1	Compound chaetae with long blades; longer blades on each parapodium more than 3 times as long as shorter ones	2
–	Chaetae with shorter blades	3
2	Peristomium with a swelling partially covering the prostomium. Spines on long blades of compound chaetae short and straight. Two kinds of parapodial glands	Parapionosyllis brevicirra Day, 1954 (1)
–	Without swelling. Spines on long blades moderately long, distally dressed. Parapodial glands one kind, all with granular material	Parapionosyllis macaronesiensis Brito, Núñez & San Martín, 2000 (15)
3	Blades of uppermost compound chaetae in each parapodium twice as long as those of shortest chaetae, with long spines on margin	Parapionosyllis elegans (Pierantoni, 1903) (1)
–	Blades of uppermost compound chaetae on each parapodium more than twice as long as those of shortest chaetae, without long spines	4
4	Blades of uppermost compound chaetae distinctly longer than others on each parapodium, about 3 times longer than of the most ventral.	Parapionosyllis minuta (Pierantoni, 1903) (1)
–	Blades of uppermost compound chaetae longer than other blades on each parapodium but with a gradual and homogeneous gradation in size	Parapionosyllis cabezali Parapar, San Martín & Moreira, 2000 (1)