In synonymy:
Ctenopsis Schmidt, 1956 = Isoctenus Bertkau, 1880 (Polotow & Brescovit, 2009a: 586)

type Isoctenus foliifer Bertkau, 1880; gender masculine

N.B.: removed from the synonymy of Ctenus Walckenaer, 1805 by Lehtinen, 1967: 241 (contra Petrunkevitch, 1928: 226 and Roewer, 1955c: 650; synonymy not accepted by Mello-Leitão, 1936d: 2, 18 and Bonnet, 1957: 2311); considered a senior synonym of Ctenopsis Schmidt, 1956a: 28 [urn:lsid:nmbe.ch:spidergen:01784] (type C. stellata Schmidt, 1956) by Polotow & Brescovit, 2009a: 586.

Transferred to other genera:
Isoctenus masculus Mello-Leitão, 1939 -- see Parabatinga
Isoctenus sigma Schenkel, 1953 -- see Ctenus

In synonymy:
Isoctenus cinnamoneus (C. L. Koch, 1847) = Isoctenus janeirus (Walckenaer, 1837) (Petrunkevitch, 1911: 474, sub Ctenus).
Isoctenus mourei (Mello-Leitão, 1947, T from Ctenus) = Isoctenus herteli (Mello-Leitão, 1947) (Polotow & Brescovit, 2009a: 601).
Isoctenus pauper (Mello-Leitão, 1947, T from Ctenus = Isoctenus strandi Mello-Leitão, 1936 (Polotow & Brescovit, 2009a: 602).
Isoctenus sanguineus (Walckenaer, 1837, T from Ctenus) = Isoctenus janeirus (Walckenaer, 1837) (Polotow & Brescovit, 2009a: 595).
Isoctenus semiornatus (Mello-Leitão, 1939, T from Ctenus) = Isoctenus janeirus (Walckenaer, 1837) (Polotow & Brescovit, 2009a: 595).
Isoctenus stellatus (Schmidt, 1956, T from Ctenopsis) = Isoctenus janeirus (Walckenaer, 1837) (Polotow & Brescovit, 2009a: 595).
Isoctenus velocitatis (Roewer, 1951, T from Ctenus) = Isoctenus coxalis (F. O. Pickard-Cambridge, 1902) (Polotow, Brescovit & Pellegatti-Franco, 2005: 38).

Homonym replaced:
Isoctenus velox (Keyserling, 1891) -- see Isoctenus coxalis (see F. O. Pickard-Cambridge, 1902b)

Nomen dubium:
Isoctenus latevittatus Caporiacco, 1954: 125 (j, French Guiana) -- Polotow & Brescovit, 2009a: 590.

Isoctenus areia Polotow & Brescovit, 2009a: 595, f. 6A-D (Dmf).

Isoctenus botocudos Pontes Moraes et al., 2023: 183, f. 5A-B, 6A-B (Dm).

Isoctenus cabula Pontes Moraes et al., 2023: 181, f. 3A-D, 4A-D (Dmf).

Isoctenus charada Polotow & Brescovit, 2009a: 600, f. 12A-D (Dmf).

Isoctenus corymbus Polotow, Brescovit & Pellegatti-Franco, 2005: 40, f. 6-9 (Dmf).

Ctenus velox Keyserling, 1891: 147, pl. 4, f. 100 (Dm; preoccupied by Blackwall, 1865, see Afroneutria velox) [urn:lsid:nmbe.ch:spidersp:062511].
Ctenus coxalis F. O. Pickard-Cambridge, 1902b: 413 (replacement name).
Ctenus velox Mello-Leitão, 1936a: 14, pl. 3, f. 28-29 (m).
Isoctenus janeirus Mello-Leitão, 1936a: 20, pl. 2, f. 42 (f; misidentified per Polotow & Brescovit, 2009a: 596).
Ctenus velocitatis Roewer, 1951: 446 (superfluous replacement name) [urn:lsid:nmbe.ch:spidersp:062512].
Isoctenus coxalis Polotow, Brescovit & Pellegatti-Franco, 2005: 38, f. 1-5 (m, Df, T from Ctenus, S of Ctenus velocitatis).
Isoctenus coxalis Polotow & Brescovit, 2009a: 596, f. 3A-D, 18A, 19F, 20D (mf).
Isoctenus coxalis Polotow & Brescovit, 2014: 353, f. 13C, 17E (f).

Isoctenus eupalaestrus Mello-Leitão, 1936a: 18, pl. 3, f. 39-40 (Dm).
Ctenus pauper Mello-Leitão, 1947b: 271 (1f paralectotype; misidentified per Polotow & Brescovit, 2009a: 599).
Ctenus eupalaestrus Roewer, 1955c: 649.
Isoctenus eupalaestrus Polotow & Brescovit, 2009a: 599, f. 10A-D, 19A (mf).

Isoctenus foliiferus Bertkau, 1880a: 61 (Dj).
Ctenus foliiferus Keyserling, 1891: 154.
Isoctenus foliiferus Lehtinen, 1967: 241 (T from Ctenus).
Isoctenus foliifer Polotow & Brescovit, 2009a: 590, f. 4A-D, 19E (Dmf).
Isoctenus foliifer Polotow & Brescovit, 2014: 352, f. 12A (m).

Ctenus griseolus Mello-Leitão, 1936a: 7, pl. 1, f. 8, pl. 2, f. 6-7 (Dm).
Isoctenus griseolus Polotow & Brescovit, 2009a: 597, f. 7A-D (m, Df, T from Ctenus).

Ctenus guadalupei Mello-Leitão, 1941f: 215, f. 23-24 (Df).
Isoctenus guadalupei Polotow & Brescovit, 2019b: 292, f. 1A-D, 2A-C (Dm, f, T from Ctenus).

Ctenus herteli Mello-Leitão, 1947b: 269, pl. 37, f. 24 (Df).
Ctenus mourei Mello-Leitão, 1947b: 270, pl. 37, f. 25 (Dm; 1m paralectotype see Isoctenus strandi) [urn:lsid:nmbe.ch:spidersp:020637].
Isoctenus herteli Polotow & Brescovit, 2009a: 601, f. 13A-D (mf, T from Ctenus, S of Ctenus mourei).

Ctenus janeirus Walckenaer, 1837: 364 (Df).
Ctenus sanguineus Walckenaer, 1837: 365 (Df) [urn:lsid:nmbe.ch:spidersp:020682].
Ctenus cinnamoneus C. L. Koch, 1847: vol. 15: 58, f. 1457 (Dj) [urn:lsid:nmbe.ch:spidersp:062513].
Ctenus janeirus Petrunkevitch, 1911: 474 (S of Ctenus cinnamoneus).
Ctenus semiornatus Mello-Leitão, 1939f: 526, f. 7-8 (Df) [urn:lsid:nmbe.ch:spidersp:020687].
Ctenopsis stellata Schmidt, 1954: 420, f. 13a-b (f, nomen nudum).
Ctenopsis stellata Schmidt, 1956a: 29, f. 4 (Df) [urn:lsid:nmbe.ch:spidersp:020472].
Isoctenus janeirus Polotow & Brescovit, 2009a: 594, f. 5A-D, 19G (Dm, f, T from Ctenus, S of Ctenopsis stellata, Ctenus sanguineus and C. semiornatus).

Isoctenus jussara Pontes Moraes et al., 2023: 178, f. 1A-D, 2A-D (Dmf).

Isoctenus malabaris Polotow, Brescovit & Ott, 2007: 216, f. 1-5 (Dmf).
Isoctenus malabaris Polotow & Brescovit, 2009a: 603, f. 19D (m).

Ctenus minusculus Keyserling, 1891: 149, pl. 4, f. 102 (Df).
Ctenus minusculus Mello-Leitão, 1936a: 11, pl. 1, f. 16, pl. 2, f. 17-18 (f, Dm).
Isoctenus minusculus Polotow & Brescovit, 2009a: 601, f. 14A-D, 19B (mf, T from Ctenus).

Ctenus sanguineus Mello-Leitão, 1936a: 12, pl. 1, f. 24 (f; misidentified per Polotow & Brescovit, 2009a: 598).
Isoctenus ordinario Polotow & Brescovit, 2009a: 598, f. 9A-D, 19H-I (Dmf).

Isoctenus segredo Polotow & Brescovit, 2009a: 600, f. 11A-D (Dmf).

Isoctenus strandi Mello-Leitão, 1936a: 20, pl. 2, f. 43 (Df).
Ctenus pauper Mello-Leitão, 1947b: 271, pl. 37, f. 26-27 (Df; 1f paralectotype see Isoctenus eupalaestrus) [urn:lsid:nmbe.ch:spidersp:020653].
Ctenus mourei Mello-Leitão, 1947b: 270 (1m paralectotype; misidentified per Polotow & Brescovit, 2009a: 602).
Isoctenus strandi Polotow & Brescovit, 2009a: 602, f. 15A-D, 19C (mf, S of Ctenus pauper).

Ctenus taperae Mello-Leitão, 1936a: 13, pl. 3, f. 25-26 (Dm).
Isoctenus taperae Polotow & Brescovit, 2009a: 598, f. 8A-B (m, T from Ctenus).