Helina sexmaculata (Preyssler)

Michelsen, Verner, 2023, Macaronesian Muscidae (Diptera). IV. The genus Helina Robineau-Desvoidy, and description of the male of Spilogona maderensis Michelsen, Zootaxa 5293 (2), pp. 251-276 : 262-264

8. Helina sexmaculata (Preyssler)

( Figs 8A–F )

Spilogaster uliginosa (Fallén) ; Macquart 1839: 115 (Canary Is.).

Mydaea (Spilogaster) uliginosa (Fallén) ; Santos Abréu 1976: 119 ff. (Gran Canaria, Tenerife, La Gomera, La Palma).

Helina uliginosa (Fallén) ; Frey 1945: 103 (Azores); Kirchberg 1967: 334 (Tenerife).

Helina punctata (Robineau-Desvoidy) ; Hennig 1958: 212ff. (Azores, Canary Is.?); Hennig 1978: 5 (Canary Is.?); Báez 1983: 182 ff., pl. 1 fig. 5, pl. 2 figs 2, 8 (Lanzarote, Fuerteventura, Gran Canaria, Tenerife, La Gomera, La Palma).

Mydaea (Spilogaster) uliginosa var. nigripalpis Santo Abréu ; Santos Abréu 1976: 121 ff.(La Palma).[Unavailable infrasubspecific name.]

“ Helina almeriensis (Strobl) ”; Pont 1983: 240 (Canary Is.: La Gomera). Misidentification.

Helina sexmaculata (Preyssler, 1791) ; Pont 1986: 150 (Azores, Canary Is.); Diaz, S. et al. 2005: 78 (Azores).

Material examined. AZORES: [ MZH]. PICO: Madalena , 1♀ 6–9.vii.1938 ( R. Storå) ; SÃO JORGE: Calheta , 1♀ 22–28.vi.1938 ( R. Frey) ; SÃO MIGUEL: Ponta Delgada , 1♀ 14–16.v.1938 ( R. Storå). CANARY ISLANDS: [ NHMD] . GRAN CANARIA: El Valle, 27°54´N 15°32´W, 730‒935m, 1♁, 2♀ 19‒24.i.2017 ( V. Michelsen). TENERIFE: Arico, 1♁ 16.i.2006 ( V. Michelsen). LA GOMERA: Las Carretas, 1♁ 12.i.2006 ( V. Michelsen); Los Loros, 28°09´N 17°16´W, 520‒770m, 2♁ 1‒7.ii.2008 ( V. Michelsen). LA PALMA: Tigalate, 28°32´N 17°48´W, 680m, 4♀ 10‒21.i.2013 ( V. Michelsen); Las Tricias, 28°47´N 17°58´W, 660m, 1♀ 11‒16.i.2013 ( V. Michelsen); Cueva de Agua, 28°48´N 17°57´W, 380m, 1♁, 1♀ 12.i.2013 ( V. Michelsen). MADEIRA: [ MZH]. Camara de Lobos , Estreito , Levada do Norte , 550m, 1♀ 12.xii.1994 (M. Koponen) .

Description. Medium sized, wing length 5.0– 6.4 mm. Male: Habitus, lateral ( Fig. 8A ). Antenna basally and palp brown to ochre yellow (Canary Is) or yellow (Azores, Madeira). Thorax ( Fig. 8B ) black except yellowish on scutellum and frequently even on postpronotal lobes, covered in dense grey pruinosity except for a brownish black pattern of four or six marks on scutum behind the suture and paitred marks laterally on scutellum. Legs yellow with black tarsi; Canary Is. population even with all femora somewhat brownish infuscated. Abdomen ( Fig. 8C ) translucent yellow through thin grey pruinosity and with a brownish black pattern consisting of a narrow median stripe on all tergites, a lateral mark on tergite II and large trapezoid submedian marks on tergites III and IV. Eyes bare. Arista plumose, longest branches c. same length as width of postpedicel. Frons at narrowest point 1–1.5 times as wide as ocellar triangle; frontal vitta at this point slightly narrower to slightly broader than adjacent fronto-orbital plates. Dorsocentral setae 2 + 3; presutural acrostical field with two rows of setulae slightly standing out from surrounding ground setulae; katepisternal setae 2 + 2. Cross-veins r-m and dm-cu narrowly shadowed. Fore tibia with (0–)1 p seta; mid tibia with 2(–3) p setae; hind femur without pv setae; hind tibia with 1(–2) av and 2(–3) ad setae, without pd or p setae. Sternite V and hypopygium as in Figs 8D–F . Female: Apart from usual sexual differences of the head and abdomen differing from the male by the smaller dark marks on mesonotum and abdomen and the frequent presence of a short prealar seta.

Distribution. Azores: Flores, Faial, Pico, Graciosa, São Jorge, São Miguel. Canary Islands: Lanzarote, Fuerteventura, Gran Canaria, Tenerife, La Gomera, La Palma. Madeira (new record). South temperate to subtropical parts of the Holarctic Region and northern Orient.

Taxonomic notes. Pont (1983) showed that the customary concept of Helina sexmaculata (Preyssler) (= uliginosa Fallén , = punctata Robineau-Desvoidy ) included a second, very similar species, H. almeriensis (Strobl) that he found co-occurring with H. sexmaculata in the Mediterranean subregion. Typical individuals of H. almeriensis differs from H. sexmaculata by smaller body size, darker grey body pruinosity, and extensive light to dark brownish colour of antennae, palps and legs, shorter aristal branches, fore tibia in both sexes without a p seta and lobes of the male sternite V more pointed apically. Colour characters alone support the conclusion by Pont (1983) that the Canarian population belong to Helina almeriensis rather than H. sexmaculata : antennal postpedicel brownish black, only extreme base usually orange yellow; palp ochre brown, sometimes darker apically; yellow femora in both sexes with fore femur darkened posteriorly and often even hind femur slightly darkened on distal part. Still, the body size, length of the aristal branches, presence of a submedian p seta on fore tibia in most individuals of both sexes examined have convinced me that H. sexmaculata rather than H. almeriensis represents the “founder” of the slightly melanic Canarian population. The specimens examined from the Azores and Madeira are in all respects typical Helina sexmaculata , which suggests that the populations on these islands represent spreading events from Europe or North Africa that have taken place independently and possibly more recently than the settlement on the Canary Islands.

Figures

FIGURE 8. Helina sexmaculata (Preyssler), male. Habitus (A); head and thorax (B); abdomen (C); sternite V (D); hypopygium, caudal (E) and lateral (F). Same scale for D–F.