Rhagoletis merzi sp. n. (figs 1, c; 7–8)

urn:lsid:zoobank.org:act: ADCCE1F4-7DB8-4EB6-9B5C-339A7F8F6ED9

Rhagoletis batava: Merz, 1994: 108 (misidentification);

Rhagoletis flavigenualis: V. Korneyev in: Merz, 2006: 8 (misidentification);

Rhagoletis sp. near flavigenualis: Korneyev et al., 2018 a: 466.

Type material. Holotype ♂: Switzerland: Visperterminen, VS, 1400 m, 26.07.1990 (Merz) (MNHG ENTO 00012822) (MHNG).

Paratypes: Switzerland: 1 ♀, Visperterminen, h = 1400 m, 17.07.1995 (Merz) (MNHG ENTO 00012824); Visperterminen, VS, 1400 m: 1 ♂, 18.07.1993 (Merz) (MNHG ENTO 0001825); 1 ♂, idem, 1520 m, 20.07.1993 Wald (Merz) (MNHG ENTO 0001828); 1 ♂, idem, 17.07.1995 (Merz) (MNHG ENTO 0001823); 1 ♂, Visperterminen, Kreuz, h = 1500 m, 21.07.2004 (Merz) (MNHG ENTO 0001827) (MHNG); Visperterminen, [Kreuz,] h = 1300–1900 m [swept from Juniperus sabina], 21.07.2004, 1 ♂, 1 ♀ (S. & V. Korneyev) (SIZK).

Non-type specimens. Switzerland: Visperterminen, h = 1300–1900 m, reared from Juniperus sabina fleshy cones, 3 puparia [used for DNA extraction completely], 17.10.2016 (J. Smith).

D i a g n o s i s. Rhagoletis merzi is similar to all other species having the wing pattern with four dark bands, apical band joined to subapical band and separated by a crescent hyaline area from the costal vein anteroapically. It is most similar to, and in fact to our knowledge morphologically indistinguishable from, the Nearctic R. juniperina. Both species have the occiput widely black or brown on the upper 1/3, wing bands uniformly brown to blackish, mid and hind femora black, male lateral surstylus with the posterior lobe relatively short, 0.6–0.75 times as long as surstylus basal of prensisetae (fig. 8, b), and female spermathecae large, 0.09 mm in diameter, with short neck (fig. 2, f). We recognize R. merzi as a distinct species from R. juniperina based on the significant genetic distance between their COI sequences (K2P = 0.071).

Rhagoletis merzi is also very similar to the Central Asian R. mongolica and R. scutellata (both known only from their holotypes, not examined for potential genitalic differences) in general appearance, including the wing pattern and having the occiput widely black on the upper 1/3. Rhagoletis mongolica is also associated with J. sabina, like R. merzi, whereas the host for R. scutellata is unknown. Rhagoletis merzi differs from R. mongolica by having black rather than yellow femora and from R. scutellata by abdominal tergites 2–4 having whitish or yellowish posterior margins and the basicostal cell brownish (in R. scutellata, basicostal cell entirely hyaline and abdominal tergites uniformly black or brown).

This species readily differs from the West Palearctic R. flavigenualis and R. zernyi by having the widely black or brown median occipital sclerite, black mid and hind femora, and uniformly brown wing bands (in R. flavigenualis and R. zernyi median occipital sclerite and all femora uniformly yellow (very rarely only hind femur partly brown), and the wing bands at least partly yellow with brownish borders; R. zernyi differs also by having the discal and subapical bands widely fused). The genetic distance between R. merzi and R. flavigenualis is also significant (K2P = 0.063 –0.066).

Rhagoletis merzi is similar to the Palearctic species R. bagheera and R. batava, and the Nearctic R. bushi in having the wing bands uniformly brown to blackish, and mid and hind femora black, differing from them by having the male lateral surstylus with the posterior lobe conspicuously shorter, 0.6–0.75 times as long as the surstylus basal of the prensisetae (fig. 8, b) vs. 1.3–1.4 times as long as the surstylus basal of the prensisetae in R. bagheera (fig. 3, c) and R. batava (fig. 6, a), and female spermathecae larger, 0.09 mm in diameter, with a short neck (fig. 2, f) vs. 0.02–0.03 mm in diameter, with the neck longer than the spermatheca itself in R. bagheera and R. batava. Rhagoletis merzi also has a different host plant, Juniperus sabina L., vs. Hippophae rhamnoides (Elaeagnaceae) for R. batava and Rhamnus palasii (Rhamnaceae) for R. bagheera. The genetic distance between R. merzi and R. batava is K2P = 0.064 –0.068, and between R. merzi and R. bushi K2P = 0.078 –0.079.

D e s c r i p t i o n. Head. Orange-yellow, ocellar triangle, ventral part of median occipital sclerite and often occiput lateral of it black or brown. Antennal arista pubescent. Setae black except postocellar, posterior genal, and some occipital setae white. Paravertical seta short, about as long as black acuminate postocular setae. — Thorax. Scutum black, yellowish setulose, with microtrichia pattern with two pairs of partly fused matte grayish vittae separated by subshining darker areas.Postpronotal lobe and notopleural stripe creamy white to yellow; scutellum pale yellow, black on anterior margin dorsally and laterally. All thoracic setae black; basal scutellar seta inserted into black area. Halter yellow to creamy white. — Legs. Fore coxa yellow, mid and hind coxae black or brown; fore and mid trochanters yellow; hind trochanter brown or black; fore femur yellow anteroventrally, black posterodorsally; mid and hind femora black except apices yellow; hind femur somewhat thickened in male, with 2–3 longer subapical anterodorsal and 2–3 longer subapical anteroventral setae; tibiae and tarsi yellow (fig. 7). — Wing (fig. 1, c). 2.3 times as long as wide, with pattern consisting of basicostal cell with brownish tinge and four dark brown bands; subbasal band from humeral crossvein over basal half of costal cell through cells br, bm and cua (= anal cell auctt.) slightly into cell cup, discal band from pterostigma over crossvein r-m to posterior margin between veins M 4 (= CuA 1) and CuA + CuP (= CuA 1 +A 1), subapical band from middle of cell r 1 over crossvein dm-m (= dm-cu) and apical band from middle of cell r 1 into apex of cell m 4; discal band separated from both subbasal and subapical bands (figs. 1, c; 7, a) or at most narrowly fused with subapical band at posterior margin (fig. 7, c); subapical and subapical bands fused in cells r 1 and r 2+3; apical band separated from costa between apex of cell r 1 and vein M 1; no intercalary band; vein R 4+5 dorsally with 1 seta at node. — Abdomen. All segments mostly black, posterior margin of tergites 2–4 in male, and 2–5 in female narrowly creamy yellow (figs. 9, b, d). Oviscape shining black, as long as tergite 5; setae and setulae black. — G e n i t a l i a. M a l e. Epandrium black. Proctiger as long as epandrium (fig. 10, b). Surstylus dark yellow, lateral susrtylus with posterior lobe short, 0.6–0.75 times as long as surstylus basal of prensisetae (fig. 9, b). Phallus with moderately large glans (fig. 8, c) having membranous, narrow, finger-like apicodorsal process, large prepuce with smooth walls, and acrophallus with pair of semitubular filaments, very similar to that of R. bagheera (Richter & Kandybina, 1997: fig. 5), R. flavigenualis (fig. 6, c) and R. juniperina (Bush, 1966: fig. 125); preglans short and simple, without eversible caecum. Female. Eversible membrane with two pairs of taeniae 0.5 × as long as membrane itself, ventral side of membrane with scales of different size, medial ones larger than lateral ones and moderately pointed (fig. 9, g). Two globular spermathecae, 0.09 mm in diameter, with long scale-like papillae on surface (fig. 9, f). Aculeus brown, 5.5 × as long as wide, with acute apex (figs. 9, d–e).

Measurements. Body length ♂ = 3.8–4.2 mm; wing length ♂ = 4.1–4.2 mm. Body length ♀ = 4.0– 4.4 mm; wing length ♂ = 3.0, wing length ♀ = 3.6 mm, costal cell length = 0.9; aculeus length = 0.85 mm; aculeus length /costal cell length = 0.9.

Host plant. Juniperus sabina L. The pupae for DNA analysis were reared from the same plants and in the same locality as the type specimens were swept.

Distribution. Switzerland.

Etymology. This species is named in honor of the eminent Swiss dipterist Dr.Bernhard Merz, who collected most of the type specimens, in recognition of his contributions to the study of fruit flies.

Remarks. Kandybina (1977) reported specimens of “ R. mongolica ” with entirely black femora and partly black tibiae reared from Juniperus sabina in Kyrgyzstan, which need re-examination to determine whether they are conspecific with R. merzi.