Helina rufitibialis Hennig

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 : 258-261

6. Helina rufitibialis Hennig

( Figs 6A–E )

Hebecnema rufitibia Stein ; Becker 1908a: 95 (Tenerife); Frey 1936: 133 (Tenerife, La Gomera); Santos Abréu 1976: 73 ff., fig. 10 (La Palma); Chandler 1979: 106, 120 (La Palma).

Helina rufitibialis Hennig ; Hennig 1958: 218 (Tenerife); Hennig 1978: 5 (Canary Is.); Báez 1983: 185 ff., pl. 1 fig. 7, pl. 2 figs 4, 10 (Tenerife, La Gomera, La Palma).

Hebecnema rufitibia var. luteoligaster Santos Abréu ; Santos Abréu 1976: 75 (La Palma). [Unavailable infrasubspecific name.]

Hebecnema rufitibia var. thoracica Santos Abréu ; Santos Abréu 1976: 76 (La Palma). [Unavailable infrasubspecific name.]

Hebecnema nitidiuscula Santos Abréu ; Santos Abréu 1976: 76 ff. (La Palma).

Material examined. CANARY ISLANDS: [ NHMD]. TENERIFE: Mt Grande, Esperanza, 1400m, 1♁ 28.vii.1989 ( Olsen , Skule & Stadel); Las Portelas , 28°19´N 16°50´W, 830‒860m, 1♀ 16.i.2012, 1♀ 3.ii.2016 ( V. Michelsen). LA GOMERA: El Rincón, 3♁ 20.xi.2002 ( V. Michelsen); El Cedro, 3♁, 3♀ 21.xi.2002 ( V. Michelsen); Los Loros, 28°09´N 17°16´W, 520‒770m, 2♁, 3♀ 31.i‒7.ii.2008, 1♁ 18‒23.i.2012 ( V. Michelsen); Epina, 28°10´N 17°18´W, 600‒670m, 1♁, 1♀ 13‒16.i.2019 ( V. Michelsen); Meriga, 28°09´N 17°14´W, 830m, 1♀ 16.i.2019 ( V. Michelsen); Lomito Fragoso, 28°07´N 17°10´W, 220‒250m, 1♀ 19‒24.i.2019 ( V. Michelsen). LA PALMA: Tigalate, 28°32´N 17°48´W, 680m, 4♁, 1♀ 10‒21.i.2013 ( V. Michelsen) .

Description. Medium sized, wing length 5.3–6.2 mm. Male: Habitus, lateral ( Fig. 6A ). Mainly dark-coloured, with slender legs and abdomen. Antenna and palpus black. Thorax and abdomen dark, rather shiny through thin cover of dark grey to brownish grey pruinosity; usual pattern of four dark stripes on mesonotum visible in posterior view; wing light brownish tinged; both cross-veins strongly shadowed. Abdomen ( Fig. 6B ) with large paired, subtriangular marks on tergites III and IV; no indication of a mid-dorsal dark stripe. Legs black with contrasting yellow tibiae; also basal third or more of hind femur and sometimes basal fifth or more of mid femur yellow. Eyes practically bare. Longest aristal branches one-third as long as width of postpedicel. Frons at narrowest point 0.3–0.8 times as wide as diameter of anterior ocellus and with contiguous fronto-orbital plates. Dorsocentral setae 2 + 3; presutural acrostical field with two rows of setulae slightly standing out from surrounding ground setulae; prealar seta very short, but slightly stronger than ground setulae; katepisternal setae 1 + 2. Scutellum bare at lower lateral margin and ventrally. Vein C without dorsal setulae. Fore tibia without p seta; mid tibia with 1–3 short pd setae; hind femur without pv setae; hind tibia with 3–6 fine av setae on distal half, 1 ad seta and a comb of fine pv setae on middle third. Sternite V and hypopygium as in Figs 6C–E . Female: Apart from usual sexual differences of the head and abdomen differing from the male by the paired marks on tergites III and IV of the abdomen being larger and less well demarcated and by the absence of a pv setal comb on hind tibia.

Distribution. Endemic to Tenerife, La Gomera and La Palma.

Taxonomic note. The male terminalia and thorax chaetotaxy are remarkably similar to those of the Helina clara species-group, but H. rufitibialis is distinctive on account of the short aristal branches and presence of a pv comb of fine setae on hind tibia in the male.

Figures

FIGURE 6. Helina rufitibialis Hennig, male. Habitus (A); abdomen (B); sternite V (C); hypopygium, caudal (D) and lateral (E). Same scale for C–E.