Helina santosabreui, Michelsen, 2023

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 : 267

10. Helina santosabreui sp. n.

( Figs 9E, F )

Mydaea (Spilogaster) duplicata var. tagojana Santos Abréu ; Santos Abréu 1976: 115 ff., fig. 17 (La Palma). [Unavailable infrasubspecific name.]

“ Helina quadrum (Fabricius) ”; Báez 1983: 183 ff., pl. 1 fig. 6, pl. 2 figs 1, 7 (La Gomera, La Palma). Misidentification.

Material examined. CANARY ISLANDS: Type material (holotype ♁, paratypes 5♀) [ NHMD]: LA GOMERA: El Rincón, 1♀ 20.xi.2002 ( V. Michelsen); Los Loros , 28°09´N 17°16´W, 500‒770m, 1♀ 1.ii.2008 ( V. Michelsen); LA PALMA: Tigalate, 28°32´N 17°48´W, 680m, 2♀ 10‒21.i.2013 ( V. Michelsen); Las Tricias, 28°47´N 17°58´W, 660m, holotype ♁, 2♀ 11‒16.i.2013 ( V. Michelsen). Other material [ MZH]. LA PALMA: supra El Paso, 600m, 1♀ 4.iv.1950 (H. Lindberg) .

Description. Medium sized, wing length 6.0–7.0mm (n = 8). Male: Head and body mainly dark, densely greyish pruinose, in posterior view with four brownish-black stripes on anterior two-thirds of scutum (interrupted at the suture); abdomen ( Fig. 9E ) broad-ovoid with paired blackish marks on tergites III and IV in shape of large, almost full-length rectangles; linear brown marks further present in the middle of tergites III–V; cross-veins, or at least r-m, faintly shadowed. Legs dark with ochre-brown mid- and hind tibiae. Eyes bare. Arista plumose, longest branches about same length as width of postpedicel. Frons at narrowest point narrower than ocellar tubercle; fronto-orbital plates at this point narrowly separated by frontal vitta. Dorsocentral setae 2 + 4; presutural acrostical field with setulae only arranged in 4–5 irregular rows; prealar seta very short; katepisternal setae 2 + 2. Fore tibia with 1 p seta; mid tibia with 0 ad and 2–3 p setae; hind femur without pv setae; hind tibia with 2–3 av, 3 ad setae, 1 short pd seta in upper third and in middle third with inconspicuous comb of fine p setae. Terminalia: not examined in the absence of available males other than the holotype, but see Báez (1983, pl. 2, figs 1, 7, as “ H. quadrum ”), showing the cerci forming a cordiform plate as also seen in H. reversio . Female: apart from usual sexual differences of the head and abdomen different from the male by the abdomen ( Fig. 9F ) having rectangular dark marks on tergites III–IV not quite reaching hind margin of tergites, legs ochre yellow even on fore tibia and tips of mid- and hind femora and hind tibia without row of fine p setae.

Distribution. Endemic to the western Canary Islands. Known so far from La Gomera and La Palma.

Taxonomic notes. Helina santosabreui seems closely related to the common, widely distributed H. reversio with which it co-exists on La Gomera and La Palma. It differs in both sexes by the slightly stouter body outline, by the paired dark marks on tergites III and IV being larger, rectangular, and by the presence of a p seta on fore tibia.

Figures

FIGURE 9. Helina reversio (Harris) (A–D), H. santosabreui sp. nov. (E, F). Abdomen, male (A, E) and female (F); sternite V (B); hypopygium, caudal (C) and lateral (D). Same scale for B–D.