Prosyrphus thompsoni Grimaldi 2018, new species
Creators: name: Grimaldi, David A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Phoridae
Prosyrphus
Prosyrphus thompsoni

description: Prosyrphus thompsoni, new species
Figures 21, 52
DIAGNOSIS: As for genus, by monotypy.
DESCRIPTION: (male only). Body stout, compact. Head: Broad, slightly broader than thorax, faintly compressed dorsoventrally. Eye completely bare of setulae; large, occupying all of dorsal and lateral surfaces and much of venter; dorsal facets slightly larger than ventral ones, no discrete dividing line; male holoptic for entire length of frons. Frons obscured (presence/ absence of median furrow, interfrontal and fronto-orbital setae not determinable). Ocelli on low tubercle, with two small pairs of stiff ocellar setae. Vertical setae absent; postocular setae fine, small; occiput faintly concave, with scattered fine setulae. Face relatively broad, ~0.3× width of head; bare, slightly swollen in middle; anterior tentorial pits deep, vertical and slitlike, close to eye margin. Oral cavity small, entirely ventral; vibrissa and genal setae absent. Antenna: Scape small, bare, slightly asymmetrical; pedicel asymmetrical, with tonguelike lobe inserted into mesal surface of basal flagellomere; arista dorsal; basal flagellomere reniform; arista with two minute articles at base, apical article long, flagellate, tapered to very fine apex, completely bare of micropubescence. Mouthparts: Clypeus minute; oval; isolated, not articulating with labrum; palp small, slender; proboscis, small, short, slender; labrum slender; labellum small, arely wider than rest of proboscis.
Thorax: Short, broad, deep in lateral view; scutum rounded but not arched. Acrostichals numerous, scattered, not in rows. Dorsocentral macrosetae present, in 2 prescutellar pairs, none in serial rows. Macrosetae: 2 supraalar; 5 notopleural; 4 pairs of scutellars, longest ones near center, disk of scutellum with setulae. Wing: Broad, length/width 2.0, tapered apicad; hyaline, slightly darkened between apices of Sc and R 1; membrane with dense, very fine microtrichia, less dense in cell Sc; pterostigma absent. Prehumeral costal seta(e) small, large macrosetae absent; vein C with minute spinules; end of C not visible (wing tips lost at surface of amber); Sc long, ~0.6× length of wing; R 1 long, running close to base of Sc, slightly diverging apicad; sc-r appears absent; R 2+3 straight, base weak; R 4+5 straight; spurious vein absent; cell dm large, cleaver shaped; cell rm long, r-m at same level as apex of Sc; cell bm narrow; crossvein dm-cu close to wing margin, separated by distance ¾ length of dm-cu; M 1 -M 2 forked, tip of M 1 not reaching wing margin; tip of CuA 1 not reaching wing margin; CuA 2 curved, A 1 straight; cell cup large, much longer than apical vein; anal lobe large, alula relatively small. Halter stem slender.
Legs: Setose, relatively short, slender; femora longer than respective tibia, profemur with ventral row ~7 long setae, setal lengths about equal to femur width. Mesotibia with short, stout ventroapical spur. Basitarsomeres longest of all tarsomeres; pulvillus ~0.7× length of claw; empodium not observable (perhaps minute); claw ~0.5× length of tarsomere 5.
Abdomen: Short, stout; anterior 4 tergites large, with short, scattered setulae, laterally curved but not contacting sternites (pleural membrane exposed). Five large sternites visible, anterior and posterior margins in contact; with short, scattered setulae. Male Terminalia: Segments 6, 7, and 8 asymmetrical, ventroflexed; sternites 5 and 6 exposed dorsally; sternite 8 bulbous, terminal; epandrium triangular, shifted to left; surstyli large, heavily setose; cerci symmetrical, setose, hidden beneath sternite 8, point forward.
Female Terminalia: unknown.
SPECIMENS EXAMINED: Holotype, male AMNH Bu-SE03 The specimen is in beautiful condition, very well preserved, and virtually complete (missing only the tips of the wings).
ETYMOLOGY: Patronym for F.C. Thompson, for his many contributions to the systematics of Syrphidae and Diptera in general.
description: Published as part of 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, pp. 1-97 in Bulletin of the American Museum of Natural History 2018 (423) on pages 1-97, DOI: 10.1206/0003-0090-423.1.1, http://zenodo.org/record/4613008