Bibio celasensis Théobald, 1937

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 61-64

publication ID	https://doi.org/ 10.5281/zenodo.259087
publication LSID	lsid:zoobank.org:pub:4676EE59-569B-4197-B108-9B32FD88E68E
DOI	https://doi.org/10.5281/zenodo.6039668
persistent identifier	https://treatment.plazi.org/id/03A9879C-FFC2-F403-45D3-323A7EE53BA6
treatment provided by	Plazi
scientific name	Bibio celasensis Théobald, 1937
status

Treatment

Bibio celasensis Théobald, 1937 View in CoL

(Figs. 53 – 55, 172 – 177)

Bibio celasensis Théobald, 1937: 139 View in CoL – 140.

Bibio conformans Théobald, 1937: 142 View in CoL . Syn.n.

Bibio obtusa Theobald 1937:140 and Bibio tenuiapicalis Theobald, 1937: 140 View in CoL are also probably synonyms for this species, but we have not succeeded in finding the types of these species.

Material examined. Syntypes of Bibio celasensis —more than 100 specimens on a plate 12X 14 cm (MHNM). Most of them poorly preserved. Bibio conformans —specimen (female) depicted by Théobald (1937, Pl. XXI, Fig. 12) FSL 392012—A19.

Fig. 166. Female, wing. NMB F1376/1.

Fig. 167. Female, head and thorax. NMB F1377/5. Fig. 168. Female, fore leg. NMB F1376/1.

Fig. 169. Female, hind leg. NMB F1376/1.

Fig. 170. Female, terminalia, dorsal. NMB F454. Fig. 171. Male, terminalia. NMB F2183.

Fig. 173. Male, habitus. MNHN Monteils 1.

Fig. 174. Female, habitus. MNHN Monteils 101.

Fig. 175. Female, head and thorax. MNHN Monteils 17. Fig. 176. Male, terminalia, dorsal. MNHN Monteils 1. Fig. 177. Female, terminalia, lateral. MNHN Monteils 39.

Additional material: Males: MNHN Monteils 1 (counterpart Monteils 61), 54, 59, 79, 99 (counterpart Monteils 106), 114, Camoins 29. Females: MNHN Monteils 8, 15, 17, 19, 22, 23, 27, 28, 42, 48, 49, 52, 60, 62, 66, 83, 93, 101, 107, 110, 121, 127, 130, 132, 137, 141, 160, 167, Célas 1, 2 females of uncertain origin.

Localities. Célas, Camoins, Monteils

Diagnosis. A medium-sized (6 – 9 mm) Bibio . Antenna short and robust, flagellum 7-segmented. Legs with femorae black, stout and clavate. Protibial spur about one third as long as anterior spine. Wing hyaline with dark Rveins, posterior veins colourless, basal part of R s two to three times as long as R-M.

Redescription. Male (fig. 173): Total length 6.0 – 7.5 mm (N=7).

Head: Length 1.04–1.17 mm (N=5), width 1.17 mm (N=1). Antenna short and robust, flagellum probably 7- segmented.

Thorax: Length 2.1–2.5 mm (N=5). Dark brown, presumably black in life. Haltere pale.

Wing (fig. 172): Length 4.1–5.2 mm (N=3), width 1.9 mm (N=1). R-veins brown, posterior veins colourless. Costa extends slightly beyond R4+5. Basal R s approximately as long as R-M. Pterostigma rather small, brown, distinctive.

Legs: Hind femur clavate, hind tibia apically truncate, rather slim. Legs uniformly dark brown. Fore femur 1.3–1.7 mm long (N=4), 0.44–0.58 mm wide (N=4), fore tibia 1.4 mm long (N=1), hind femur 1.9–2.2 mm long (N=5), 0.42–0.55 mm wide (N=5), hind tibia 1.9–2.0 mm long (N=3), 0.35–0.38 mm wide (N=3), hind first tarsomere 0.67 mm long (N=1).

Abdomen: Length 3.6–5.4 mm (N=5). Relatively slender.

Teminalia (fig. 176): Hypopygium width 0.80–0.84 mm (N=2). Gonostylus rather short, curved and digitiform as usual for genus.

Female (fig. 174): Total length 7.5 – 11.0 mm (N=28).

Head (fig. 175) Length 1.04–1.38 mm (N=24), width 0.81–1.21 mm (N=4). Antenna rather short, flagellum 7- segmented, 0.41–0.58 mm long (N=5). Ocellar tubercle low, not prominent. Compound eye medium-sized.

Thorax: Length 2.1–2.9 mm (N=28). Dark brown to black, probably black in life. Haltere pale brown.

Legs: Femorae dark brown, probably black in life, tibiae and tarsi brown. Femorae stout and spindle-shaped, hind tibia rather slender, tarsi slender. Protibia stout, spur short, approximately 1/3 the length of spine. Fore femur 1.5–1.8 mm long (N=16), 0.54–0.86 mm wide (N=16), fore tibia 1.6–1.8 mm long (N=4), hind femur 1.9–2.7 mm long (N=24), 0.47–0.65 mm wide (N=25), hind tibia 1.9–2.6 mm long (N=24), 0.25–0.48 mm wide (N=22), hind first tarsomere 0.59–0.73 mm long (N=11). The great variability in leg width is probably due to variations in the angle in which the legs are preserved, this is very difficult to judge in flattened fossils.

Wing: Length 5.4–7.3 mm (N=15), width 1.9–2.8 mm (N=10), hyaline, R-veins brown, posterior veins pale brown to colourless. Pterostigma rather small, brown. Basal part of R s approximately as long as R-M.

Abdomen: Length 4.1–7.8 mm (N=26), cylindrical, rather stout, brown.

Terminalia (fig. 177): Relatively small and inconspicuous, cerci rounded.