(Figs. 1–9)

Type material. Holotype (female): Iran: Charmahal & Bakhtiari Province, south part of Choghakhor Lake, 2600m, 31°53' N, 50°58' E, swept from flower heads of Cousinia archibaldii, 08.vi.2013, Mohamadzade (JAZM). Paratypes: Iran: 20♂, 17♀, same collection data as holotype; 7♂, 6♀, Charmahal & Bakhtiari Province, south part of Choghakhor Lake, 2600m, 31°52' N, 50°57' E, swept from flower heads of Cousinia archibaldii, 28.v.2014, Mohamadzade (JAZM, MHNG, SIZK, ZISP and SMNC); Fars Province, Mah Parviz pass, 60 km to Yasuj, 2600m, 31°52' N, 50°57' E, 26.v.2014, V. Korneyev (SMNC). Armenia: 1♀, Vedi, 25.vi.1981, Ermolenko (SIZK).

Diagnosis. U. bakhtiari is similar to U. iani and U. xanthippe in having smaller body size and shorter wings (♀WL <4mm), strongly reduced wing pattern and yellow femora. It differs only by the shape of the aculeus tip, which has two pairs of distinct preapical steps (U. xanthippe has one pair of distinct steps; U. iani has distinct proximal steps and indistinct distal steps), and also has a different host plant.

Description. Head. Length: height: width ratio = 1: 1.15: 1.42. First flagellomere 1.6 times as long as wide (Fig. 3). Compound eye 1.15 times as high as long. Gena as high as length of first flagellomere. Wing Entirely hyaline, without crossbands. Distal part of costal vein black. Pterostigma yellowish. Distance between crossveins as long as dm-cu crossvein (Fig. 1). Legs completely yellow (Fig. 1). Terminalia. Aculeus tip with 2 pairs of distinct preapical steps; distance between their apices at the level of proximal steps greater than that from their level to aculeus apex and also with notch at apex, as in Figs. 4 & 5. Epandrium and glans as in Figs. 6–8, very similar to those in Urophora cardui (Linnaeus 1758) (see Freidberg & Norrbom 1999: fig. 23.7 L) and U. stylata (Fabricius 1775) (see Freidberg & Kugler 1989: Fig. 48).

Measurements. Holotype ♀: BL = 6.25, WL = 3.6; ♂: BL = 2.9–4.25mm (average 3.7), WL = 2.6–3.6 mm (average 3.3); ♀: BL = 5.5–6.5mm (average 6.2) WL = 3.5–4.2mm (average 3.7) (n = 10), AL = 3.1–3.3 mm (average 3.2), AL/WL = 0.75–0.83 (average 0.79) (n = 5).

Etymology. This species is named after the Bakhtiari tribe (a southwestern Lurish tribe) that live in the type locality of the new species.

Host plant. Cousinia archibaldii Rech., from which adults were collected, is probably a host for this species, but this needs to be confirmed by rearing.