Mermerizon Reemer

Reemer, Menno & Stahls, Gunilla, 2013, Generic revision and species classification of the Microdontinae (Diptera, Syrphidae), ZooKeys 288, pp. 1-213 : 37-38

Mermerizon Reemer gen. n. Figs 157-162

Type species:

Mermerizon inbio spec. n. Type locality: Costa Rica.

Description.

Stingless bee mimicking flies with moderately long antennae and elongate oval abdomen. Head slightly wider than thorax. Face convex; narrower than an eye. Lateral oral margins not produced. Vertex flat. Occiput ventrally narrow, dorsally widened. Eye bare. Eye margins in male parallel, not converging at level of frons, with mutual distance 3-4 times as large as width of antennal fossa. Antennal fossa about as wide as high. Antenna shorter than (may be almost as long as) distance between antennal fossa and anterior oral margin; basoflagellomere slightly shorter to longer than scape, oval; bare. Postpronotum pilose. Scutellum semicircular; without calcars. Anepisternum without sulcus; pilose on dorsal half, bare on ventral half. Anepimeron pilose on dorsal half, bare on ventral half. Katepimeron convex; 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 around basal 1/10 of cell dm. Abdomen oval, 2 to 3 times as long as wide. Tergites 3 and 4 fused. Sternite 1 pilose. Male genitalia: phallus slightly bent dorsad, furcate near apex, with dorsal process at least twice as long as ventral process; hypandrium with bulb-like base; epandrium without ventrolateral ridge.

Diagnosis.

Vein R4+5 with posterior appendix. Postero-apical corner of cell r4+5 rectangular, with small appendix. Postpronotum pilose. Propleuron bare. Membrane between sternites 2 and 3 less wide than sternite 2. Abdomen oval. Anepisternum bare on ventral half, pilose on dorsal half, except for small median bare part on dorsal half. Anepimeron bare on ventral half. (Male: eye margins parallel at level of frons, not converging).

Discussion.

The species of this genus are obvious mimics of stingless, Trigona -like bees in their tawny colouration and long pilose hind tibiae. At first sight they may be confused with Hypselosyrphus , Rhoga , or Stipomorhpa . From the first two genera, Mermerizon can be distinguished by the presence of a posterior appendix on vein R4+5, from Stipomorpha by the absence of a wide membrane between sternites 2 and 3. A presently undescribed Argentinian species lacks the long pilosity of the hind tibiae and does not seem to mimic these bees. Instead, it resembles Paragodon Thompson, 1969 and Surimyia Reemer, 2008 in general habitus, but is easily told apart by the presence of a posterior appendix on vein R4+5 and the male genitalia, which are very similar to those of the other two Mermerizon species.

Diversity and distribution.

Described species: 1. Descriptions of two additional species are in preparation by the first author. Neotropical (presently known from Costa Rica and Argentina).

Etymology.

The generic name is derived from the ancient Greek verb mermerizo, meaning 'to deliberate’ or 'to ponder’. This name was chosen because it took some deliberation before making the decision that a new genus was to be erected for the involved species. The name is to be treated as masculine.