Archistempellina falcifera 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 : 573

publication ID	https://doi.org/ 10.11646/zootaxa.3736.5.8
publication LSID	lsid:zoobank.org:pub:D961FDF8-B2FB-4B63-A01A-45A1978FC6D4
DOI	https://doi.org/10.5281/zenodo.6161842
persistent identifier	https://treatment.plazi.org/id/03E687CE-EA12-FFF1-FF0B-FED649E8F832
treatment provided by	Plazi
scientific name	Archistempellina falcifera Giłka et Zakrzewska
status	sp. nov.

Treatment

Archistempellina falcifera Giłka et Zakrzewska View in CoL , sp. nov.

Type material. Holotype. Adult male (tarsus of left mid leg and both hind legs missing) in 13 x 7 x 7 mm piece of amber (SIZ K-8884, Fig. 2 View FIGURE 2 A; syninclusion: undeterminable chironomid female).

Derivatio nominis. From Latin, meaning ‘bearing sickles’, in reference to the bifid falciform hypopygial median volsellae.

Diagnosis. Tibia of fore leg with strong subapical bristles, spur absent; femur of mid leg longer than femur of hind leg. Anal point with swollen roundish tip, reaching bases of median and inferior volsellae. Superior volsella very small, cylindrical. Stem of median volsella and its falciform lamellae of the same length.

Description. Adult male (n = 1). Total length 3.5 mm; wing length c. 1610 Μm.

Head ( Fig. 2 View FIGURE 2 B, C). Eyes bare, with well developed dorsomedian extensions. Frontal tubercles not observed. Antenna with 13 well discernible flagellomeres, AR 1.26, plume fully developed ( Fig. 2 View FIGURE 2 C). Length of palpomeres 3–5 (Μm): 156, 163, 277. Long clypeals present but uncountable in lateral position.

Thorax ( Fig. 2 View FIGURE 2 B). Antepronotum relatively well developed, scutum not overreaching antepronotum. Tubercle on scutum absent. Ac at least 12, Dc at least 14 on each side, Pa 3 on each side, Scts at least 7.

Wing ( Fig. 2 View FIGURE 2 D). Slender, with anal lobe weak, broadest at 2/3 length, width: 406 Μm, length/width ratio 3.97. RM slightly oblique relative to R. Ends of Sc and R2+3 fading, not visible; R1 arcuate. FCu placed distally of RM; VR Cu 1.25. Veins ending as follows (in order from base to tip): An, Cu1, R1, M3+4, R4+5, M1+2. An fading in distal part, reaching FCu at most. Wing macrotrichia unobservable.

Legs. Tibia of fore leg with 4 strong subapical bristles, spur absent. Single tibial comb of mid leg fan-shaped, teeth up to 20 Μm long, with single slender c. 30–40 Μm long spur; combs of hind leg broadly separated, fanshaped, one comb broad, teeth up to 12–16 Μm long, without spur, second comb narrow, teeth up to 20 Μm long, bearing 50–55 Μm long spur. Sensilla chaetica on ta1 of p2 not observed. Pulvilli absent. For length of leg segments and leg ratios see Table 2 View TABLE 2 .

Hypopygium ( Fig. 2 View FIGURE 2 E–J). Gonostylus cylindrical, straight, tapering to conical apex, c. 135 Μm long, much longer than gonocoxite, with apical seta. Anal tergite subtriangular. Anal point slender, styliform, with swollen roundish tip, without spinulae and crests, bearing at least 4 posterolateral setae on each side; anal point reaching bases of median and inferior volsellae; upturned in lateral view with tip bent down ( Fig. 2 View FIGURE 2 E–H). Superior volsella very small, cylindrical, slightly swollen in distal part, bearing at least 2 setae at rounded apex ( Fig. 2 View FIGURE 2 I). Digitus absent. Stem of median volsella about the size and shape of superior volsella, c. 20 Μm long, slightly curved, medially directed, bearing 2 slender falciform lamellae; stem and lamellae of the same length ( Fig. 2 View FIGURE 2 J). Inferior volsella reaching 1/3 length of gonostylus at most, club-shaped, with distinctly enlarged head-like apical half, armed with several stout and strongly curved setae.

Remarks. Apart from the characters listed in the diagnoses, Archistempellina falcifera and A. bifurca differ from each other in their general dimensions and colouration; however, in amber inclusions, the latter feature cannot be used with any certainty.