Megatrigon argentifrons, Doczkal & Radenković & Lyneborg & Pape, 2016

Doczkal, Dieter, Radenković, Snežana, Lyneborg, Leif & Pape, Thomas, 2016, Taxonomic revision of the Afrotropical genus Megatrigon Johnson, 1898 (Diptera: Syrphidae), European Journal of Taxonomy 238, pp. 1-36 : 16

publication ID	https://doi.org/ 10.5852/ejt.2016.238
publication LSID	lsid:zoobank.org:pub:36FC5EA6-E82D-4E21-9060-030CF13ED1B7
DOI	https://doi.org/10.5281/zenodo.3854662
persistent identifier	https://treatment.plazi.org/id/CCF520E8-EBFC-4269-956E-C5E31E92DF3F
taxon LSID	lsid:zoobank.org:act:CCF520E8-EBFC-4269-956E-C5E31E92DF3F
treatment provided by	Valdenar
scientific name	Megatrigon argentifrons
status	sp. nov.

Treatment

Megatrigon argentifrons View in CoL sp. nov.

urn:lsid:zoobank.org:act:CCF520E8-EBFC-4269-956E-C5E31E92DF3F

Figs 1B View Fig , 2B View Fig , 3B View Fig , 6 View Fig A–B, 7B, 10B, 11B, 12B, 15

Diagnosis

Frons covered with very dense, long, silvery-white setae and microtrichia; on vertex microtrichia present anteriorly, along lateral sides of ocellar triangle and as small, but distinct postocellar spots ( Fig. 2B View Fig ).

Etymology

The species epithet, which should be treated as a noun in apposition, is derived from the Latin words argentum (= silver) and frons (= forehead), alluding to the dense, silvery microtrichiae that completely cover the frons.

Type material

Holotype

SOUTH AFRICA: ♁, Western Cape, Stellenbosch , 8 Oct. 1926, Dr. H. Brauns leg. ( RMNH).

Paratypes

SOUTH AFRICA: 1 ♁, Western Cape, Uniondale Distr., Bo Kouga, Mar. 1954, museum staff leg. ( SAMC); 1 ♁, KwaZulu-Natal, Bushmans Nek, 2929cc, slopes above hotel, 16 Nov. 1981, J.G.H. Londt leg. ( NMSA).

Description

LENGTH. Body 7.0 mm, wing 5.0 mm.

HEAD ( Figs 2B View Fig , 3B View Fig ). Lateral margins of face more parallel while in M. argenteus comb. nov. slightly divergent; distance between eyes larger than in M. argenteus comb. nov., 0.19 × width of head; ocellar triangle eqilateral, without median longitudinal groove; on face microtrichiose stripes along eye margin wide at the level of antennae, but tapering and reduced at lower part, connected with microtrichia below antenna by tiny oblique microtrichiose line; median facial stripe well developed; microtrichia on postocular orbit do not exceed post-ocular ridge.

THORAX. Mesoscutum with two lateral microtrichiose stripes and two submedian microtrichiose stripes ending well behind level of transverse suture; supra-alar setae yellow; microtrichia on mediotergite medially occupied more than 0.5 of width.

WING. Membrane not infuscated, with light brown veins, microtrichia brown; cell br above vena spuria narrowly bare; costagium with yellow setae.

LEGS ( Fig. 6 View Fig A–B). Setae on legs white without black ones; tarsomere 1 of metatarsus darkened dorsally, but without black setae intermingled with light ones.

ABDOMEN ( Figs 1B View Fig , 7B View Fig ). Tergites 2+3 with large silver spots, touching lateral and posterior margins of tergites, and almost anterior corner; tergite 3 is 2.2 × as wide as long (wider than in the closely related species M. natalensis sp. nov.); distance between silver spots on tergite 3 large, 0.22 × as wide as tergite (larger than in M. natalensis sp. nov.); tergites, especially black parts (median part of tergites 2+3 and whole tergite 4) covered with short, adpressed white-yellow setae (in M. natalensis sp. nov. longer and intensively yellow); silver spots on tergite 3 with reduced setae (contrary to M. natalensis sp. nov.); tergite 4 without microtrichiose spots. Male genitalia in Figs 10B View Fig , 11B View Fig , 12B View Fig .