Plecia foersteri Théobald, 1937

Skartveit, John & Nel, André, 2017, Revision of fossil Bibionidae (Insecta: Diptera) from French Oligocene deposits, Zootaxa 4225 (1), pp. 1-83 : 42-44

Plecia foersteri Théobald, 1937

( Figs. 25 – 28, 119 – 122)

Plecia Försteri Théobald, 1937: 136 .

Plecia splendida Théobald, 1937: 137 Syn. n.

Plecia oviformis Théobald, 1937: 229 . Syn.n.

Plecia rubescens ( Oustalet, 1870) sensu Théobald 1937: 230 .

Material examined. Holotype (female) of Plecia foersteri NMB F1390. 4 paratypes (females) of Plecia foersteri NMB F 1391-1394. Lectotype (female, herein designated) of Plecia splendida NMB F1396. Paratype (female) of Plecia spendida NMB F1397. Paratype (female) of Plecia splendida MNHN B 23563. Holotype (female) of Plecia oviformis NMB F1384.

Théobald (1937: 137 and 231) described Plecia splendida with two “holotypes” (should be syntypes), one from Kleinkembs and the other one from Célas. We have studied the former but did not succeed in locating the latter, which may be lost. A species cannot have two holotypes, to clarify the identity of this species we have designated the one of the “holotypes” which could be found as a lectotype. The holotype of Protomyia rubescens is not recognizable, as was also commented on by Théobald (1937). He therefore (presumably) designated a “hypotypoide” for “ Plecia cf. rubescens ” (NHMB F1395/1), this specimen has no type status but is useful in clarifying Théobald’s concept of the species.

Additional material (28 females): NMB F1395/1, F1410, F1411/1-22, F1412, F2048, F2175, F2223, F2368.

Localities. Kleinkembs, Ronzon, Célas.

Diagnosis. A small-medium sized Plecia (wing length 4.9–7.8 mm). Antennal flagellum 8-segmented. Thorax black, abdomen brown, wing light brownish fumose.

Redescription. Male unknown. There is one male specimen (NHMB F 2090) in NHMB labelled as Plecia cf. rubescens , but it is highly uncertain if this is conspecific with the females.

Female: Total length 6.2 – 8.5 mm (N=23).

Head (figs. 120, 122): Length 0.59 – 0.78 mm (N=12), width 0.63 – 0.96 mm (N=15). Rather short and broad, oval, compound eye prominent. Antenna length 0.41 – 0.62 mm (N=8), rather short and thick, flagellum 8- segmented. Ocellar tubercle small.

Thorax: Length 1.7 – 2.7 mm (N=27), width 1.4 – 2.0 mm (N=16). Black. Sulci deep and distinctive. Haltere brown.

Wing (fig. 119): Length 5.4 – 8.0 mm (N=26), width 1.9 – 3.2 mm (N=23), length/width = 2.10 – 2.87 (N=23). Light brownish fumose, veins brown. Subcosta long and distinctive, humeral vein present. Costa extending to apex of R4+5. R2+3 slightly curved, oblique. Fork of M rounded. Pterostigma indistinctive. Wing vein measurements in Table 2.

Legs: Brown, slender.

Fig. 120. Female, head and thorax, dorsal. NMB F2423. Fig. 121. Female, terminalia, ventral. NMB F1411/13. Fig. 122. Female, head and thorax, NMB F1390.

Abdomen: Brown, spindle-shaped.

Terminalia: Cerci short and indistinctive.

Figures

FIGURE 25. Plecia foersteri, female. Holotype of Plecia försteri Théobald, NMB F 1390 FIGURE 26. Plecia foersteri, female. Holotype of Plecia splendida Théobald, NMB F 1396. FIGURE 27. Plecia foersteri, female. Holotype of Plecia oviformis Théobald, NMB F 1384. FIGURE 28. Plecia foersteri, female. “ Hypotypoide ” of Plecia rubescens (Oustalet) sensu Théobald, NMB F 1395 / 1. FIGURE 29. Plecia conica, male. Holotype of Plecia conica Théobald, NMB F 1398.