Mycetobia silvia, Wojtoń & Kania & Krzemiński, 2019

Wojtoń, Maciej, Kania, Iwona & Krzemiński, Wiesław, 2019, Review of Mycetobia Meigen, 1818 (Diptera, Anisopodidae) in the Eocene ambers, Zootaxa 4544 (1), pp. 1-40 : 24-25

Mycetobia silvia sp. nov.

( Figs 19–23 )

urn:lsid:zoobank.org:act:73DF6194-7EC9-4028-8C2D-F1321A5A188C

Diagnosis. Flagellomeres cylindrical, becoming narrowed and more elongated to the apex of antenna, flagellomeres 1–3 as long as wide, 4–7 more than 1x to 1.5x as long as wide, 8–13 elongated 2x as long as wide or longer, the last one 3x as long as wide, tapered at apex, last palpomere elongated, 8x as long as wide, tapered at apex, longer than second one; Sc ending behind Rs bifurcation level; the distance between R 1 and R 2+3 apices approximately 5x as long as the distance between Sc and R 1 apices; R 1 apex beyond M 1+2 bifurcation level; R 2+3 2.5x as long as Rs; M 1 and M 2 narrowly bifurcated, M 1+2 distinctly shorter than M 1; the distance between M 1 and M 2 apices approximately one and half the distance between R 4+5 and M 1; the distance between M 1 and M 2 apices shorter than the distance between M 2 and M 3+4; R 2+3 and R 1 ending behind bifurcation of M 1+2 level, R 2+3 ending before half R 4+5 level; only prescutellar and apical scutellar setae thick and very elongated.

Etymology. The species name is dedicated to Sylwia Wojtoń, wife of Maciej Wojtoń.

Type material: Holotype: No. 1345(a) (sex unknown), Baltic amber, (coll. Scheele); Paratype: No. 1345(b) (female), Baltic amber, (coll. Scheele).

Remarks: two specimens are preserved in one piece of amber.

Description. Body ( Fig. 20A ) 4.85–4.90 mm long, dark brown with pale brown basal part of tibia and all segments of tarsus of all legs 4.84–5.03 mm long. Head width 0.77–0.87 mm, 0.69–0.84 mm high. Head and thorax combined 2.12 mm– 2.20 mm. Eyes occupying most of head in lateral view, in frontal view eyes separated by a distance about equal to diameter of ocellus; raised ocelli present and form equilateral triangle ( Fig. 21A ). Antenna 1.72 mm long ( Figs 19A ; 21 A–E) with 14 cylindrical flagellomeres, more or less elongated, scape and pedicel comparatively short and wide; all flagellomeres with comparatively elongated and thick setae, but setae much shorter than segments bearing them and rather sparse; additionally short setae on all flagellomeres, tapered at apex last flagellomere with a few not very elongated setae at apex, last segment of antenna longer than penultimate one; palpus maxillaris 4-segmented ( Figs 19B ; 21F, G ) 0.35–0.36 mm long, second palpomere 0.14 mm, third 0.08 mm, fourth 0.14 mm long. palpomere comparatively elongated, second palpomeres cylindrical, third palpomere widened, 2x as long as wide; third palpomere not very elongated; last one elongated and tapered at apex, longer than penultimate one; not numerous and short setae on all palpomeres.

Thorax ( Figs 20A, B ): prescutellar setae and apical scutellar setae very elongated; acrostichal setulae not very elongated; wing ( Figs 19D ; 20A ; 22 A–D): 4.00 mm– 4.20 mm long, 1.69 mm wide; Sc comparatively elongated, slightly arched; Rs very short, 0.34 mm long, vein R 2+3 short, 0.98 mm, twice as long as Rs; R 1 apex before midlength of R 4+5 level; R 4+5 arched; M 1 and M 2 approximately twice the length of M 1+2, A 1 well developed, connected with wind edge; Halter not very elongated with elongated stem and widened knob. Legs ( Figs 19C, E ; 23 A–F): coxa of fore, middle and hind coxa with elongated bristles; coxa, trochanter and femur of all legs dark brawn, fore tibia pale brown with darkened dorsal edge, middle and hind tibia darkened in distal part; tarsus of all legs with first tarsomere pale brown, distal part of second and third tarsomere darkened, fourth and last segment of tarsus dark brown; fore, middle and hind tibia with two unequal tibial spurs; tarsus comparatively elongated with last segment only slightly longer than penultimate one and not very elongated, rather slender claw and almost invisible empodium. Apical comb well visible on fore and hind legs. Tibial spurs of fore legs unequal 0.09 mm and 0.11mm long, middle equal 0.12 mm, hind 0.12 mm long. Fore leg 4.74–4.88 mm long, middle leg 4.96–5.34 mm long, hind legs 5.18–5.76 mm long. Fore coxa 0.84–0.89 mm long, trochanter 0.20–0.21 mm, femur 1.13–1.17 mm, tibia 1.04–1.10 mm, tarsus 1.50–1.51 mm long (0.69–0.77/0.22–0.26/0.21/0.14–0.15/0.17). Middle coxa 0.78–0.93 mm long, trochanter 0.18–0.22 mm long, femur 1.05–1.20 mm long, tibia 1.23–1.27 mm, tarsus 1.72 mm (0.86/0.27/0.28/0.18/0.18). The length of hind coxa 0.67–0.71 mm, trochanter 0.17 mm, femur 1.19–1.49 mm, tibia 1.27–1.51 mm, tarsus 1.88 mm (0.87/0.30/0.23/0.18/0.20).

Comparison. In contrast to other species of Mycetobia from Eocene, in M. silvia sp. nov. flagellomeres 8–13 are elongated, 2x as long as wide or longer. Moreover, in M. silvia sp. nov. R 1 apex is positioned beyond M 1+2 bifurcation level and Sc ending beyond Rs bifurcation level, while in other species R 1 apex is positioned before M 1+2 bifurcation level and Sc ending before or opposite Rs bifurcation level, like in M. szwedoi sp. nov.

Figures

FIGURE 19. Mycetobia silvia sp. nov. holotype, No. 1345(a) (sex unknown) (coll. Scheele). A. antenna; B. palpus maxillaris; C. tibial spurs of hind and middle legs; D. wing venation; E. diagram of relation between the length of legs: fore leg (F), middle leg (M), hind leg (H).

FIGURE 20. Mycetobia silvia sp. nov. holotype, No. 1345(a) (sex unknown) (coll. Scheele). A. habitus, latero-ventral view; B. head and thorax, lateral view.

FIGURE 21. Mycetobia silvia sp. nov. holotype, No. 1345(a) (sex unknown), (coll. Scheele). A. head, frontal view; B. antenna; C.–E. enlarged view of flagellomeres; F.–G. palpus maxillaris. Abbreviations: CE—compound eyes; f1–f14—flagellomeres; OC—ocelli; PED—pedicel; SC—scape; II–IV—palpomeres II–IV.

FIGURE 22. Mycetobia silvia sp. nov. holotype, No. 1345(a) (sex unknown), (coll. Scheele). A. wing venation; B. macrotrichia on wing venation; C. apex of wing with C apex visible; D. enlarged view of Sc apex and bifurcation of Rs.

FIGURE 23. Mycetobia silvia sp. nov. holotype, No. 1345(a) (sex unknown), (coll. Scheele). A. coxa of fore, middle and hind legs; B.–C. enlarged view of elongated bristles on middle coxa visible; D. tarsus of middle leg; E. tibial spurs of middle and hind legs; F. tarsus of hind leg. Abbreviations: CLW—claw; CX 1–CX 3—coxa of fore and hind legs; I–V—tarsomeres I–V; arrows without abbreviations point thick setae on tarsus.