Mermerizon mesmerizus, Reemer, Menno, 2013

Reemer, Menno, 2013, Taxonomic exploration of Neotropical Microdontinae (Diptera: Syrphidae) mimicking stingless bees, Zootaxa 3697 (1), pp. 1-88 : 41-43

Mermerizon mesmerizus spec. nov.

Figs 121–123 , 126 .

Studied type specimens. HOLOTYPE. ARGENTINA. Male. Label 1: " ARGENTINA. Catamarca / Prov., 9 km N La Merced. / 28°06.43’S- 65°36.96’W / Mal. trap in damp ravine / 24.X-12.XI. 2003. 1041 m / M.E. Irwin & F.D. Parker”. Coll. RMNH (preliminary deposition, to be deposited in appropriate Argentinian collection later).

PARATYPES: Two males from same locality and date as holotype. One in coll. RMNH, one in coll. CSCA.

Description (based on holotype, unless stated otherwise)

Adult male Body size: 5 mm.

Head. Face occupying about 1/3 of head width in frontal view; yellow; yellow pilose. Gena yellow. Frons and vertex brown; yellow pilose. Occiput brown; yellow pilose dorsally, white pilose ventrally. Eye bare. Antennal fossa about as high as wide. Antenna black; antennal ratio approximately as 2:1:4.

Thorax. Scutum black, with margins widely yellow; entirely yellow pilose. Postpronotum and postalar callus yellow; yellow pilose. Scutellum semicircular, without calcars; yellow, except black ventrolaterally; yellow pilose. Anepisternum convex, without sulcus; brown anteriorly, yellow posteriorly; yellow pilose anterodorsally and posterodorsally. Anepimeron brown with yellow margins; yellow pilose. Katepisternum brown; yellow pilose dorsally. Katepimeron yellow; bare. Katatergum yellow; long yellow microtrichose. Anatergum yellow; short yellow microtrichose. Calypter grey. Halter yellow.

Wing: hyaline, with costal cell grey and with vaguely defined greyish transverse fasciae from pterostigma to bm-cu, from appendix of R4+5 to dm-cu and at M1; microtrichose, except bare on 1st costal cell, basal 2/3 of cell br and narrowly along anterior margin of cell cup.

Legs: [Front legs missing in holotype. Description partly based on paratypes.] Femora black, except narrowly yellow at apex; black pilose, except partly yellow pilose basally. Tibiae yellow, except hind femur black at apical 1/ 3; yellow pilose. Tarsi black; black pilose. Coxae and trochanters blackish brown; pale pilose.

Abdomen. Tergites brown, with lateral and posterior margins a little paler. Tergites 1 and 2 yellow pilose. Tergite 3 black pilose on anterior 2/3, yellow pilose on posterior 1/3. Tergite 4 black pilose on anterior 1/3 and laterally, yellow pilose medially and posteriorly. Sternites brownish. Sternite 1 bare. Sternite 2 yellow pilose. Sternites 3-4 black pilose. Genitalia as in fig. 126.

Female. Unknown.

Etymology. The specific epithet mesmerizus is a Latinized adjective derived from the English ‘mesmerizing’, which means ‘hypnotizing’ in the sense of ‘fascinating’.

Diagnosis. Body size 5-6.5 mm. Unlike the other two known species of Mermerizon, this is not clearly a stingless bee mimic. The pilosity of the hind tibia is short and appressed. The wings have a pattern of vaguely defined greyish transverse fasciae.

Distribution. Only known from northern Argentina.

Figures

FIGURES 113 – 123. 113 – 117. Mermerizon inbio male (holotype). 113. habitus dorsal; 114. habitus lateral; 115. head frontal; 116. head lateral; 117. wing. 118 – 120. Mermerizon mellosus male (holotype). 118. habitus dorsal; 119. habitus lateral; 120. head frontal. 121 – 123. Mermerizon mesmerizus male (holotype). 121. habitus dorsal; 122. habitus lateral; 123. head frontal.

FIGURES 124 – 129. 124 – 126. Mermerizon, male genitalia. 124. M. inbio (holotype); 125. M. mellosus (holotype); 126. M. mesmerizus (holotype). 127. Stipomorpha apicula male (holotype), habitus dorsal. 128 – 129. Stipomorpha crematogastri female (holotype). 128. habitus dorsal; 129. habitus lateral.