Bibio giganteus Unger 1841
Creators: name: Skartveit, John
name: Krizmanić, Katarina
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Bibionidae
Bibio
Bibio giganteus

description: Bibio giganteus Unger, 1841
(Figs. 12–14, 32–33)
Bibio giganteus Unger, 1841: 427.
Syn. Bibio partschi Heer, 1849: 216. Syn. n.
Syn. Bibio maculatus Heer 1849: 219. Syn.n.
Penthetria Partschi (Heer) Pongracz, 1928: 172. Type material: Holotype (female) of Bibio giganteus SLJG (77605). This is the specimen depicted by Heer (1849, Pl. XVI, Fig. 10). Syntype of Bibio maculatus SLJG 77474. Holotype (female) of Bibio partschi NHMW (2007z013010001).
Additional material: Female (SLJG 235), wing (SLJG 35), wing and fragment of the rest of the specimen (SLJG 13). Heer mentioned one specimen and three wings. Female (NHMW D 1184), labeled as Bibio obsoletus. 3 females (CNHM 1836, 1840, 1842). Female, probably non-type, NHMW 1852.1.1007 (labeled as Bibio partschi).
Description
Female:Total length 12.5–17.7 mm (N=5).
Head: (Fig. 33) Length 1.4 mm (N=1). Black. Poorly preserved in specimens at hand. Complex eye rather small, rounded. Ocellar tubercle small. Antennal flagellum apparently short and stout, 0.41 mm long by 0.19 mm wide, possibly five- or six-segmented.
Thorax: Length 3.9–4.6 mm (N=4), width 3.2–3.6 mm (N=3). Dark reddish brown. Halter reddish brown.
Wing (Fig. 32): Length 10.0– 13.1 mm, width 3.7–4.4 mm (N=5). Brown fumose, costal cell conspicuously darkened, veins darkened, strong throughout. Pterostigma black, oval. Basal R s a little longer than R-M. Bm-Cu meets M 2 some distance beyond furcation of M. Veins M 1, M 2 and CuA 1 apically rather straight, CuA 2 a little curved. Vein measurements (all N=5): Subcosta 5.0– 6.8 mm, basal R 3.4–4.2 mm, distal R 1 2.6–3.3 mm, R s 1.0 – 1.6 mm, R 2–5 4.2–5.8 mm, R-M 0.4–0.6 mm., basal M 3.2–4.0 mm, distal M 0.8–1.4 mm, M 1 3.6–4.9 mm, M 2 3.2–3.9 mm, M-Cu 0.7–1.0 mm, CuA 2.0– 2.8 mm, CuA 1 5.0–6.0 mm, CuA 2 3.0–4.0 mm.
Legs: Dark brown, likely black in life. Protibia stout with a quite short spur. Length of fore tibia 2.8–2.9 mm (N=2), width 0.55–0.64 mm (N=2), length of hind tibia 4.2–4.7 mm (N=3).
Abdomen: Length 9.3–13.4 mm (N=5), width 3.3–4.3 mm (N=4). Tergites dark brown, pleura reddish brown. Cerci small and triangular.
Discussion: The nominal species Bibio giganteus, Bibio maculatus and Bibio partschi may appear distinctive since B. giganteus has conspicuously coloured wings, the others not. However, the morphometric traits of the wings are quite similar, and it seems most likely that the specimens classified as Bibio maculatus and Bibio partschi are Bibio giganteus specimens without preserved wing pigments. The similarity of B. giganteus and B. maculatus was noted already by Heer (1849: 219), who distinguished the two on the basis of B. giganteus having relatively longer abdomen (but the abdomen is notably swollen in the holotype of B. giganteus) and B. maculatus having marginally narrower wings. Heer (1849: 216) distinguished Bibio partschi principally by its wider abdomen, this trait is, however, almost certainly an artefact of post-mortem swelling due to partial decay of the specimen before it was covered by sediment. The senior author has also seen material of this species from the late Oligocene site of Rott, Germany (Skartveit & Wedmann in prep.)
description: Published as part of Skartveit, John & Krizmanić, Katarina, 2020, Revision of fossil Bibionidae (Insecta: Diptera) from the Miocene of Radoboj, Croatia, pp. 351-378 in Zootaxa 4759 (3) on pages 364-367, DOI: 10.11646/zootaxa.4759.3.3, http://zenodo.org/record/3741178