Laetodon Reemer

Reemer, Menno & Stahls, Gunilla, 2013, Generic revision and species classification of the Microdontinae (Diptera, Syrphidae), ZooKeys 288, pp. 1-213 : 33-34

Laetodon Reemer gen. n. Figs 132-135

Type species:

Microdon laetus Loew, 1864: 74, by original designation. Type locality: Cuba.

Description.

Body length: 6-9 mm. Small, metallic green to blue flies, with long antennae and oval abdomen. Head about as wide as thorax or slightly wider. Face convex; narrower than an eye. Lateral oral margins weakly produced. Vertex flat. Occiput ventrally narrow, dorsally widened. Eye pilose. Eye margins in male converging at level of frons, with mutual distance 2 to 4 times as large as width of antennal fossa. Antennal fossa about as wide as high. Antenna about as long as to longer than distance between antennal fossa and anterior oral margin; basoflagellomere longer than scape, oval; bare. Postpronotum pilose. Scutellum semicircular; with calcars, which may be spatulate (widened and dorsoventrally flattened). Anepisternum weakly sulcate; pilose anteriorly and posteriorly, widely bare in between. Anepimeron entirely pilose. Katepimeron convex; smooth; bare. Wing: vein R4+5 with posterior appendix; vein M1 perpendicular to vein R4+5; postero-apical corner of cell r4+5 rectangular, with small appendix; crossvein r-m located between basal 1/6 to 1/5 of cell dm. Abdomen oval, about 1.5 to 2 times as long as wide. Tergites 3 and 4 fused. Sternite 1 pilose or bare. Male genitalia: phallus unfurcate, projecting slightly beyond apex of hypandrium; hypandrium with basal part bulb-like; epandrium without ventrolateral ridge; surstylus shallowly furcate, with long posterior process.

Diagnosis.

Vein R4+5 with posterior appendix. Postpronotum pilose. Abdomen oval. Anepisternum widely bare medially. Propleuron pilose. Postero-apical corner of cell r4+5 rectangular. Eye pilose.

Discussion.

The species included in this genus used to be placed in Microdon ( Thompson 1981b). Morphology of the male genitalia, however, is quite distinct from that of Microdon as defined in the present paper: the phallus is short and unfurcate, the epandrium lacks the ventrolateral ridge. Based on these morphological differences and the phylogenetic results of Reemer and Ståhls (in press), Laetodon is here erected as a new genus. See Chrysidimyia for discussion on possible relationships with that genus.

Diversity and distribution.

Described species: 5. Nearctic (4 species) and Neotropical (1 species).

Etymology.

The generic name is composed of laetus and odon, with the first part derived from Microdon laetus Loew, 1864 (the type species of the genus), and the latter used as a suffix derived from Microdon .