Proironia burmitica, Grimaldi, 2018

Grimaldi, David A., 2018, Basal Cyclorrhapha In Amber From The Cretaceous And Tertiary (Insecta: Diptera), And Their Relationships: Brachycera In Cretaceous Amber Part Ix David A. Grimaldi, Bulletin of the American Museum of Natural History 2018 (423), pp. 1-97 : 1-97

Proironia burmitica , new species

Figures 14 , 42

DIAGNOSIS: Distinguished from its congener as given in the diagnosis above.

DESCRIPTION: Head: Depth/width 0.92. Occiput near posterior margin of eyes rimmed with row of stiff, whitish setae that point backward. Eyes: Bare; meeting dorsally (or virtually so) for distance ca. 8 facets; no differentiation of facets; medial edges emarginate around eyes. Frons: A barely exposed sliver, dark brown; faint median furrow present on dorsal sliver of frons; medial edges emarginate around antennae; no ocellar, postocellar, or frontal setae present. Ocellar triangle raised; lateral/posterior ocelli closer to each other than to anterior ocellus. Face below antennae very short; oral cavity partly exposed anteriorly; clypeus narrow, Ω-shaped; oral margin not rimmed by protruding membrane. Vibrissa absent. Antenna: Bases very close, scape small, short and funnel shaped; pedicel with triangular lobe inserted into lateral and mesal surfaces of basal flagellomere, lobe not quite 0.5× length of basal flagellomere; basal flagellomere subcircular, laterally flattened, dorsal third light, ventral 2/3 darker, brown; arista terminal, with 2 small basal articles, length of each article ca. 2× its width; arista bare. Mouthparts: Compact, not protruding beyond level of basal flagellomeres (as preserved). Palp small, globular, light in color; labellum small, laterally flattened, extended slightly beyond level of palps. Occiput dark brown, dorsal portion deeply concave. Thorax: Depth ca. 0.95× the length; scutum convex in profile, slightly flattened on top. Scutum with scattered, very fine, very decumbent setulae (most visible laterally). One pair of dorsocentral setae present, stout and short, length slightly less than length of scutellum; very close to anterior margin of scutellum. Scutellum with 4 pairs of short, stout setae, apical pair upright with tips crossing; 4 stout, stiff notopleural setae, located just above pleural cleft and anterior to transverse suture; 2 postalar setae; prescutellum well developed, lenticular. Wing: Width/length 0.48, apex slightly acute, anterior (costal) edge virtually flat; membrane entirely glassy, no microtrichia (even near wing margin). Vein C ends at apex of R 4+5. Sc long, fused to R 1 for 0.77× its length, both veins free at base and apex. R 2+3 and R 4+5 long, nearly parallel; crossvein br-m very short, cell d L/ W 3.0, apex square (crossvein dm-cu perpendicular to longitudinal veins); M 1 and M 2 joined at base by stem connecting to cell d, stem 0.21× length of stem + fork; cell cup narrow, apex acute. A 1, A 2, anal lobe and alula not entirely visible. Legs: Slender, brown, pro- and mesocoxae with sparse brush of ca. 10 fine, long setae ventrally (metacoxa bare); femora without macrosetae. Protibia with thick, short, preapical seta on dorsal surface, ca. 8 short, transverse, ctenidial-like rows of fine setulae, tarsomeres 1–4 with short ctenidial combs. Mesofemur without longitudinal groove on ventral surface. Mesotarsomeres 1–4 with 2 longitudinal rows small, stout setae on ventral surface. Metatarsus same as protarsus. Pretarsi with claws well developed, pulvilli shorter than claws; empodium setiform, fine and projecting. Abdomen (Male): Relatively short, base thick; with fine, short, erect, pilelike setulae on tergites, no macrosetae. Tergites large, covering most of lateral surface of abdomen; dark brown. Six well-developed tergites visible (sternites not exposed); narrow pleural membrane exposed. Epandrium large, bulbous, ventroflexed, tucked under tergite 7. Male Terminalia: Not exposed.

SPECIMENS EXAMINED: Holotype, male, AMNH Bu-Se2/8, in Burmese amber. Complete, very well preserved.

ETYMOLOGY: In reference to burmite, a common term for Burmese amber.

Figures

FIG. 14. Proironia burmitica, n. gen., n. sp. (Ironomyiidae), holotype male in Burmese amber, AMNH Bu-SE2/8. A. Right lateral habitus. B. Head and thorax, dorsal. C. Head, right lateral. D. Portion of thorax. E. Legs. F. Posterior half of abdomen.

FIG. 42. Proironia burmitica, n. gen., n. sp. (Ironomyiidae), holotype male in Burmese amber, AMNH Bu-SE2/8. A. Wing. B. Dorsum of head and thorax. C. Oblique posterior view of head. D. Hind leg, mesal view (not showing tarsomeres 4 and 5). E. Midtarsus, dorsal view.