Burmacyrtus rusmithi Grimaldi & Hauser

Grimaldi, David A., Arillo, Antonio, Cumming, Jeffrey M. & Hauser, Martin, 2011, Brachyceran Diptera (Insecta) in Cretaceous ambers, Part IV, Significant New Orthorrhaphous Taxa, ZooKeys 148, pp. 293-332 : 307-309

Burmacyrtus rusmithi Grimaldi & Hauser sp. n. Fig. 6

Diagnosis.

As for genus.

Description.

Wing length approximately 1.4 mm, body length approximately 2.0 mm. Head: Rounded, spherical. Male eyes bare of setulae, frontally holoptic [dorsum of head not visible], occupying most of head capsule, ventromesal margins of eyes diverging around clypeus; facets in ventral portion of eye not differentiated in size; posteroventral margin of eye with shallow emargination. Basal portion of flagellum small, ovoid; stylus long and very slender, length c. 2 × that of basal portion; apex of stylus with pair of minute setulae. Labellum well developed; palps not evident. Postocciput with dense, fine pilosity. Thorax: Cervical region elongate, but not comprised of elongate postpronotal lobe (which protrudes slightly from anterior surface of scutum); cervical region connected anteroventrally to thorax. Thorax deep. Dorsal surface of mesoscutum and scutellum with dense, fine pilosity. Legs slender, metafemur longest; without spines, bristle, or tibial spurs; tibial and tarsal setulae not in regular rows. Apical portions of tibiae not distinctly broadened. Pretarsal claws large; pulvilli large, mediolobus absent [if setiform empodium present, not visible]. Wing short, with broadly rounded apex and narrow base; surface devoid of microtrichia, with fine wrinkling throughout. Vein C circumambient, though thinner past apex of M1; small hump in C midway along length of Sc. Sc complete, length ca. 0.4 × that of wing (a thin, faint, incomplete, and apparently spurious vein runs parallel and very close to Sc). Vein R1 short, length approximately 0.5 × length of stem of R; R1 and C thickened where they meet. Stem of Rs short, length approximately 0.5 × that of R1; Rs and where it meets M thickened. R4-R5 apparently a vestigial fork (R4 incomplete, not connected to R5). Cells r4+5 and m3 absent; cell d present, large; length of cell d 0.3 × that of wing. Cells br and bm present, separated by well developed basal portion of M. Veins M1, M2, M3 present, originating from apex of cell d. Veins CuA1 and CuA2 present, originating from apex of cell bm. Vein A present, but short and vestigial (cell cup absent). Alula and calypter well developed, each with fine wrinkling; calypter approximately 2 × diameter of alula. Halter apparently dark. Abdomen: larger than thorax; sternites well developed, glabrous, without setulae or punctures. Tergites large, with dense, file pilosity; each setula situated in minute puncture. Male genitalia: epandrium well developed, shallow; cerci slender and apically pointed; everted, distal portion of phallus bulbous; subapical portion flanked by pair of flat, setulose lobes. Spiracles not visible.

Type.

Holotype, Male, AMNH Bu-RS1, in Burmese amber. The holotype is in excellent condition, though only the ventral and lateral portions are visible (the dorsal surface is obscured by the depth and curvature of the amber). The amber is clear yellow and the fly lies on an internal surface plane that contains bubbles and stellate trichomes. The original piece was drop-shaped, 10 × 16 mm, and contained a small spider, cecidomyiid midge, and berothid lacewing. These inclusions were separated from the fly.

Etymology.

Patronym, for Dr. R.D.A. (Ru) Smith, who generously donated the specimen to the AMNH from his personal collection.