Plecia morio ( Heer, 1849 )

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 55-57

Plecia morio ( Heer, 1849)

( Figs. 47 – 48, 154 – 159)

Bibio morio Heer, 1849: 222

Protomyia collossea Heyden & Heyden, 1865: 21 .Syn.n. Plecia collossea ( Heyden & Heyden, 1865) Statz, 1943: 14 Plecia lygaeoides ( Heer, 1849) sensu Théobald, 1937

Bibio morio Heer is not to be confused with Bibio morio ( Linnaeus, 1758) sensu Fabricius, 1787 (current name Hemipenthes morio (Linnaeus, 1758)) . This species was, however, described in the genus Musca and not in Bibio , so Bibio morio Heer is not a primary junior homonym.

Material examined. 1 female (part and counterpart) NHMUK In 39831 and 39860. Females FSL 391929, FSL 391941. MNHN Aix 411, 970, 1295, 1386, 1442. Syntype (female) of Protomyia collossea NHMUK In 58789.

Male (tentatively associated) MNHN Aix 388, 885, 1398.

Localities. Aix-en-Provence. Also from Rott, Germany.

The species was described from Radoboj, but we did not find the type specimen in SLJG nor in NHMW. However, the specimen recorded by Heer (1856: 33) from Aix-en-Provence is easily recognizable on being considerably larger than all other specimens recorded by Heer from Aix. The specimens fit Heer’s description well.

Diagnosis. A large (13 – 15 mm), dark Plecia species with dark wings which are darkened in the anterior half, at least in females. The species is easily separated from the other species from French Oligocene sediments by its size. The body proportions of the female are characteristic, with a very small head and large, cylindrical abdomen. Antennal flagellum is cylindrical and nine-segmented. Male: terminalia with long, slender and nearly straight gonostyli.

Redescription. Male: Total length 13.5–14.0 mm (N=3).

Head (figs. 156–157): Length 1.68 – 1.72 mm (N=3), width 1.72 – 1.84 mm (N=3). Brown. Antenna relatively long and slender, flagellum probably 9-segmented. Interocular pile not apparent.

Thorax: Length 3.8 – 4.0 mm (N=3), width 2.8 – 3.2 mm (N=3). Brown, probably black in life. Haltere pale.

Wing (fig. 154): Length 10.0 – 11.5 mm (N=3), width 3.5 – 4.0 mm (N=3), length/width = 2.77 – 2.90 (N=3). Pigmentation of membrane and veins not preserved in any of the specimens at hand. Humeral vein and subcosta prominent, pterostigma indistinctive. R2+3 evenly curved, apical part of R4+5 rather straight. Fork of M relatively short. Wing vein measurements in Table 3 .

Legs: Not preserved in the specimens at hand.

Abdomen: Length 8.5 – 9.2 mm (N=3), width 1.6 – 1.8 mm (N=3). Light brown, relatively long and slender. Pile not apparent in the specimens at hand.

Terminalia: Dark brown. Hypopygium width 1.5 – 1.6 mm (N=3). Epandrium posteriorly with wide, U-shaped indentation. Gonostylus 0.90 mm long (N=1), slender, nearly straight.

Female: Total length 14.0– 16.2 mm (N=7).

Head (figs. 158–159): Length 1.14 – 1.45 mm (N=4), width 1.22 – 1.64 mm (N=4). Brown, probably black in life, rather small. Antenna cylindrical, slender, flagellum 1.11 mm long (N=1), 9-segmented. Compound eye medium-sized, oval. Ocellar triangle low and indistinctive.

Thorax: Length 3.0 – 4.1 mm (N=7), width 2.4 – 3.3 mm (N=4). Dark brown, probably black in life. Pile not apparent in the specimens at hand.

Wing (fig. 155): Length 12.0 – 13.2 mm (N=8), width 4.2 – 4.7 mm (N=7), length/width = 2.66 – 3.09 (N=7). Brown, anterior half somewhat darker. Veins brown, strong and distinctive. Humeral vein and subcosta prominent. Pterostigma indistinctive. R2+3 evenly curved, rather short, apical part of R4+5 nearly straight. Costa extends a little beyond apex of R4+5. Wing vein measurements in Table 3 .

Fig. 154. Male, wing. MNHN Aix 1398.

Fig. 155. Female, wing. NHMUK In 39860.

Fig. 156. Male, head and thorax, dorsal. MNHN Aix 885. Fig. 157. Male, head and thorax, ventral. MNHN Aix 1398. Fig. 158. Female, head. NHMUK In 39831.

Fig. 159. Female, head and thorax. NHMUK In 39860.

Legs: Femorae and tibiae yellowish brown, tarsi dark brown, presumably black in life. Slender throughout, relatively short. Fore femur 3.1 mm (N=1), fore tibia 3.6 mm (N=1), hind tibia 4.6 mm (N=1). Abdomen: Length 9.9 – 11.8 mm (N=7), width 4.1 – 4.2 mm (N=2). Cylindrical, dark brown, probably black in life. Tergites and sternites with rather long, brown pile.

Terminalia: Cerci rather small, apically rounded.