Dissomphalus schubnelli, Falières & Nel, 2020

Falières, Elsa & Nel, André, 2020, First fossil of the extant flat wasp genus Dissomphalus Ashmead, 1893 (Hymenoptera: Bethylidae: Pristocerinae), Zoosystema 42 (15), pp. 207-213 : 208-211

Dissomphalus schubnelli n. sp.

( Figs 1-5 )

urn:lsid:zoobank.org:act:93883E6D-B5A9-4A8F-993B-E314FB6D6DB3

TYPE MATERIAL. — Holotype. ♂; MNHN.F. A71308 (PA 16948); MNHN.

TYPE STRATA. — Lowermost Eocene, Sparnacian, level MP7 of the mammal fauna of Dormaal.

TYPE LOCALITY. — Le Quesnoy, Chevrière, region of Creil, Oise department, France.

ETYMOLOGY. — Named after the entomologist Mr Thomas Schubnell.

DIAGNOSIS. — Hypopygium posteriorly triangular, outer median surface flat; clypeus wholly prominent forward, median lobe not well-outlined; dorsal pronotal area short; notauli well-developed and complete; metasomal tergum II longer than I; metasomal tergum II without posterolateral margin strongly incurved; tergal process with pair of dark round pits; no tergal process on tergum III; vein Rs&M of forewing rather oblique.

DESCRIPTION

Male

Body ( Fig. 1 ). 1.25 mm long, not depressed, not strongly foveolate; LFW 0.98 mm; head and mesosoma black; metasoma castaneous lightly iridescent, legs castaneous, antenna castaneous; wings hyaline.

Head ( Fig. 3 ). Smooth, not roughly sculptured; mandible with five apical teeth; five maxillary palpomeres, two or three hardly visible labial palpomeres; no spine on gena; clypeus wholly prominent forward, median lobe not well-outlined; antenna rather long, reaching mid part of metapectal-propodeal complex; 11 flagellomeres, cylindrical but basally narrowed; scape: 0.08 mm long × 0.04 mm wide, pedicel: 0.05 × 0.03 mm, F1: 0.05 × 0.03 mm, F2: 0.06 × 0.03 mm, F3: 0.06 × 0.04 mm, F4: 0.07 × 0.03 mm, F5: 0.05 × 0.04 mm, F6: 0.06 × 0.04 mm, F7: 0.05 × 0.04 mm, F8: 0.05 × 0.04 mm, F9: 0.05 × 0.04 mm, F10: 0.04 × 0.04 mm, F11: 0.08 × 0.04 mm; frons with numerous setae; dorsal part occipital carina present; eye glabrous; WH 0.28 mm; LH 0.34 mm; OOL 0.14; ocellar triangle equilateral.

Mesosoma ( Fig. 3A, B ). Dorsum smooth, not roughly sculptured but punctured; pronotum with anterior margin of disc apparently not carinate; dorsal pronotal area short; notauli well-developed and complete; parapsidal signum absent or strongly reduced; mesoscuto-mesoscutellar suture opened in its median part, with two lateral foveae, each linked to the suture by thin line; metanotum with medium region narrower than lateral regions, developed medially and overlapping mesoscutellum posteriorly; metanotal groove without foveae but with setae; metapectal-propodeal complex smooth with posterior carina and very small postero-lateral spines.

Forewing ( Fig. 2A ). Covered with microtricha and bordered with small setae; anterior border not angularly incurved anterior to pterostigma; costal vein present; 2r-rs&Rs vein long and as strong as other veins but not closing cell 2R1; strong vein cu-a more distal than vein M; vein Cu and vein A distal to cu-a; cells R, 1Cu, 2Cu closed; cells 1R1 and 1M absent; no basal stub of Rs+M; poststigmal abscissa of R1 very short, ghost first recurrent vein (FRR) and submarginal cell (cell SMC) present.

Metasoma ( Fig. 2B, C ). Short petiole; seven tergites, convex, partly covering sternites; posterolateral margin of tergite II without posterolateral margin strongly incurved, with pair

of lateral pits; tergite III without tergal process; hypopygium entire, posteriorly triangular.

Length of tergites. T1 about 0.05 mm, T2 0.12 mm, T3 0.07 mm, T4 0.08 mm, T5 0.07 mm, T6 0.06 mm, T7 0.05 mm.

Figures

FIG. 1. — Dissomphalus schubnelli n. sp., holotype MNHN.F.A71308, habitus: A, above; B, below; C, left side. Scale bars: 1 mm.

FIG. 2. — Dissomphalus schubnelli n. sp., holotype MNHN.F.A71308: A, wings; B, metasoma left view; C, metasoma right view, arrow tergal process. Scale bars: A, B, 0.5 mm; C, 0.2 mm.

FIG. 3. — Dissomphalus schubnelli n. sp., holotype MNHN.F.A71308: A, head and anterior part of mesosoma, arrow metanotum; B, head, arrow, clypeus. Scale bars: A, 0.4 mm; B, 0.2 mm.

FIG. 4. — Dissomphalus schubnelli n. sp., holotype MNHN.F.A71308, mandibles: A, front view; B, side view; ellipses, mandibles. Scale bars: 0.08 mm.

FIG. 5. — Dissomphalus schubnelli n. sp., holotype MNHN.F.A71308; arrow, hypopygium. Scale bar: 0.05 mm.