Limnophora obsignatula, Michelsen, 2021

Michelsen, Verner, 2021, Macaronesian Muscidae (Diptera). II. The genus Limnophora Robineau-Desvoidy with description of a new Canarian endemic species, Zootaxa 4952 (1), pp. 101-127 : 111-113

Limnophora obsignatula sp. nov.

( Figs 5A‒C , 6A‒C , 8D‒F , 12C )

“ Spilogaster notata (Fallén) ”; Macquart 1839: 115 (Canary Is.). Misidentification.

“ Limnophora obsignata (Rondani) ”; Becker 1908a: 102 (Tenerife); Frey 1936: 132 p.p. (Gran Canaria, Tenerife, La Gomera, La Palma); Hennig 1959: 376 (Canary Is. only); Chandler 1979: 120 (La Palma); Santos Abréu 1976: 94 (La Palma); Báez 1981: 628 p. p. (La Gomera?, La Palma). Misidentifications.

“ Limnophora notata (Fallén) ”; Santos Abréu 1976: 96 (La Palma). Misidentification.

The Canarian records listed above may for the most part represent misidentifications of Limnophora obsignatula sp. nov., an endemic Canarian species replacing the very similar and widespread L. obsignata (see above) in the western islands of Gran Canaria, Tenerife, La Gomera and La Palma. However, the material recorded by Frey (1936) on the authority of the muscid specialist J. Villeneuve even contains specimens of L. quaterna (see below), and the records of L. obsignata by Báez (1981) from La Palma, La Gomera and Fuerteventura refer in part or entirely to L. paneliusi (see below) as evidenced by his illustrations of the male body pattern (pl. I, figs 4‒5) and genitalia (pl. II, figs 1, 3).

Material examined. CANARY ISLANDS: Type material [ NHMD]: Holotype ♂, TENERIFE: Carrizal Alto, 28°19´N 16°51´W, 640‒730m, 30.i‒3.ii.2016 ( V. Michelsen). Paratypes: LA PALMA: Bco. Gallegos, 28°48´N 17°49´W, 470m, 1♂ 17.i.2013 ( V. Michelsen). LA GOMERA: La Laja, 28°06´N 17°11´W, 480‒600m, 7♂, 2♀ 23.xi.2002, 4♂, 2♀ 22‒29.i.2016 ( V. Michelsen); Los Loros, 28°09´N 17°16´W, 520‒770m, 6♀ 1‒7.ii.2008 ( V. Michelsen); Bco. Arure, 28°06´N 17°19´W, 200‒265m, 3♀ 4.ii.2008 ( V. Michelsen); Bco de Aguajilva, Lomito Fragoso, 28°07´N 17°10´W, 220‒250m, 6♂, 6♀ 19‒24.i.2019 ( V. Michelsen). TENERIFE: Los Carrizales, 28°19´N 16°51´W, c. 645m, 3♂, 2♀ 8‒10.ii.2008 ( V. Michelsen); Carrizal Alto, 28°19´N 16°51´W, 640‒730m, ♀ 30.i‒ 3.ii.2016 ( V. Michelsen). Other material [ MZH, NHMD]: GRAN CANARIA: Los Lagunetas, 3♂, 2♀ 1931 ( R. Storå); Moya, 2♂ 1931 ( R. Storå). TENERIFE: Agua Garcia, 1♀ 1931 ( R. Frey); Las Mercedes, 1♀ 1931 ( R. Storå); Valle de Masca , 1♂, 2♀ 12‒13.v.1947 (H. Lindberg). LA GOMERA: Cumbre, 5♂, 6♀ 1931 ( R. Frey); Hermigua, 2♂, 5♀ 1931 ( R. Frey, R. Storå); Bco de Aguajilva , Lomito Fragoso, 28°07´N 17°10´W, 220‒250m, 3♀ 24‒29.i.2020 ( V. Michelsen). LA PALMA: La Caldera, 2♂ 1931 ( R. Storå), 1♂, 1♀ 7.viii.1931 ( R. Frey) ; Santa Cruz, 1♂ 1931 ( R. Frey) .

Sixteen specimens (8♂, 8♀) from totally 123 specimens examined showed fungal infection by Stigmatomyces sp., presumably S. limnophorae Thaxt. (Laboulbeniales) .

Etymology. The specific epithet hints at its probable status as sister species of L. obsignata .

Description. Medium sized, wing length 3.9‒5.8mm. Male. Arista ( Fig. 6B ) short-plumose, longest branches ca. 0.75 times as long as width of postpedicel. Head and body ( Figs 5A, B ) black, covered in dense, mainly whitish grey pruinosity with a contrasting black “ Anthomyia -pattern” on dorsum of thorax and abdomen. Head ( Fig. 6A ) more or less brownish pruinose on frons, parafacialia and face; brownish black on upper half of occiput. Frons at narrowest point 0.9‒1.2 times as wide as ocellar tubercle, frontal vitta at this point 1.6‒2.0 times as wide as the fronto-orbital plates; fronto-orbital plate with 1‒2 short reclinate orbital setae immediately above 5‒7 inclinate frontal setae. Frons lying slightly behind moderately produced facial margin. Mesonotal black pattern with pair of large, squarish presutural marks with narrow, wedge-shaped separation disappearing on occipital declivity; band immediately behind the suture very broad, its hind margin almost straight, lying distinctly behind the insertion of third pair of postsutural dorsocentral setae; a narrow median stripe from the postsutural band sometimes extends to the black band on basal two-thirds of scutellum. Dorsocentral setae 4 behind the suture; presutural acrostichal field with setulae only, arranged in four rows separated from adjacent dorsocentral setae by a bare stripe. Calypteres brownish infuscated at the margins; wing membrane faintly brownish black tinged; halter pale yellow; vein M 1 distinctly curved forward in distal part. Mid femur with 2 subapical pd setae and 3‒4 pv setae on basal third; mid tibia with 2(‒3) p setae inserted above and one below middle. Hind femur with 2(‒3) av setae distally, without pv setae. Abdomen ( Fig. 5C ) with paired blackish marks on tergites I‒II, III and IV and a median brown mark on tergite V; marks on tergites III and IV large, trapezoid, as long as respective tergites and laterally extended approximately to dorsally visible margin of the abdomen. Sternite I bare. Sternite V and hypopygium as in Figs 8D‒F ; distinguished from male L. obsignata by the shape of the surstyli. Female. Head ( Fig. 6C ) on upper two-thirds of frons with a band of brown pruinosity contrasting with light grey vertex and silvery grey lower fronto-orbital and parafacial plates. Fronto-orbital plate with 2 reclinate orbital setae and 5 inclinate frontal setae. Mesonotum with separation between presutural black marks broader, wedge-shaped, posteriorly as wide as acrostichal field. Calypteres paler, dirty whitish. Mid femur basally with 1 pv seta only. Abdomen with paired black marks on tergites III and IV large, trapezoid. Ovipositor is in Fig. 12C , inseparable from that of L. obsignata . See Table 1 for ovipositor characters.

Distribution. Apparently endemic to the western Canary Islands. Known so far from Gran Canaria, Tenerife, La Gomera and La Palma.

Figures

FIGURE 5. Limnophora obsignatula sp. nov. (A‒C). Male, lateral (A) and dorsal (B); male abdomen, dorso-lateral (C). Different scales for A, B and C.

FIGURE 6. Limnophora obsignatula sp. nov. (A‒C), L. paneliusi Emden (D‒F). Male head, dorso-lateral (A, D); male postpedicel and arista (B, E); female head, sub-dorsal (C, F). Different scales for A, C, D, F and B, E.

FIGURE 8. Limnophora obsignata (Rondani) (A‒C), L. obsignatula sp. nov. (D‒F). Males. Sternite V (A, D), hypopygium caudal (B, E) and lateral (C, F). Same scale.

FIGURE 12. Limnophora exigua (Wiedemann) (A, B), L. obsignatula sp. nov. (C), L. riparia (Fallén) (D). Ovipositor, lateral (A, C, D) and dorsal (B). Same scale.