Plecia livida ( Heer, 1856 )

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 48-51

Plecia livida ( Heer, 1856)

( Figs. 36 – 37, 39, 41, 132 – 143)

Protomyia livida Heer, 1856: 35

Protomyia brevipennis Heer, 1856: 35 Syn. n. Plecia livida ( Heer, 1856) Théobald 1937: 339 . Plecia brevithoracis Théobald, 1937: 409 Syn. n. Plecia cerestensis Théobald, 1937: 409 Syn. n. Plecia constricta Théobald, 1937: 342 Syn. n. Plecia flichei Théobald, 1937: 406 Syn. n.

Plecia fusciventris Théobald, 1937: 407 Syn. n. Plecia goreti Théobald, 1937: 409 Syn. n.

Plecia maculitarsis Théobald, 1937: 411 Syn. n. Plecia maculiventris Théobald, 1937: 411 Syn. n.

Material. Lectotype of Protomyia livida (female, herein designated), NHMUK In 39854. This is the specimen illustrated by Curtis (1829), Heer described the specimen with reference to this illustration. Paralectotype (female, herein designated) from Aix-en-Provence (ETHZ, Aix 120). The ETHZ specimen is labelled livida in Heer’s handwriting (partly obliterated).

Holotype (female) of Plecia goreti MNHN B 24516. Paratype (female) of Plecia guineri MNHN B 24415. Holotype (male) of Plecia maculiventris MNHN B 24523. Holotype (male) of Plecia brevithoracis EEFN (Coll. Fliche) F 298. Holotype (female) of Plecia fusciventris EEFN (Coll. Fliche) F 285. Holotype (female) of Plecia flichei EEFN (Coll. Fliche) F 310. Paratype (female) of Plecia flichei EEFN (Coll. Fliche) F 178. “Type” (male, exact status unclear) of Protomyia brevipennis MNHN B 24413. Syntype (male) of Plecia brevipennis NHM In 39830.

Localities. Céreste, Aix-en-Provence, Bois d’Asson, Barbeiras, Chadrat, Vitrolles.

Of the approximately 2570 numbered specimens from Céreste in RGL, 80 % probably belong to this species, though most are too poorly preserved for a certain species identification.

Diagnosis. A medium-sized Plecia , body length 5.5 – 10 mm (much of the variation due to post-mortem swelling), wing length 5 – 8.5 mm. Head with rostrum not at all produced. Flagellum short and 9-segmented in female, slender and 8-segmented in male. Femorae pale with dark tips, more distal leg segments usually dark. Wings light brownish in most specimens (other colours most likely due to post-mortem chemical changes), veins brown, distinctive throughout the wing. Abdomen yellowish-brown.

Redescription. Male: Total length 5.5 – 10.5 mm (N=100).

Head (fig. 134): Length 0.92 – 1.25 mm (N=22), width 1.00 – 1.45 mm (N=22). Brown. Compound eye seemingly naked. Antenna cylindrical, flagellum 8-segmented. Flagellum length 0.6 – 0.7 mm (N=2).

Thorax: Length 1.6 – 2.5 mm (N=55), width 1.3 – 1.6 mm (N=4). Brown. Haltere brown.

Wing (fig. 132): Length 5.0 – 6.8 mm (N=29), width 1.8 – 2.6 mm (N=29), length/width = 2.27 – 2.95 (N=29). Light brownish. Triangular with R2+3 short and curved. Veins distinctive and brown throughout wing. Pterostigma light brown, indistinctive. Wing vein measurements in Table 2.

Legs: Light brown. Fore tibia length 1.9 – 2.7 mm (N=19), fore first tarsomere 0.9 – 1.3 mm (N=10), hind tibia 2.8 – 2.9 mm (N=2).

Abdomen: Yellowish-brown, slender.

Fig. 133. Female, wing. RGL Céreste 476.

Fig. 134. Male, head and thorax, dorsal. RGL Céreste 1010. Fig. 135. Female, head. RGL Céreste 734.

Fig. 136. Male, terminalia, dorsal. MNHN Aix 1354.

Fig. 137. Male, terminalia, dorsal. MNHN Aix 516.

Fig. 138. Male, terminalia, ventral. MNHN Aix 516.

Fig. 139. Male, terminalia, dorsal. RGL Céreste 1010.

Fig. 140. Male, terminalia, ventral, RGL Céreste 602.

Fig. 141. Male, aedeagus and associated structures, RGL Céreste 1010. Fig. 142. Female, terminalia, ventral, RGL Céreste 499. Fig. 143. Female, terminalia, dorsal, RGL Céreste 379.

Terminalia (figs. 136–141): Epandrium dome-shaped. Gonostyli approximately 0.4 mm long, spoon-shaped, appearance very much depending on perspective. Aedeagus and associated structure as in fig. 141.

Female: Total length 5.0– 10.4 mm (N=142).

Head (fig. 135): Length 0.60 – 0.75 mm (N=4), width 0.77 – 1.10 mm (N=3). Brown. Compound eye relatively large and flat. Antenna cylindrical, flagellum 9-segmented.

Thorax: Length 1.4 – 2.4 mm (N=53). Brown. Haltere light brown.

Wing (fig. 133): Length 5.1 – 8.9 mm (N= 141), width 2.1 – 3.9 mm (N=40), length/width= 2.13 – 2.80 (N= 40). Oval, yellowish-brown, veins brown and relatively slender. Costa extends to half-way between apices of R4+5 and M1. Subcosta long, straight, running close to R1 for most of its length. R2+3 oblique, slightly curved, longer than in male. Pterostigma indistinctive. Crossvein M-Cu near base of CuA1. Wing vein measurements in Table 2.

Legs: Light brownish, slender. Fore tibia 1.6 – 2.1 mm (N=8).

Abdomen: Cylindrical, yellowish-brown.

Terminalia (figs. 142–143): Cerci small, apically knob-shaped.