• Pionosyllis Malmgren, 1867
• Pionosyllis aciculata San Martín, 1990 accepted as Synmerosyllis aciculata (San Martín, 1990)
• Pionosyllis aciculigrossa San Martín, 1990 accepted as Syllis aciculigrossa (San Martín, 1990)
• Pionosyllis alternosetosa (Saint Joseph, 1886) accepted as Syllis armillaris (O.F. Müller, 1776)
• Pionosyllis ancori San Martín & Hutchings, 2006 accepted as Brevicirrosyllis ancori (San Martín & Hutchings, 2006)
• Pionosyllis anophthalma Capaccioni & San Martín, 1990 accepted as Perkinsyllis anophthalma (Capaccioni & San Martín, 1990)
• Pionosyllis anops Hartman, 1953 accepted as Eusyllis maxima (Monro, 1930)
• Pionosyllis articulata Kudenov & Harris, 1995 accepted as Paraehlersia articulata (Kudenov & Harris, 1995)
• Pionosyllis augeneri Hartmann-Schröder, 1979 accepted as Perkinsyllis augeneri (Hartmann-Schröder, 1979)
• Pionosyllis comosa Gravier, 1906 accepted as Pionosyllis kerguelensis (McIntosh, 1885)
• Pionosyllis compacta Malmgren, 1867
• Pionosyllis confusa Hartmann-Schröder, 1960 accepted as Nudisyllis pulligera (Krohn, 1852)
• Pionosyllis corallicola Ding & Westheide, 1997 accepted as Westheidesyllis corallicola (Ding & Westheide, 1997)
• Pionosyllis decorus Annenkova, 1934 accepted as Typosyllis adamanteus (Treadwell, 1914) accepted as Syllis adamantea (Treadwell, 1914)
• Pionosyllis dionisi Núñez & San Martín, 1991 accepted as Paraehlersia dionisi (Núñez & San Martín, 1991)
• Pionosyllis divaricata (Keferstein, 1862) accepted as Nudisyllis divaricata (Keferstein, 1862)
• Pionosyllis ehlersiaeformis Augener, 1913 accepted as Paraehlersia ehlersiaeformis (Augener, 1913)
• Pionosyllis elegans Pierantoni, 1903 accepted as Parapionosyllis elegans (Pierantoni, 1903)
• Pionosyllis elephantensis Hartmann-Schröder & Rosenfeldt, 1992 accepted as Pionosyllis dionisi Núñez & San Martín, 1991 accepted as Paraehlersia dionisi (Núñez & San Martín, 1991)
• Pionosyllis elongata Johnson, 1901 accepted as Syllis elongata (Johnson, 1901)
• Pionosyllis enigmatica (Wesenberg Lund, 1950) accepted as Pionosyllis nidrosiensis (Bidenkap, 1907)
• Pionosyllis epipharynx Hartman, 1953 accepted as Eusyllis maxima (Monro, 1930)
• Pionosyllis fusigera Augener, 1913 accepted as Paraopisthosyllis fusigera (Augener, 1913)
• Pionosyllis gesae Perkins, 1981 accepted as Westheidesyllis gesae (Perkins, 1981)
• Pionosyllis gestans Pierantoni, 1903 accepted as Parapionosyllis gestans (Pierantoni, 1903)
• Pionosyllis gigantea Moore, 1908
• Pionosyllis gorringensis Hartmann-Schröder, 1977 accepted as Brevicirrosyllis gorringensis (Hartmann-Schröder, 1977)
• Pionosyllis hartmannschroederae San Martín & Hutchings, 2006 accepted as Perkinsyllis hartmannschroederae (San Martín & Hutchings, 2006)
• Pionosyllis heterochaetosa San Martín & Hutchings, 2006
• Pionosyllis heterocirrata (Hartmann-Schröder, 1959) accepted as Westheidesyllis heterocirrata (Hartmann-Schröder, 1959)
• Pionosyllis homocirrata (Hartmann-Schröder, 1959) accepted as Perkinsyllis homocirrata (Hartmann-Schröder, 1958)
• Pionosyllis hyalina (Grube, 1863) accepted as Syllis hyalina Grube, 1863
• Pionosyllis kalimna San Martín & Hutchings, 2006 accepted as Paraopisthosyllis kalimna (San Martín & Hutchings, 2006)
• Pionosyllis kerguelensis (McIntosh, 1885)
• Pionosyllis koolalya San Martín & Hutchings, 2006
• Pionosyllis lamelligera Saint Joseph, 1887 accepted as Synmerosyllis lamelligera (Saint-Joseph, 1887)
• Pionosyllis lamelligera pariseta Ben-Eliahu, 1977
• Pionosyllis longisetosa (Hartmann-Schröder, 1990)
• Pionosyllis longisetosa Hartmann-Schröder, 1965 accepted as Perkinsyllis longisetosa (Hartmann-Schröder, 1965)
• Pionosyllis longocirrata Saint-Joseph, 1887 accepted as Opisthodonta longocirrata (Saint-Joseph, 1887)
• Pionosyllis lucida Chamberlin, 1919 (uncertain > nomen dubium)
• Pionosyllis luquei San Martín, 1990 accepted as Opisthodonta luquei (San Martín, 1990)
• Pionosyllis magnidens Day, 1953 accepted as Nudisyllis magnidens (Day, 1953)
• Pionosyllis magnifica Moore, 1906
• Pionosyllis malmgreni McIntosh, 1869
• Pionosyllis manca Treadwell, 1931
• Pionosyllis mariae San Martín & Hutchings, 2006 accepted as Brevicirrosyllis mariae (San Martín & Hutchings, 2006)
• Pionosyllis marquesensis Monro, 1939 accepted as Megasyllis marquesensis (Monro, 1939)
• Pionosyllis maxima Monro, 1930 accepted as Eusyllis maxima (Monro, 1930)
• Pionosyllis mayteae San Martín & Hutchings, 2006 accepted as Brevicirrosyllis mayteae (San Martín & Hutchings, 2006)
• Pionosyllis melaenonephra Haswell, 1920 accepted as Opisthodonta melaenonephra (Haswell, 1920)
• Pionosyllis micropharyngea Hartmann-Schröder, 1974 accepted as Megasyllis procera (Hartman, 1965)
• Pionosyllis minuta Pierantoni, 1903 accepted as Parapionosyllis minuta (Pierantoni, 1903)
• Pionosyllis morenoae San Martín, 1984 accepted as Pionosyllis longocirrata Saint-Joseph, 1887 accepted as Opisthodonta longocirrata (Saint-Joseph, 1887)
• Pionosyllis neapolitana Goodrich, 1930 accepted as Salvatoria neapolitana (Goodrich, 1930)
• Pionosyllis nidrosiensis (Bidenkap, 1907)
• Pionosyllis nutrix Monro, 1936 accepted as Salvatoria nutrix (Monro, 1936)
• Pionosyllis oculata Hartmann-Schröder, 1960 accepted as Brania arminii (Langerhans, 1881)
• Pionosyllis papillosa Pierantoni, 1903 accepted as Parapionosyllis papillosa (Pierantoni, 1903)
• Pionosyllis petalecirrus Averincev, 1982
• Pionosyllis pierantoni Cognetti, 1957 accepted as Pionosyllis weismanni Langerhans, 1879 accepted as Brevicirrosyllis weismanni (Langerhans, 1879)
• Pionosyllis pierantonii Cognetti, 1957 accepted as Pionosyllis weismanni Langerhans, 1879 accepted as Brevicirrosyllis weismanni (Langerhans, 1879)
• Pionosyllis pigmentata Chamberlin, 1919 accepted as Syllis pigmentata (Chamberlin, 1919)
• Pionosyllis procera Hartman, 1965 accepted as Megasyllis procera (Hartman, 1965)
• Pionosyllis prolifera (Krohn, 1852) accepted as Syllis prolifera Krohn, 1852
• Pionosyllis propeweismanni Dauvin & Lee, 1983 accepted as Palposyllis propeweismanni (Dauvin & Lee, 1983)
• Pionosyllis propreweismanni [auct.] accepted as Palposyllis prosostoma Hartmann-Schröder, 1977
• Pionosyllis pulligera (Krohn, 1852) accepted as Nudisyllis pulligera (Krohn, 1852)
• Pionosyllis riojai San Martín, 1990 accepted as Syllis riojai (San Martín, 1990)
• Pionosyllis rousei San Martín & Hutchings, 2006 accepted as Opisthodonta rousei (San Martín & Hutchings, 2006)
• Pionosyllis samsonensis Hartmann-Schröder, 1980 accepted as Nudisyllis tinihekea Knox & Cameron, 1970
• Pionosyllis serrata Southern, 1914 accepted as Nudisyllis pulligera (Krohn, 1852)
• Pionosyllis serratisetosa López, San Martín & Jiménez, 1997 accepted as Opisthodonta serratisetosa (López, San Martín & Jiménez, 1997)
• Pionosyllis spinisetosa San Martín, 1990 accepted as Perkinsyllis spinisetosa (San Martín, 1990)
• Pionosyllis stylifera Ehlers, 1912
• Pionosyllis subterranea Hartmann-Schröder, 1956 accepted as Salvatoria neapolitana (Goodrich, 1930)
• Pionosyllis suchumica Czerniavsky, 1881 (uncertain > nomen dubium)
• Pionosyllis templadoi San Martín, 1991 accepted as Opisthodonta templadoi (San Martín, 1991)
• Pionosyllis typica Moore, 1909 accepted as Typosyllis typica (Moore, 1909)
• Pionosyllis uraga Imajima, 1966 accepted as Opisthodonta uraga (Imajima, 1966)
• Pionosyllis uruga Imajima, 1966 accepted as Pionosyllis uraga Imajima, 1966 accepted as Opisthodonta uraga (Imajima, 1966)
• Pionosyllis weismanni Langerhans, 1879 accepted as Brevicirrosyllis weismanni (Langerhans, 1879)
• Pionosyllis weissmanni [auct.] accepted as Pionosyllis weismanni Langerhans, 1879 accepted as Brevicirrosyllis weismanni (Langerhans, 1879)
• Pionosyllis weissmannioides Augener, 1913 accepted as Paraehlersia weissmannioides (Augener, 1913)
• Pionosyllis yambaensis Hartmann-Schröder, 1990 accepted as Salvatoria euritmica (Sardá, 1984)
• Pionosyllis yolandae San Martín & Hutchings, 2006 accepted as Synmerosyllis yolandae (San Martín & Hutchings, 2006)