomere), B —hypopygium, C —superior volsella, D —median volsella (C, D—magnified c. 2 times relative to B).

Diagnosis. Antenna short, with 11 flagellomeres, AR 0.24. Gonostylus shorter than gonocoxite, slender, with long subapical seta and pointed protuberance on apex. Superior volsella robust, roundish, with strong setae on median margin. Stem of median stout, slightly S-shaped, with bunch of subulate lamellae at apex and erect setiform lamellae on median margin.

Description. Adult male. Minute midge, wing length 885 Μm.

Colouration. Eyes black. Tentorium transparent. Head capsule, antenna, mouthparts, ground colour of thorax, legs and abdomen greenish yellow/pale brown. Wing transparent with yellowish undertone. Scutal stripes, scutellum, postnotum and sternum light brown.

Head. Eyes with well developed dorsomedian extensions gradually narrowing from 5 facets at base to 4, 3 and 2 facets medially. Antenna short, with 11 well discernible flagellomeres, ultimate flagellomere slightly swollen apically, short (97 Μm), AR 0.24; plume composed of long sparse setae (broken and missing on Fig. 2A). Frontal tubercles conical, minute, c. 5 Μm long. Lengths of palpomeres 2–5 (in Μm): 24, 52, 64, 115. Clypeus semicircular, with 15 setae.

Thorax chaetotaxy. Ac 10, Dc 6–7, Pa 2, Scts 4.

Wing. As shown in Fig. 4 B. FCu far distal of RM, VR Cu c. 1.65.

Legs. Fore leg tibia with straight spur, 12 Μm long. Combs of mid and hind leg tibiae slightly separated, small, composed of teeth up to 8 Μm long. Mid and hind leg tibiae each with two straight spurs of subequal length c. 15 Μm. Basitarsus of mid leg with 1 hook-shaped sensillum chaeticum. For lengths of leg segments and leg ratios see Table 3 .

Hypopygium (Fig. 2B–D). Gonostylus shorter than gonocoxite, c. 55 Μm long, straight and slender, distinctly narrowed in distal part, with long subapical seta and pointed protuberance on apex. Anal tergite with darkly pigmented separated bands of V-type, each band bearing 2 setae placed on well developed conical tubercles, lateral teeth absent. Anal point stout, broad at base, slightly narrowed subapically, apex blunt; broad flake-shaped crests arranged typically for Paratanytarsus and separated by subapical knob, 2 long lateral setae placed on each side of anal point (Fig. 2B). Superior volsella robust, roundish, slightly elongate and posteromedially directed, bearing 4 strong setae on median margin (including the strongest seta placed on distinct tubercle at base) and several (5) dorsal setae in posterolateral position (Fig. 2B, C). Digitus semitransparent, short, subtriangular, with tip pointed (Fig. 2B). Stem of median stout, swollen at base, broadest at mid length, narrowed distally, slightly S-shaped, bearing bunch of subulate lamellae at apex and erect setiform lamellae on median margin (Fig. 2D). Inferior volsella reaching half length of gonostylus, with apical part slightly swollen and posteromedially turned (Fig. 2B).

Remarks. According to traditional diagnoses for Paratanytarsus based on Holarctic species (e.g. Cranston et al. 1989), adult males of this genus have 13 antennal flagellomeres, separated mid and hind leg tibial combs, each with spur, V-shaped anal tergite bands, and the best diagnostic character found in majority of species is the shape of hypopygial crests - curved, flake-shaped, giving a rounded appearance. However, recent discoveries of several unusual species resulted in emendations to that definition (e.g. Giłka 2009, Bolton et al. 2010, Trivinho-Strixino 2010). The abbreviated antenna composed of 11 flagellomeres, the extremely low AR and the robust roundish superior volsella found in the adult male of Paratanytarsus mirificus are further unique characters indicating the great heteromorphism in this genus.

Figures

FIGURE 4. Wing of male: Cladotanytarsus (C.) stylifer sp. nov. (A), Paratanytarsus mirificus sp. nov. (B), Tanytarsus fuscithorax Skuse, 1889 (C).

Tables

TABLE 3. Leg segment lengths (μm) and leg ratios of male Paratanytarsus mirificus sp. nov.

	fe	ti	ta1	ta2	ta3	ta4	ta5	LR
p1	425	265	490	230	175	130	80	1.85
p2	445	300	185	80	65	50	45	0.62
p3	490	370	250	145	130	75	50	0.68