Lonchopterites burmensis, 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

Lonchopterites burmensis , new species

Figures 2 , 26

DIAGNOSIS: Distinguished from the type species by the ocellar setae lying outside of the ocellar triangle; lack of inner vertical setae; base of arista slightly dorsal to apex of basal flagellomere (vs. on apex); face with smaller pair of setae lateral to vibrissae; vein R 1 slightly shorter (0.28× wing length, vs. 0.40×). Based on unique male specimen.

DESCRIPTION: Head: [(Seen largely in just dorsal view), total width ca. 280 µm. Eyes of male dichoptic, widely separated (150 µm near middle of frons); mesal margins diverging posterioad; dorsoventral facets undifferentiated; eye completely bare, fine setae lacking. Frons: Broad, without median furrow; pair of well-developed inclinate interfrontals present, bases very close to bases of antennae; distance between interfrontals approximately equal to that of ocellars. One pair of fronto-orbital setae present, slightly lateroclinate and reclinate; setal base very close to inner margin of eye. Interfrontal, fronto-orbital, and ocellar seta approximately equal in length. Ocellar setae reclinate and slightly lateroclinate, bases situated lateral to anterior ocellus, not within ocellar triangle. Inner vertical setae apparently lacking; outer vertical setae lateroclinate, length ca. 1.3× that of fronto-orbital. Postocellar setae lacking. Row of 3–4 stiff, inclinate postoccipital setae present on each side. Pair of large, projecting facial vibrissae present; vibrissae slightly larger than orbitals; slightly smaller seta lateral to vibrissa. Antenna: Porrect; scape small, cylindrical, bare; pedicel slightly conical, asymmetrical, distal rim with fine setulae (especially mesal margin), pedicel without conus (visible through cleared cuticle); basal flagellomere short, slightly asymmetrical and short, with fine setulae; base of arista situated slightly dorsal to apex of basal flagellomere; arista with two articles, basal one minute and ringlike, arista overall long and virtually bare, very faintly microsetulose, length ca. 220 µm (base of antenna 100 µm). Mouthparts: not visible; oral margin protruding slightly. Thorax: Fairly long, ca. 0.50 mm, ca. 0.30 mm at deepest portion; dorsally (scutum) bristly, flattened posteriad; subscutellum and anatergite not exposed. Acrostichals and dorsocentrals long, suberect, in rows extending entire length of scutum; acrostichals in two rows of 9–10 setae each (anterior setae thicker); row of slightly longer dorsocentrals lateral to this, posterior dorsocentrals more than 2× length of anterior ones. Pleural area obscured, sutures not visible, devoid of setae. Postpronotal lobe with 3 fine, long setae; notopleural area with 2 long, fine setae. Prescutellum absent; apex of scutellum slightly upraised; two pairs of scutellar setae, one apical pair (upright and cruciate), one subapical pair. Wing: Fairly slender, width 0.42× the length, length 0.85 mm, apex slightly pointed; overall faintly fuscous, membrane entirely covered with minute microtrichia; no pterostigma. No setae on any veins except C; large prehumeral costal seta absent. Costal vein terminating at apex of R 4+5, having row of ca. 25 long spinules on leading edge, no setae or spinules on lateral surface. Sc short, apically evanescent. R 1 very short, 0.28× the wing length; R 2+3 slightly sinuate, 0.82× length of wing; R 4+5 ends at pointed apex of wing, this vein distinctly thicker than others; M veins very faint, forked, length of fork 0.52× length of wing, stem of fork very faint, grading basally to nebulous; CuA 1 complete, reaching wing margin, slightly curved; cell bm not apparent, cell cup faint (M margin nebulous); vein A 1 present but incomplete. Crossvein br-m, bm-cu, and dm-cu absent; anal lobe present but small, with marginal fringe of ca. 12 fine, long setae; alula absent. Legs: Male protarsomeres lacking denticles; metatarsomeres lacking rows of pali- sade setae; pulvillus well developed, empodium setiform; metabasitarsomere slightly expanded in width, broader than any other tarsomeres, slightly shorter than metatarsomere 2. Apex of tibia with pair of short, stout, curved, spinelike setae on ventral margin; dorsal margin with erect, fine preapical seta. Abdomen: Abdominal muscle plaques apparently absent; spiracles not observable; six large tergites visible (including epandrium); segmentation of basal tergites not visible. Male Terminalia: Well developed, ventroflexed; cercus terminal; epandrium tucked ventrally, with comb of ca. 10 fine setae on medial margin; two rows of setae forming basketlike structure; surstylus not visible (possibly absent). Phallus short, terminal, spinelike. Female Terminalia: Unknown.

SPECIMENS EXAMINED: Holotype, male, AMNH Bu-SE15, from mid-Cretaceous of northern Myanmar, Kachin Province. Deposited in AMNH. In excellent condition.

ETYMOLOGY: In reference to the source country.

Figures

FIG. 2. Lonchopterites burmensis, n. sp. (Lonchopteroidea), holotype male AMNH Bu-SE15, in mid-Cretaceous amber from Myanmar. A. Lateral habitus. B. Lateral view of posterior half, with wing.

FIG. 26. Lonchopterites burmensis, n. sp. (Lonchopteroidea), in mid-Cretaceous amber from Myanmar. A–D. holotype male AMNH Bu-SE15. A. Lateral habitus. B. Right metatarsus. C. Terminalia, left lateral view. D. Antennae, dorsal view. E. Head, paratype JZC Bu-1578.