Pseudomicrodon Hull

Reemer, Menno & Stahls, Gunilla, 2013, Generic revision and species classification of the Microdontinae (Diptera, Syrphidae), ZooKeys 288, pp. 1-213 : 58-59

Pseudomicrodon Hull Figs 307-320

Pseudomicrodon Hull, 1937a: 24. Type species: Microdon beebei Curran, 1936: 4, by original designation.

Description.

Body length: 7-9 mm. Slender flies with long antennae and petiolate abdomen. Head a little wider than thorax. Face more convex or straight in profile; narrower than to as wide as an eye. Lateral oral margins weakly produced. Vertex convex and shining; sparsely pilose, sometimes bare on anterior half. Occiput ventrally narrow, dorsally strongly widened. Eye bare or with very short and sparse pile. Eye margins in male converging at level of frons, with mutual distance 1-2 times width of antennal fossa. Antennal fossa about as wide as high to 1.5 times as wide as high. Antenna longer than distance between antennal fossa and anterior oral margin; basoflagellomere shorter to longer than scape, oval; bare. Postpronotum pilose. Scutellum semicircular; with or without calcars. Anepisternum sulcate; entirely pilose or widely bare medially. Anepimeron entirely pilose. Katepimeron flat to convex; usually with wrinkled texture; bare. Wing: vein R4+5 with posterior appendix; vein M1 perpendicular to vein R4+5; postero-apical corner of cell r4+5 widely rounded to rectangular, with or without small appendix; crossvein r-m located between basal 1/6 to 1/3 of cell dm. Abdomen elongate, more than three times as long as wide, constricted, with narrowest point between halfway tergite 2 and transition between tergites 2 and 3. Tergites 3 and 4 fused. Sternite 1 pilose or bare. Male genitalia: phallus furcate near apex, with dorsal process long and whip-like, ventral process very short; epandrium with ventrolateral ridge.

Diagnosis.

Vein R4+5 with posterior appendix. Vertex convex and shining, sparsely pilose to bare. Abdomen petiolate, except parallel-sided in Pseudomicrodon biluminiferus Hull, but tergite 2 distinctly dorsoventrally flattened in that species.

Discussion.

Among Microdontinae with a petiolate abdomen, Pseudomicrodon species are recognized by their convex and shining vertex. Microdon biluminiferus Hull, 1944 is the only included species without a petiolate abdomen. Instead, the abdomen is parallel-sided, but in lateral view appears constricted because of the dorsoventrally flattened segment 2. This species is assigned to Pseudomicrodon based on the convex vertex and the morphology of the male genitalia (Figs 319, 320), combined with the results of the phylogenetic analysis of morphological characters ( Reemer and Ståhls in press).

At present, the basis for distinguishing Ceriomicrodon , Pseudomicrodon and Rhopalosyrphus is narrow. The groups are certainly related, but as presently defined it is doubtful whether they are monophyletic, considering the variation in several morphological characters.

Keiser (1971) described Pseudomicrodon elisabethae from Madagascar. This species is here included in Paramixogaster . Cheng and Thompson (2008) mention the similarity of the South African taxon Microdon illucens Bezzi, 1915 to Pseudomicrodon , which is here also included in Paramixogaster .

Diversity and distribution.

Described species: 15. Neotropical.