Peradon diaphanus (Sack)

Reemer, Menno, Skevington, Jeffrey H. & Kelso, Scott, 2019, Revision of the Neotropical hoverfly genus Peradon Reemer (Diptera, Syrphidae, Microdontinae), ZooKeys 896, pp. 1-93 : 1

Peradon diaphanus (Sack) Figs 32 , 109 , 186

Microdon diaphanus Sack, 1921: 146. Holotype ♂: Paraguay, St. Trinidad (lost); Thompson et al. 1976: 64.

Peradon diaphanus (Sack): Reemer and Ståhls 2013a: 146.

Studied type specimens.

Paraguay • 1 ♀, neotype of Microdon diaphanus Sack (new designation, see notes); Encarnacion; 15 Jun. 1927; Shannon & Del Ponte leg.; USNM.

Label 1: "ex ant colony / in arboreal / bromelia"; label 2: "Encarnacion / Paraguay 15.6.27 / Shannon & Del Ponte ””; label 3: "USNMENT / [barcode] / 01371103". Coll USNM. With empty puparium mounted on same pin.

Additional specimens.

Brazil • 1 ♀; Jundiahy; 13 Aug. 1899; NHMUK.

Paraguay • 2 ♀; same label data as neotype; USNM.

Diagnosis.

Body length: male 16 mm (based on Sack 1921), female 16.5-18.5. The constricted abdomen, absence of a triangle of golden pile on the mesoscutum, and partly dark wings place P. diaphanus in a group with P. elongatus , P. hermetia and P. hermetoides . Peradon diaphanus differs from the other three species by tergite 2 being longer than wide, and also by the rufous golden pilose mesoscutum.

Notes.

According to Pape and Thompson (2013), Reemer and Ståhls (2013a) and Thompson et al. (1976), the type of Microdon diaphanus is deposited in the DEI ( Müncheberg). However, attempts to find it in that collection failed (pers. comm. F. Menzel). The DEI is part of the Senckenberg research institute, which also holds entomological collections in Dresden (SNSD) and Frankfurt (SMF). Enquiries at these institutions did not result in finding the type either. As a large part of the collection of P. Sack was destroyed during World War II ( Franz 1967), it seems probable that this has also happened to the type of M. diaphanus . In order to ensure the stability of this taxon, a neotype designation is deemed desirable. One female from Brazil (coll. NHMUK) and three females from Paraguay (coll. USNM) agree well with the original description and the figure in Sack (1921). As the species was originally described from Paraguay, one of the Paraguayan females is here designated as neotype.

The three females from Paraguay are mounted together with empty puparia and carry labels stating "ex ant colony in arboreal bromelia". This is the first known record of an association of a Peradon species with ants. Unfortunately, the ants remain unidentified.

Distribution.

Known from the Brazilian state São Paulo and from Paraguay.

Figures

Figures 32 - 35. Tergite 2 dorsal 32 Peradon diaphanus female (neotype) 33 P. elongatus male (Brazil INPA) 34 P. hermetia male (holotype) 35 P. hermetoides male (holotype).

Figures 105 - 111. Dorsal habitus of Peradon species (trivittatus group) 105 P. hermetia ♂ holotype 106 ♂ P. hermetoides holotype 107 P. elongatus ♂ Brazil INPA 108 P. elongatus ♀ Brazil INPA 109 P. diaphanus ♀ neotype 110 P. oligonax ♂ Brazil LACM 111 P. oligonax ♀ Peru RMNH. Scale bar: 10 mm.

Figures 186 - 193. 186 Peradon diaphanus female, neotype: habitus lateral 187 - 190 Peradon elongatus male, holotype: 187 habitus dorsal 188 habitus lateral 189 head frontal 190 head lateral 191 - 193 Peradon elongatus female, paratype: 191 habitus dorsal 192 head frontal 193 head lateral.