Corneliola avia Giłka et Zakrzewska, 2013

Giłka, Wojciech, Zakrzewska, Marta, Dominiak, Patrycja & Urbanek, Aleksandra, 2013, Non-biting midges of the tribe Tanytarsini in Eocene amber from the Rovno region (Ukraine): a pioneer systematic study with notes on the phylogeny (Diptera: Chironomidae), Zootaxa 3736 (5), pp. 569-586 : 575-579

Corneliola avia Giłka et Zakrzewska , sp. nov.

Type material. Holotype. Adult male, complete specimen preserved in 10 x 8 x 2 mm piece of amber (SIZ K- 7240, Fig. 3 A). Paratypes. Adult male (tarsus of right fore leg missing) in 8 x 7 x 6 mm piece of amber (SIZ K- 25833, Fig. 3 B; syninclusions: Acari, 2 specimens); adult male (tarsus of right fore leg missing) and female (tarsi of all left legs and right mid leg missing), syninclusions preserved in 20 x 19 x 9 mm piece of amber (SIZ K-6973, Fig. 3 C; other syninclusions: Collembola, 3 specimens).

Derivatio nominis. From Latin, meaning ‘grandmother’.

Diagnosis. As for the genus.

Description. Adult male (n = 3). Total length 1.70–2.2 mm; wing length 850–1165 Μm.

Head ( Fig. 3 D, E). Eyes hairy, with microtrichia between ommatidial lenses distinctly longer than height of lens (visible in transmitted light); well developed dorsomedian extensions of eyes gradually narrowing from 5–6 facets at base to 2–3 facets medially, apex rounded, reaching frons; frontal lobes convex, distinctly divided by sagittal suture, without tubercles. Antennal flagellum composed of 9–10 discernible segments, flagellomeres 9–11 or 12 (apparently less than 13, according to distribution of setae) separated in part or completely fused, AR c. 1.3 when flagellum measured as 9-segmented; plume fully developed. Length of palpomeres 2–5 (Μm): 32, 68–88, 72– 88, 133–149. Clypeals present but impossible to count, their tubercles weak.

Thorax ( Fig. 3 D, E). Antepronotum relatively well developed, scutum not overreaching antepronotum. Tubercle on scutum absent. Setae strong, complete in one specimen examined. Ac 14; Dc 6 on each side; Pa 1; at least 5–6 strong scutellars.

Wing ( Fig. 4 A). Spatulate, with anal lobe not developed, broadest at 2/3 length, width: 283–362 Μm, length/ width ratio 3.00–3.22, apex widely rounded. RM parallel or slightly oblique relative to R. FCu placed distally of RM; VR Cu 1.35–1.38. Veins ending as follows (from base to tip): An, Sc, Cu1, R1, R2+3, M3+4, R4+5, M1+2; ends of R1, R2+3, R4+5 equidistant (VR C 1.0). Distal section of Cu1 sinuous. Wing membrane covered with dense macrotrichia except basal part.

Legs. Tibia of fore leg with 2–3 strong subapical bristles (length: 110–120 Μm), spur absent, at most vestigial dentiform process on apex. Tibial combs of mid leg small, teeth up to 10 Μm long, one comb with single slender c.

20 Μm long spur, second comb with slightly elongated spur-like tooth; combs of hind leg broadly separated, fanshaped, teeth c. 12 Μm long, each comb with slender spur c. twice the length of the longest tooth. Sensilla chaetica on ta1 of p2 not observed. Pulvilli absent. For length of leg segments and leg ratios see Table 3 .

Hypopygium ( Fig. 4 B–H). Gonostylus cylindrical, straight or slightly curved, slender, 70–100 Μm long, much longer than gonocoxite, with strong spine-like apical bristle ( Fig. 4 D, E). Anal tergite semicircular, bearing several strong median setae. Anal point short, triangular or somewhat lanceolate, apex blunt, spinulae and crests absent ( Fig. 4 D, F), bearing 6–8 posterolateral setae on each side. Superior volsella slender, conical, slightly swollen in proximal part, with distinct digitiform extension, apex blunt; 3 setae placed on anteromedian margin ( Fig. 4 D, G). Digitus absent. Stem of median volsella c. 20–25 Μm long, straight, posteriorly directed, bearing setiform and slender spindle-shaped lamellae ( Fig. 4 H). Inferior volsella reaching half length of gonostylus at most, narrowed in mid length and slightly bent medially, swollen, head-like apical part, armed with several stout curved setae ( Fig. 4 D).

Adult female (n = 1). Total length c. 1.2 mm; wing length 630 Μm.

Head ( Fig. 5 A). Eyes hairy, as in male. Frontal tubercles absent. Antenna with 6 clearly separated flagellomeres: 35, 34, 50, 53, 39, 67 Μm long. Palps similar to those found in male; length of palpomeres 3–5 (Μm): 84, 82, 145. Clypeus with 12 setae.

Thorax ( Fig. 5 A, B). Antepronotum relatively well developed, but slightly weaker than in male. Tubercle on scutum absent. Setae strong, but poorly countable in the specimen examined. Ac at least 6, Dc at least 6 on one side, Pa and Scts unobservable.

Wing ( Fig. 5 B). As in male, with usual sexual differences. Width: 270 Μm, length/width ratio: 2.33.

Legs. Tibial spurs and combs as in male. For length of leg segments and leg ratios see Table 4 .

Genitalia. Cercus 24 Μm long, 38 Μm high (in lateral view). Other diagnostic structures of genitalia unobservable.

Figures

FIGURE 3. Corneliola avia sp. nov. A – C— type series: A— holotype, male; B— paratype, male; C— paratypes, male and female (syninclusions); D— male, habitus (holotype); E— thorax and head of male with 11 / 12 - segmented antennal flagellum.

FIGURE 4. Corneliola avia sp. nov., male. A— wing; B – H— hypopygium: B, D— dorsal aspect, C— ventral aspect; E— apical bristle of gonostylus; F— anal point (variation); G— superior volsella; H— median volsella (E, G, H— magnified twice relative to hypopygium drawn).

FIGURE 5. Corneliola avia sp. nov., female. A— head with 6 - segmented antennal flagellum, B— habitus.

Tables

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

fe	ti	ta1	ta2	ta3	ta4	ta5	LR
P1 500–560	260–340	550–720	300–400	240–310	180–240	80–95	1.76–2.31
P2 475–590	380–490	270–365	125–165	105–125	70–90	50–60	0.70–0.87
P3 515–590	455–580	365–455	185–255	165–215	105–135	50–65	0.74–0.81