Cladotanytarsus (Cladotanytarsus) stylifer, 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 : 128-130

Cladotanytarsus (Cladotanytarsus) stylifer sp. nov., Giłka

( Figures 1 and 4 A)

Type material. Holotype, adult male: NEW CALEDONIA, La Roque river (south of Poindimié), 30 m a.s.l., 20°56’23.06” S / 165°21’18.77” E, 6 April 2008, at light, leg. R. Dobosz.

Derivation of the name. The specific epithet (bearing stylus) refers to the strongly elongate styliform hypopygial anal point.

Diagnosis. Anal point styliform, slender and strongly elongate, evenly tapering towards narrowly rounded apex, bearing few spinulae at base and slender crests almost reaching the tip. Superior volsella pear-shaped, with field of microtrichia on proximal half. Digitus extending far beyond superior volsella, apically pointed. Stem of median volsella stout, with 3 strong furcate lamellae. Inferior volsella with distinct lateral knee-like extension at base.

Description. Adult male. Small midge, wing length 1065 Μm.

Colouration. Eyes black. Tentorium transparent. Head capsule, antennal flagellum, mouthparts, ground colour of thorax, legs and abdomen greenish yellow/pale brown. Wing transparent, with yellowish undertone. Antennal pedicel, scutal stripes, scutellum, postnotum and sternum brown to dark brown.

Head. Eyes reniform, broadly separated. Antenna with 13 flagellomeres, AR 0.62; plume fully developed. Frontal tubercles conical, minute, c. 3 Μm long. Lengths of palpomeres 2–5 (in Μm): 35, 77, 93, 155. Clypeus semicircular, with 14 setae.

Thorax chaetotaxy. Ac 10, Dc 7, Pa 1, Scts 4.

Wing. Shape, venation pattern and chaetotaxy typical for the genus, as shown in Fig. 4 A.

Legs. Fore leg tibia with slightly curved spur, c. 15 Μm long. Combs of mid and hind leg tibiae separated, composed of teeth up to 10 Μm long. Mid leg tibia with two spurs: one spur darkly pigmented, straight, c. 15 Μm long, second spur lightly pigmented, sinuous, c. 20 Μm long; hind leg tibia with single dark straight spur, c. 10 Μm long. Basitarsus of mid leg with 2 hook-shaped sensilla chaetica. For lengths of leg segments and leg ratios see Table 1 .

Hypopygium ( Fig. 1 ). Gonostylus shorter than gonocoxite, c. Μm 60 long, broadest at base, apically rounded. Anal tergite with V-type separated bands and several (5) median setae. Anal point styliform, slender and strongly elongate, evenly tapering towards narrowly rounded apex, bearing few (4) spinulae at base and slender crests almost reaching the tip of anal point ( Fig. 1 A, B). Superior volsella slender pear-shaped, broadest at base, narrowed in distal half and slightly swollen apically, bearing field of microtrichia on proximal half, 5 dorsal setae and 3 long setae placed on conical tubercles at base. Digitus straight or slightly curved, long, extending far beyond superior volsella, apically pointed ( Fig. 1 A). Stem of median volsella stout, c. 30 Μm long, slightly curved and posteromedially directed, bearing several setiform and 3 strong furcate lamellae ( Fig. 1 C, D). Inferior volsella broadest at base, tapering towards apex, with distinct lateral knee-like extension at base and slightly protruding dorsomedian ridge near apex, evenly curved posteromedially ( Fig. 1 D).

Remarks. At least three morphologically close relatives known from the Australasian and Indo-Pacific Regions should be compared with Cladotanytarsus stylifer to prevent misidentification, i.e.: C. bilinearis Glover, 1973 (South Australia, Queensland), C. conversus (Johannsen, 1932) (southern China, India, Indonesia, Thailand; also Europe) and C. isigacedeus ( Sasa et Suzuki, 2000) ( Japan, Ishigaki) ( Glover 1973, Langton & Garcia 2000, Sasa & Suzuki 2000); the latter species originally ascribed to Tanytarsus and here given in new combination. Adult males of all these species have the similar strongly elongate hypopygial anal point, but the length/shape of the gonostylus, frontal tubercles, the arrangement of spinulae, the shape of hypopygial volsellae and main metric characters allow to separate them, as shown in Table 2 . The males of other Cladotanytarsus species known from somewhat similar structure of hypopygium are also European C. cyrylae Giłka, 2001 , C. nigrovittatus (Goetghebuer, 1922) , and C. sagittifer Giłka, 2009 described from the Arabian Peninsula; however, except the anal point length or its general shape they differ distinctly from species compared above and can be easily determined (cf. Giłka 2009, 2011).

Figures

FIGURE 1. Cladotanytarsus (C.) stylifer sp. nov., male. A — hypopygium, B — anal point, C — median volsella, D — inferior volsella and stem of median volsella (B – D—magnified c. 2 times relative to A).

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

Tables

TABLE 1. Leg segment lengths (μm) and leg ratios of male Cladotanytarsus (C.) stylifer sp. nov.

	fe	ti	ta1	Ta2	ta3	ta4	ta5	LR
p1	525	255	675	330	250	185	-	2.65
p2	530	435	250	130	90	65	60	0.57
p3	535	535	365	215	185	120	80	0.68