Dilophus cerestensis, NEL & LEGAL & COSTER, 2022

NEL, ANDRÉ, LEGAL, STÉPHANE & COSTER, PAULINE, 2022, A new species of the March fly genus Dilophus Meigen, 1803 (Diptera: Bibionidae) from the Oligocene of Provence (France), Palaeoentomology 5 (4), pp. 347-353 : 348-349

Dilophus cerestensis sp. nov.

( Figs 1–3 ) urn:lsid:zoobank.org:act:9B06E4BA-CE35-4FC7-B71AF56D20F3D561

Material. Holotype specimen PNRL 2243 (Coll. Nel, imprint of a complete fly fossilized in dorsal view, male), stored in the Musée of Palaeontology , Réserve Géologique du Lubéron, Apt, France.

Etymology. Named after the type locality Céreste.

Diagnosis. Wing crossvein r-m quite shorter than basal part of Rs; posterior margin of sternum 9 without emargination on each side of broad median one; tergum 9 with an obtuse angled V-shaped posterior emargination; harpagones very broad, nearly right-angled in middle and narrowing gradually towards conical acute apex.

Type locality and horizon. South of the village of Céreste , Alpes-de-Haute-Provence, France, Early Oligocene, ‘ Calcaire de Campagne-Calavon’ Formation.

Description. Total body length 8.0 mm. Head black, with long setae visible laterally, 1.3 mm long, 1.1 mm wide; compound eyes 0.2 mm long, situated in anterior half of head; occiput elongate; right maxillary palp visible, with third palpomere larger than others; antenna short and stocky, 11 antennomeres. Thorax 2.2 mm long, 1.2 mm wide; mesonotum black, with at least two frontal spines and two in more posterior positions. Wing hyaline, 5.8 mm long, ca. 1.6 mm wide; pterostigma small, oval and dark brown, R-veins dark brown, vein M colorless; Costa extending to apex of R 4+5; crossvein r-m 0.1 mm long, quite shorter than basal part of Rs (0.3 mm long); distal parts of vein M and posterior half of wing not visible. Halters not visible. Legs yellowish-brown, without discernible pilosity, tarsi black; fore femur strong, 1.4 mm long, tibia rather stout, 0.9 mm long, with an oblique median row of two-three spines and an apical row of three spines, tarsus 2.9 mm long; mid femur ca. 1 mm long, mid tibia 1.2 mm long, tarsus 2.0 mm long; hind femur 2.4 mm long, dilated distally, tibia 2.1 mm long, strongly dilated distally, tarsus 2.2 mm long, basal tarsomere enlarged, nearly as wide as tibia. Abdomen cylindrical, dark brown, 4.0 mm, 1.0 mm wide, covered with a light, rather long, sparse pilosity, visible laterally. Hypopygium: posterior margin of sternum 9 without emargination on each side of broad median one; tergum 9 with an obtuse angled Vshaped posterior emargination. Harpagones very broad, nearly right-angled in middle and narrowing gradually towards conical acute apex.

Figures

FIGURE 1. Dilophus cerestensis sp. nov., holotype PNRL 2243. Photograph of habitus. Scale bar = 2 mm.

FIGURE 2. Dilophus cerestensis sp. nov., holotype PNRL 2243. Photographs. A, Wing. B, Head, thorax, fore and mid legs. Scale bars = 2 mm.

FIGURE 3. Dilophus cerestensis sp. nov., holotype PNRL 2243. Photograph of abdomen and hind leg. Scale bar = 2 mm.