Key to Polycirrus species from the coasts of Türkiye

1. Prostomial lateral processes present....................................................................... 2

- Prostomial lateral processes absent....................................................................... 3

2. 30 notochaetigerous segments...................................................................... P. twisti

- 6 notochaetigerous segments........................................................... P. karadenizicus n. sp.

3. Upper lip with only a medial lobe........................................................................ 4

- Upper lip trefoiled.......................................................................... P. aurantiacus

4. Upper lip long, 2-2.5 times longer than wide...................................................... P. haematodes

- Upper lip small, wider than long....................................................... P. rhombolabiatus n. sp.