Fannia caucasica, Pont, Adrian C., 2015

Pont, Adrian C., 2015, Description of a new species of Fannia Robineau-Desvoidy, 1830 (Diptera: Fanniidae) and distribution records of the genus from the Caucasus Mountains, Zootaxa 3956 (1), pp. 140-148 : 141-143

Fannia caucasica sp. nov.

( Figs. 1–5 )

Holotype. Male. GEORGIA: Mtskheta-Mtianeti: Caucasus Mts, Kazbegi area, Dzhuta, river, 2200 m, 12.vii.1983 (A.C. Pont), in BMNH.

Paratypes, 19♂. GEORGIA: data as for holotype, 11♂ (9 BMNH, 2 OUMNH). ARMENIA: Gegharkunik: River Gavaraget at Sarukhan, N40.20 E45.07, 1960 m, 6.vi.2005 (A.C. Pont), 3♂ ( BMNH); between Sarukhan and Lanjaghbyur, N40.19 E45.07, 1960 m, 6.vi.2005 (A.C. Pont), 1♂ ( BMNH). Vayots Dzor: River Arpa at Jermuk Town, N39.50 E45.41, 1970 m, 11.vi.2005 (A.C. Pont), 4♂ (3 BMNH, 1 OUMNH).

Additional material examined: ARMENIA: Aragatsotn: 1 km S of Sipan, N40.43 E44.16, 2100 m, 18.vi.2010 (A.C. Pont), 1♀ ( BMNH). [This female is doubtfully determined, see Comments below]

Description. This species belongs to the Fannia serena -subgroup ( Chillcott, 1961; Rozkošný et al., 1997) and is one of the species in which the male cercal plate is shaped like an inverted letter “T”. Because of the close similarity of these species, a full description is not needed. Only the differential characters and a few additional characters of the new species are given, and its differences from the other species are listed (see Comments below).

Male. Length of body, 4.0– 4.5 mm. Length of wing, 3.5–4.0 mm. A small, very dark species ( Fig. 1 ). Frons at narrowest point as wide as width of postpedicel. 6–7 pairs of well-spaced frontal setae. Post-ocular setulae with a second row almost from vertex. Prementum thinly dusted. Scutum black, matt when viewed from behind but without any dusted pattern, postpronotal lobe light grey dusted. Acrostichal setulae biserial throughout. 2 prealar setulae. Legs black, including knees. Fore tibia without submedian setae. Mid femur with a full row of posteroventral setae, these long in basal half where a few are much longer than depth of femur. Mid tibia with 1 anterodorsal and 1 posterodorsal seta. Mid basitarsus without a basal ventral thorn. Hind femur with a complete row of anteroventral setae, finer and shorter in basal half where they are as long as femoral depth, and a row of posteroventral setae in basal half that are almost as long as femoral depth. Hind tibia with a submedian and preapical dorsal seta, 1 anterodorsal and 1 anteroventral. Wings dark smoky. Upper calypter creamy, with a yellow margin; lower calypter linear. Knob of haltere black. Abdomen wholly black, grey dusted in posterior view and with the usual black subtriangular pattern on syntergite 1+2 and tergites 3 and 4 ( Fig. 2 ), tergite 5 black but with a narrow line of dust along fore-margin that is interrupted medially.

Female. Not known for certain. See below.

Distribution. Known from Armenia and Georgia, from localities between 1600 and 2200 m.

Etymology. The species name is formed from the name of the Caucasus Mountains.

Comments. The species that F. caucasica sp. nov. resembles most closely by having males with a cercal plate shaped like an inverted letter “T” differ from F. c a uc a s i c a sp. nov. as follows. Externally F. caucasica is most like F. subsimilis Ringdahl whilst the male terminalia are most like those of F. similis (Stein) .

Fannia serena (Fallén, 1825) : post-ocular setulae in a single row; hind femur without ventral setae except for 2 anteroventrals in apical third; knob of haltere yellow; tergite 5 grey dusted with a narrow black median line; surstylus without the pronounced swelling on posterior margin.

Fannia similis (Stein, 1895) : post-ocular setulae in a single row; scutum extensively grey dusted; 1 prealar setula; fore knees yellow; hind femur with the anteroventral setae very short in basal half, without posteroventrals; knob of haltere yellow; abdomen very extensively light grey, almost bluish, dusted, including tergite 5 which has only a faintly indicated and incompletely dark median vitta; surstylus very similar in shape to that of F. caucasica sp. nov.; cercal plate not as expanded at apex; lobe at lower posterior corner of epandrium shorter.

Fannia subsimilis Ringdahl, 1934 : post-ocular setulae in 2 rows; scutum black, matt; hind femur with the anteroventrals very short in basal half, without posteroventrals; knob of haltere brown; abdomen very extensively grey dusted, the median black marks hardly expanded posteriorly, tergite 5 grey except for a black median line; surstylus with a much smoother outline; lobe at lower posterior corner of epandrium very short.

Fannia carbonella (Stein, 1895) : 9–10 frontal setae; post-ocular setulae in one row; hind femur with posteroventral setae in apical half but without any in basal half; upper calypter smoky, the margin brown; abdomen light grey, almost bluish, dusted, tergite 5 dusted and with a narrow black median vitta.

In Rozkošný et al. (1997), which includes all the West Palaearctic species of the serena -group, the male of F. caucasica sp. nov. runs to couplet 63 which can be modified as follows:

63. Hind femur with some posteroventral setae equalling greatest width of femur, either in basal half (F. c a u c a s i c a) or in apical

half ( F. alpina , F. carbonella ).......................................................................... 64 - Hind femur without elongate posteroventral setae.......................................................... 65 64. Presutural acrostichal setulae triserial; cercal plate tapered in apical part.......................... F. alpina Pont, 1970 - Presutural acrostichal setulae biserial; cercal plate expanded in apical part in the shape of an inverted letter “T”....... 64a 64a. Hind femur with several posteroventral setae, confined to basal half; post-ocular setulae biserial; in posterior view, tergite 5

almost wholly shining black, with a little grey dust along fore-margin........................... F. caucasica sp. nov. - Hind femur with a few posteroventral setae, confined to apical third; post-ocular setulae uniserial; in posterior view, tergite 5

densely grey dusted except for a narrow black median line................................ F. carbonella (Stein, 1895)

What may be the female of this species will key in Rozkošný et al. (1997) to couplet 42, which can be modified as follows:

42. Fore tibia yellowish at base. Post-ocular setulae uniserial..................................... F. parva (Stein, 1895) - Fore tibia wholly black. Post-ocular setulae mainly biserial................................................. 42a 42a. Fronto-orbital plate with the pruinosity usually tinged with brown, especially above and inside. Hind femur with 3 strong

anteroventral setae before apex..................................................... F. carbonella (Stein, 1895) - Fronto-orbital plate wholly grey pruinose. Hind femur with 2 strong anteroventral setae before apex, preceded by a row of

strong setulae along the whole length of the femur..........................................? F. caucasica sp. nov.

Figures

FIGURES 1 – 2. Fannia caucasica sp. nov. (♂ holotype). 1. Male in lateral view. 2. Male abdomen in posterior view.

FIGURES 3 – 5. Male terminalia of Fannia caucasica sp. nov. (♂ paratype from Armenia, River Gavaragat at Sarukhan). 3. Hypopygium in posterior view. 4. Hypopygium in lateral view. 5. Sternite 5. Scale-line 0.25 mm.