Nymphomyia alissae, Wagner & Müller, 2020

Wagner, Rüdiger & Müller, Patrick, 2020, The oldest of the rare: A new species of the family Nymphomyiidae (Diptera) from Burmese amber, Zootaxa 4763 (2), pp. 287-293 : 288-291

Nymphomyia alissae sp. nov.

( Figs 1–12 )

Etymology. The species is dedicated to the junior author’s wife Alissa Müller.

Description (BUB 3295 - holotype male, allotype female)

Male. Body length 1.10 mm; head about 0.10 mm long, rostrum ( Figs 3 , 7, 8, 10 ) as long as width of eye bridge (in lateral view), distally curved ventrad with several setae dorsally. Antennae 3-segmented; scape slightly longer than wide, pedicel linked to scape subapically and obliquely; flagellum elongate ring-shaped sculptured, distally broader with (probably) 1 apical sensillum. Compound eyes large, dorsally separated, ventrally contiguous over a distance of 4 facet rows. Laterally behind compound eyes a pair of large lateral ocelli (bullae).

Thorax 0.30 mm long, wings missing; mesothorax dorsally prolonged forward forcing the small prothorax to a more ventral position; metathorax small with a pair of halters, twice as long as the height of the metathorax, api- cally with an elongate bean shaped knob. Legs are long and slender. Coxae strongly increasing in diameter apically, trochanter tubular, shorter than coxa; femur in the basal 40% paler and thinner than distally; tibia as well tubular, approximately as long as femur, in the basally paler part with ring-shaped folds, there with 2 setae; tarsus segment 1 as long as segments 2+3+4, segment 5 as long as 3+4; claws well-developed, empodium long setiform, reaching almost the tip of the claw.

Abdomen 0.81 mm long (terminalia 0.16 mm); segments 1, 5, 6 and 7 elongate, 2–4 shorter; tergites of segments 2–4 laterally with short medio-dorsal indentation, lateral edge with median cone-shaped prologations ( Fig. 11 ). Terminalia almost as long as segments 7 or 8; in lateral view gonocoxite elongate rhomboid, slightly sinuous, basally in the midst coadunate, 3x longer than the apical height, lower edge with a row of short bristles. Gonostylus arising from the dorsal angle of the gonocoxite, basally globular, abruptly thinner and then strongly hook-like bent ventrad.

Additional information. Male BUB 3296: body length 1.20–1.30 mm, wing length 1.00 mm; legs with coxae and femura entirely brown, femura and tibiae basally pale, apically brownish; tarsus segments with an apical brown ring, t 5 entirely brown, claws dark. Abdomen with segment 1 short, as long as high; segment 2 slightly longer than 1, tergite 2 broader; tergites 3–5 broad with lateral conical ends; segments 5 and 6 as long as the preceding, tergites without conical ends; segments 7 and 8 about 2x longer than high, sclerotization probably less; tergites 3–7 with a cross row of 6–7 tubercles. Terminalia with gonocoxites approximately 3x longer than the apical width.

Male BUB 3540: body length 1.30 mm; eyes dorsally with 3 facet rows, broadly separate; rostrum well sclerotized, tip bent ventral, hooked; apical part of pedicellus oblique so that the flagellum is inserted subapically on the inner surface, basal part of flagellum as long as distal part, apically with 1 sensillum.Abdomen similar to male BUB 3296, tergites 3–5 pulled downwards laterally with median conical ends; remaining segments as in male BUB 3296; a cross row with 6–7 tubercles on tergites 2–6. Terminalia with gonocoxites coadunate in the middle, approximately 4x longer than the apical height; gonostyli linked dorsally to gonocoxites; between the gonocoxites an elongate finely sclerotized structure, basally slightly swollen, with a subapical constriction (aedeagus?).

Female. Body length 1.19 mm; head length 0.11 mm; rostrum similar to male; antenna as in male. Compound eyes are contiguous on ventral side of the head over the width of 4 ocelli. Head behind eyes as long as the eye width; with a pair of large lateral bullae ( Figs 1, 4, 6 ).

Thorax 0.32 mm long; thorax sections arranged as in the male, legs similar to male; tarsi with paired claws, empodium distinct. Wings ( Fig. 9 ) translucent 0.70 mm long, elongate, scimitar shaped, curved forward in the apical fifth, with only a single vein fading just before the apical curve of the wing; a fringe of long setae along the wing margin.

Abdomen 0.56 mm long; segment 1 pipe shaped and longer than segments 2–6; segment 7 small, less sclerotized. Tergites probably without cross line of tubercles and lateral conical ends. Terminalia are complex, remarkably large and well sclerotized, triangular in lateral view. Dorsally with a pair of large elongate triangular setose cerci, the lower edge more than 2x longer than the lower edge of the terminalia, along the ventral and the apico-dorsal edges with series of longer setae; the cerci descend from the apico-lateral corner of a large cross sclerite. The ventral part is brownish, triangular, ventrally with 2 lateral sharp corners, along the apical edge with a median outgrowth.

Additional information: Female BUB 3299: eyes dorsally separated by a width of 4–5 ocellus diameters. It is not evident whether there are 1 or 2 dorsal sclerites from which the cerci descend.

Female BUB 3298: At the basis between cerci lies a translucent flexible structure.

Figures

FIGURES 1–6. Nymphomyia alissae new species. 1—BUB 3295 holotype (male) and female allotype; 2—BUB 3296 paratype male (arrows indicate cone-shaped prolongations); 3—BUB 3296 paratype male, head and thorax; 4—BUB 3297 paratype female (arrow indicates cerci); 5—BUB 3296 paratype male, abdomen (bar—200µm); 6—holotype (male) and female allotype, abdomen and terminalia.

FIGURES 7–12. Nymphomyia alissae new species. 7—BUB 3297 female, head and thorax; 8—BUB 3296 male, head and thorax; 9—BUB 3298 female, head and fore part of thorax; 10—BUB 3298 female, wing; 11—BUB 3295 holotype (male) and female allotype, apical parts of abdomina with lateral prolongations (full line arrows) and dorsal dents (broken arrows); 12—BUB 3295 holotype (male) and female allotype, tips of abdomen with terminalia (c—cercus).