Key to Iranian species of Coenosia Meigen, 1826

The following key is primarily based on the key by Gregor et al. (2016) and includes all seven species known from Iran including the newly described C. persica Pont & Parchami-Araghi, sp. nov.

1 Hind tibia with a median anterodorsal and a true anterior seta, placed close to each other............................ 2

- Hind tibia with a median anterodorsal and anteroventral setae that are not close to each other......................... 5

2 Body shining black (Fig. 20); male cercal plate subelliptical (Fig. 27); male sternite 5 horseshoe-like (Fig. 26).............................................................................................. C. atra Meigen, 1830

- Body not shining, weakly dusted; male sternite 5 not as above................................................. 3

3 Parafacial at least as wide as width of postpedicel; length of longest aristal hairs equal to or longer than width of postpedicel (Fig. 25); male cercus and surstylus elongate (Figs 42–43); male sternite 5 V-shaped (Fig. 41)...................................................................................................... C. tigrina (Fabricius, 1775)

- Parafacial visibly narrower than width of postpedicel; longest aristal hairs at most as long as postpedicel; male terminalia and sternite 5 not as above................................................................................. 4

4 Aristal hairs longer than greatest diameter of arista; abdominal tergites 3–4 with paired round spots and a narrow median stripe; femora, antenna and palpus black in both sexes (Fig. 22); male cercal plate forked apically (Fig. 33); male surstylus blunt, setose on inner side (Fig. 34); male sternite 5 broadened basally (Fig. 32).................... C. humilis Meigen, 1826

- Arista short pubescent; abdominal tergites without spots; male femora, antenna and palpus yellow (Fig. 21); male cercal plate apically truncated and spinose (Fig. 30); surstylus sword-shaped, as long as cercus (Fig. 31); male sternite 5 basally broad (Fig. 29); female with femora, antenna and palpus black............................... C. attenuata Stein in Becker, 1903

5 Two proepisternal setae; abdominal tergites entirely dark; fore femur entirely dark, mid and hind femora yellow in apical half; palpus and abdominal tergites dark (Figs 12–13); male cercal plate elongate, tapered, without apical spines; male surstylus shorter than cercus (Figs 15–16, 18–19); male sternite 5 basally narrowed, almost V-shaped (Figs 14, 17)............................................................................... C. persica Pont & Parchami-Araghi, sp. nov.

- Only 1 proepisternal seta; abdominal tergites partly yellow (Figs 23–24); male cercal plate oval (Figs 36, 39), moderately curved anteriorly (Figs 37, 40); other characters not as above.................................................. 6

6 Mid femur usually with 2 posterior setae, and in basal half with 3–4 strong posteroventral setae; frontal vitta wholly black; male with hairs on outer (posterior) surface of fore tarsomeres conspicuous, at least as long as depth of tarsomeres; hind femur with a complete row of anteroventral setae and with several posteroventral setae on a little over basal half (Fig. 24); male surstylus thumb-shaped; distiphallus bent right angularly (Fig. 37); sternite 5 (Fig. 35).............. C. nigridigita Rondani, 1866

- Mid femur with 1 posterior preapical seta, and in basal half with only 1–2 posteroventral setae; frontal vitta distinctly reddish to yellow in front, before lunule; male with hairs on outer (posterior) surface of fore tarsomeres short as usual; hind femur with only 2-3 anteroventral setae, confined to apical half, and no posteroventral setae (Fig. 23); male surstylus slightly dilated apically; distiphallus bend obtuse (Fig. 40); sternite 5 (Fig. 38).................... C. testacea (Robineau-Desvoidy, 1830)