Gujaratmyia rotunda Bickel, 2022

BICKEL, DANIEL J., MARTIN, JOHN, AGNIHOTRI, PRIYA & SINGH, HUKAM, 2022, Dolichopodidae (Diptera) from the Eocene amber deposits of Cambay and Kutch Basins, India, Palaeoentomology 5 (5), pp. 475-486 : 482-483

Gujaratmyia rotunda Bickel sp. nov.

( Fig. 4A–C )

Type material. Holotype: ♂, INDIA: Gujarat: Tadkeshwar Lignite Mine, Lower Eocene strata of the Cambay Shale Formation , 21°21.400′N, 73°4.532′E. 7–12/I/2009, D. Grimaldi & P. Nascimbene, Tad-67 ( AMNH).

Etymology. The specific epithet is from Latin, rotundus, meaning round or spheroidal, as reflected in the specimen’s rounded compact appearance.

Diagnosis. As for genus.

Locality and horizon. Cambay and Kutch basins, Gujarat State, India; Eocene.

Description. Male. Length: 1.1 mm; wing 0.6 × 0.4 mm.

Head. Rather large, ovate in anterior view; dorsal postcranium strongly concave; vertex and frons not clearly visible, face as narrow band separating eyes; eye facets uniform; clypeus conformable with eye, not projecting anteriorly; palp and proboscis brown; scape and pedicel short; postpedicel rounded, but arista distinctly dorsal, about as long as head height; ventral postcranium bare.

Thorax. Dark brown, mostly obscured, posterior mesonotum apparently flattened but not clearly visible; only one dorsocentral seta visible, whiteish coloured.

Legs. Brownish; I: 2.1; 1.8; FI with weak subapical pv seta; TI mostly bare, but with subapical pv seta; II: 2.5; 2.7; 0.8/0.5/ 0.4/0.3/0.5; FII with distinct anterior preapical seta at 4/5; TII with strong ad seta at 1/3; III: 2.8; 3.1; 0.6/0.5/0.4/0.3/0.4; FIII with distinct anterior preapical seta at 4/5; TIII with row of short dorsal setae, and with stronger subapical dorsal seta; other setation obscured.

Wings ( Fig. 4B, C ). Hyaline; rather broad and short; R 1 terminating in basal third of costa; R 2+3 joining costa near 2/3; R 4+5 diverging from M 1 near base, and becoming almost subparallel with M 1 beyond level of dm-m crossvein to join costa at 7/8, M 1 joining margin slightly behind wing apex; CuAx ratio: 0.5; calypter with fan of short black setae; halter with short yellow stalk and large dark brown club.

Abdomen. Tergites dark brown with short yellowish setae (strong marginal setae on tergites not evident); five tergites visible, and somewhat dorsoventrally flattened; hypopygium forming ovoid cap over apex of abdomen, and with short whitish distal appendages.

Female. Unknown.

Remarks. Gujaratmyia rotunda is a tiny species known from an obscured male that is covered with streaks of apparent fungal hyphae. On this specimen, the right wing appears inflated and almost balloon-like ( Fig. 4B ), possibly from gases of decomposition filling the lumen between the two wing layers.

Figures

FIGURE 4. Gujaratmyia rotunda sp. nov. A, Male habitus, left lateral (GIAM-002). B, Male habitus, right lateral (GIAM-002). C, Male wing dorsal (GIAM-002). Rajpardia grimaldii sp. nov. D, Male habitus, left lateral (GIAM-013). E, Male postabdomen, left lateral (GIAM-013). F, male habitus, right ventral (GIAM-013). Dolichopodidae: Medeterinae. G, Male habitus, left dorsal