Chamaepsila ristolasiensis, Claude & Tissot, 2023

Claude, Jocelyn & Tissot, Bruno, 2023, Additional data on the fauna of Psilidae (Diptera) of France, with description of three new species of Chamaepsila and updated keys, Zootaxa 5380 (2), pp. 101-133 : 108-110

Chamaepsila ristolasiensis sp. nov.

urn:lsid:zoobank.org:act:CA9D2F8D-DD00-496D-B92F-4B529F24EB94

( Figs. 10–15 )

Examined material (9♂ & 3♀). HOLOTYPE: male ( Fig. 10–12 ), FRANCE, Hautes-Alpes , RNRM, Abriès-Ristolas, Malaise trap n°55 ( Fig. 13 ), 44.7045625°N 7.0412671°E, 2340 m asl, 11.viii.2016, rec and leg. Alain Bloc & Anne-Laure Bonato, coll. MHNG pinned and terminalia preserved in microvial in glycerine . PARATYPES: same data as holotype but: Malaise trap n°55, 1♂, 11.viii.2016 and 1♀, 27.vii.2016, preserved in ethanol 70%, coll. JC; Malaise trap n°55, 1♀, 27/07/2016, 1♂, 28.vi.2016, 1♂, 27.vii.2016 and 1♂, 11.viii.2016, Malaise trap n°56, 44,7042322°N 7,0431520°E, 2400 m asl, 2♂, 10.viii.2016, 2♂, 05.ix.2017, Malaise trap n°73, 44,7046309°N 7,0386541°E, 2160 m asl, 1♀, 18.vii.2017, pinned, coll. MHNG; Malaise trap n°73, 1♂, 18.vii.2017, preserved in ethanol 70%, coll. BT .

Description. MALE. Body length: 6–7 mm. Head. Ground colour yellow. Ocellar triangle brown to black. Antenna yellow, including postpedicel, which is twice as as long as wide at base. Arista brown, conspicuously thickened at the base, covered with yellow fine rays. Pilosity almost as long as the diameter of the arista at its widest point. The eye is ovoid, as high as it is wide, and as high as the gena. Frons and fronto-orbital plates are uniformly brownish. Lunula brown. Face yellow. Palpi yellow with black apex. Prelabrum black to brown. Occiput yellowish. Chaetotaxy (all setae black): (2) 3 vertical setae; 1 postocellar seta; 2 fronto-orbital setae (sometimes 3). Thorax. Ground colour yellow with four black stripes on scutum, one pair on each side of the transverse suture, but the stripes may sometimes consist of small spots. Scutellum yellow. Postnotum yellow. Notopleural line darkened. Pleura entirely yellow, except for a brown spot on the anepimeron, which is bare. Postpronotal lobes yellow. Chaetotaxy (all setae black): 1 notopleural seta; 1 supra-alar seta; 1 post-alar seta; 1 dorsocentral setae; 1 pair of apical scutellar setae. Abdomen. Brown with yellow pilosity. Legs: Yellow, with yellow to brown pilosity. Tarsi dark. Wing: Length: 5 mm, infuscate along the veins. Veins yellow in the basal half, brown in apical half. Halter white, yellowish at the apex. Genitalia ( Figs. 14–15 ). Male terminalia measurement: 0.7 mm lenght in ventral view. Postgonites are angular and crudely serrated. The phallus is triangular and pointing downwards. The base of the phallopodeme lies at the edge of the epandrium (including postgonites arms), unlike most other European Chamaepsila .

FEMALE. Same as the male for morphological aspects. Terminalia not studied.

Etymology. The new species is named after its origin: the National Nature Reserve of the Ristolas-Mont Viso in the Alps. Specific epithet in genitive case.

Ecology. Adult habitat. Subalpine heath (Rhododendro ferruginei-Vaccinion myrtillin, Salicion lapponiglaucosericea, Loiseleurio procumbentis -Vaccinion microphylli and Juniperion nanae - Tissot et al. 2018). Altitude. 2160 to 2400 m asl. Phenology. June to September. Larval habitat. Unknown.

Currently known distribution. France (Provence-Alpes-Côte d’Azur: Hautes-Alpes).

Differential diagnosis. Male. C. ristolasiensis is very similar to C. withersi sp. nov. Both species have smoked the wings infuscate along the veins ( Figs. 3–12 ), which distinguishes them from all other species of the genus, except C. obscuritarsis . C. ristolasiensis further resembles C. withersi in the following characteristics: Pleura yellow with a black spot on the anepimeron, notopleural line darkened, size of the terminalia and atriangular and downward pointing phallus. It can be distinguished from C. withersi by the following characters: Postnotum without dark spot, legs yellow with dark tarsi (yellow tarsi in C. withersi ) and terminalia ( Fig. 14 ). The base of the phallopodeme lies at the edge of the epandrium (including the postgonite arm) whereas it descends from the postgonite in C. withersi (compare Figs. 5 and 14 ). The postgonites of the two species are also different, even when viewed from the front: angular and serrated in C. ristolasiensis versus triangular with rounded corners in C. withersi . In lateral view the epandrium of C. ristolasiensis , is slimmer than that of C. withersi (compare Figs. 6 and 15 ). C. ristolasiensis is also close (colour, size and habitus) to C. obscuritarsis , but differs in having a single pair of scutellar setae. In case of doubt, the male terminalia should be compared with those of C. obscuritarsis ( Figs. 22–23 ). Female. Same as male. Terminalia not studied.

Figures

FIGURE 13. Near the Malaise trap n°55 in France, Ristolas-Mont Viso (Hautes-Alpes), where the holotype and paratypes of Chamaepsila ristolasiensis sp. nov. were captured (Photo: Alain Bloc)

FIGURES 10–12. Habitus of the male of Chamaepsila ristolasiensis sp. nov., holotype, before pinning. 10: dorsal view. 11: lateral view. 12: wing details. Scales bars = 0.5 mm. (Photo: Jocelyn Claude)

FIGURES 14–15. Male terminalia of Chamaepsila ristolasiensis sp. nov. 14: in ventral view. Scale bar = 0.3 mm. 15: left epandrium in lateral view. Scales bars = 0.1 mm. (Drawings: Jocelyn Claude)

FIGURES 1–3. Habitus of the male of Chamaepsila withersi sp. nov., holotype, before pinning. 1: dorsal view. 2: lateral view. 3: wing details. Scales bars = 0.5 mm. (Photo: Jocelyn Claude)

FIGURE 4. Malaise trap n°117 in France, Natural Reserve of hauts de Chartreuse (Isère), where the holotype of Chamaepsila withersi sp. nov. was captured (Photo: Jocelyn Claude)

FIGURES 5–6. Male terminalia of Chamaepsila withersi sp. nov. paratype. 5: in ventral view. 6: left epandrium in lateral view. Scales bars = 0.1 mm. (Drawings: Jocelyn Claude)

FIGURES 7–9. Habitus and habitat of Chamaepsila withersi sp. nov. in France in Hautes-Alpes (near Col de l’Izoard). 7: Male paratype in natura on Cirsium spinosissimum (L.) Scop., 1769. Scale bar = 1 mm. 8: Gypsum dissolution funnel. The arrow shows the capture site. 9: Mats of C. spinosissimum growing at the bottom of the depression where holotypes were collected. (Photo: Christophe Lauriaut)

FIGURES 22–23. Male terminalia of Chamaepsila obscuritarsis (Loew, 1856). 22: in ventral view. 23: left epandrium in lateral view. Scales bars = 0.1 mm. (Drawings: Jocelyn Claude)