Penthetria montanaregis Skartveit, 2009: 13

Skartveit, John, 2021, A new fossil species of the genus Bibio, with an update on bibionid flies from Baltic and Rovno amber (Diptera, Bibionidae), Deutsche Entomologische Zeitschrift 68 (1), pp. 81-99 : 81

Penthetria montanaregis Skartveit, 2009: 13 Figs 2 , 15 , 16 , 17

Note.

The species was described based on a single, male specimen ( Skartveit 2009), however this specimen was to a large extent covered by white emulsion (Verlumung). The present specimen clarifies some aspects of the species’ morphology.

Holotype, male, MHNN 972. Additional material, male, JS-Baltic-001, in piece of amber 39 ×32× 3 mm.

Redescription of the species.

Male: Total length 6.3-7.9 mm (N = 2). Colour uniormly dark, probably brownish-black in life.

Head (Fig. 16 ): Length 0.75 mm, width 1.05 mm (N = 1). Only just holoptic, complex eyes in contact only 2-3 ommatidia, meeting at distance similar to diameter of ocellar tubercle anterior to tubercle. Complex eye nearly bare, with very short, fine and sparse intraocular hairs. Ocellar tubercle small but fairly prominent, with few strong, short, dark brown setae on posterior face. Rostrum not protruding. Palp not possible to see in this specimen. Antenna: flagellum slightly conical, 8-segmented, 0.58 mm long, 0.09 mm wide, segments subquadrate when seen laterally.

Thorax: Length 1.35-1.84 mm (N = 2), width 1.16 mm (N = 1, smaller specimen). Dorsal side covered by Verlumung, surface structure not possible to see. With irregularly biseriate, short and fine, dark dorsocentral setae, notum otherwise practically bare. Haltere brown.

Wing (Fig. 15 ): Length approximately 5.6 mm, width 2.0 mm, length/width = 2.8 (N = 1). The wing is somewhat crumbled, exact vein measurements difficult to find. Brown fumose, costal cell mostly darkened, but unpigmented basally of humeral crossvein. Pterostigma and veins dark brown, distinctive but not particularly strong. Costa with fine setulae, veins otherwise bare. Costa extends a little beyond apex of R4+5. Humeral crossvein rather strong, vertical. Subcosta distinctive, relatively strong, but merges with R at humeral crossvein, not visible basally. R2+3 fine, straight, oblique, about 0.4 × length of R4+5. R4+5 moderately curved. R-M vertical. M basally not connected to R nor to CuA. Fork of M rather narrow. M-CuA pigmented only in posterior half (nearest CuA1). CuA1 rather straight, CuA2 bent caudad in apical fourth. CuP not prominent. Vein lengths, all in mm: Basal R 2.25, Rs 0.86, R2-5 0.36, R2+3 0.68, R4+5 1.58, R-M 0.17, basal M 2.25, distal M 0.45, M1 2.06, M2 1.61, M-CuA 0.15, CuA 1.54, CuA1 2.44, CuA2 1.73.

Legs: Dark brown, densely clad with strong, short, dark setae. Femorae moderately clavate, all tibiae and tarsi slender. Tibial spurs dark, straight and sharp.

Abdomen: Length 4.1 mm, width 0.9 mm (N = 1), slightly conical. Tergites shiny, brownish-black, with fine and rather short, dark brownish pile.

Terminalia (Fig. 17 ): Width of hypopygium 0.71 mm (N = 1). Epandrium bilobate, lobes rounded with dense, rather long, dark brown setae. Gonocoxite with robust, dark brown setae, Gonostylus length 0.39 mm, rather long, straight, apically a little expanded, on posterior margin with about 8 strong, dark brown setae. (note: the apparent shape of the gonostylus is rather different from the holotype of Penthetria montanaregis , but this is probably due to preservation in different angles. The apparent shape of the gonostylus in male Bibionidae is extremely dependent on perspective). Ejaculatory apodeme rather wide.

Figures

Figure 2. Penthetria montanaregis, male. JS-Baltic- 001. Photo: Marius Veta.

Figure 15. Penthetria montanaregis, male, wing. Scale bar: 1 mm.

Figure 16. Penthetria montanaregis, male, head and thorax. Scale bar: 1 mm.

Figure 17. Penthetria montanaregis, male, terminalia. Scale bar: 0.1 mm.