| Oligocene ( 87 ) |
| x | | | 1884 | Gaudry, A. (Halitherium Chouqueti, n.sp.; Paris Basin, France; 372-375.) |
| x | | | 1886b | Hartlaub, C. (Manatherium delheidi, n.gen.n.sp.; Belgium; 369-370.) |
| x | | | 1889 | Lefèvre, T. (fossil sirs.; Belgium; 197-200.) |
| x | | | 1892 | Lydekker, R. (Prorastoma veronense; [actually Eoc.] Italy; 77-78.) |
| x | | | 1914 | Rabell Cabrero, N. (indeterminate sir.; Puerto Rico; 66-69.) |
| x | D | | 1917 | Kermode, F. ("Desmostylus" [actually Cornwallius]; Vancouver Is., British Columbia; 42-43.) |
| x | D | | 1922 | Cornwall, I.E. ("Desmostylus" [actually Cornwallius]; British Columbia; 121-123.) |
| x | D | | 1922 | Hannibal, H. (Desmostylus; California & Oregon; 238-240.) |
| x | | | 1922a | Hay, O.P. (Metaxytherium floridanum, n.sp.; [actually Mioc.] Florida; 3.) |
| x | | | 1925 | Abel, O. (Halitherium Uytterhoeveni, n.sp.; Belgium; 39.) |
| x | | | 1932 | Müllerried, F.K.G. (indeterminate sir.; [actually Eoc.?] Chiapas, Mexico; 71-73.) |
| x | D | | 1935 | LaMotte, R.S. ("Desmostylus" sookensis; British Columbia; associated flora; 51-52.) |
| x | | | 1936 | Trelles-Duelo, L. (indeterminate sir.; Cuba; 269-270.) |
| x | | | 1937 | Venzo, S. (Halitherium bellunense; Late Olig., Italy; 7, 13, 196.) |
| x | D | | 1941b | VanderHoof, V.L. (Cornwallius; Baja California; 1985.) |
| x | D | | 1942a | VanderHoof, V.L. (Cornwallius sookensis; Baja California; 298-301.) |
| x | | | 1948 | Deraniyagala, P.E.P. (indeterminate sirs.; Libyan Desert, Egypt; m15.) |
| x | | | 1953 | Maldonado-Koerdell, M. (indeterminate sir.; [actually Eoc.?] Chiapas, Mexico; 146-148.) |
| x | | | 1956 | McKenna, M.C. (Lophiodolodus; Colombia; considered ?sir.; m739.) |
| | | | 1957 | Hunger & Magalowski |
| x | | | 1959 | Malde, H.E. (indeterminate sir.; South Carolina; 19, 21.) |
| | | * | 1959 | Spillmann, F. (Halitherium; Austria) |
| x | | | 1962 | Schäfer, W. (Halitherium schinzii; Mainz Basin, Germany; 53-56.) |
| x | | | 1962 | Wilhelm, W. (Halitherium schinzii; Mainz Basin, Germany; 51-53.) |
| | | | 1962 | Pietsch, K. (Germany) |
| x | D | | 1964 | Nolan, T.B. (Desmostylus; mA137.) |
| x | | | 1965 | Arata & Jackson (indeterminate sirs.; Mississippi; 175-177.) |
| x | | | 1970 | Chavanon & Saubade (Halitherium; France; 261-262.) |
| x | | | 1972 | Sittler, C. (Halitherium schinzii; France; 113.) |
| | | | 1973 | Mastrorilli, V.I. (Italy) |
| x | | * | 1973 | Spillmann, F. (Halitherium spp.; Austria; 197-209.) |
| | | | 1974 | May, J.H. (indeterminate sir.; Mississippi) |
| | | | 1975 | Rabeder, G. (Austria) |
| x | D | | 1976 | Phillips et al. (Desmostylus, Paleoparadoxia; Late Olig. [actually Early Mioc.?], Point Arena, California; 137, 152.) |
| x | | | 1977 | Tewari et al. ("Metaxytherium sp."; Late Olig., India; 45A-49A.) |
| x | | | 1978 | Satsangi & Trivedy (Halitherium sp.; Late Olig., India; 571-576.) |
| x | | | 1980 | Sanders, A.E. (cf. Halitherium, cf. Metaxytherium; Late Olig., South Carolina; 612.) |
| x | | | 1980 | Tobien, H. (Halitherium schinzii; Mainz Basin, Germany; stratigraphic occurrences; 207-209.) |
| | | | 1982 | Zammit-Maempel, G. (indet. sirs.; Early Olig., Malta) |
| | | | 1982 | Dockery, D.T., III (indeterminate sir.; Mississippi) |
| x | | | 1982 | Fischer, K. (Halitherium schinzii; Leipzig, Germany; 151-153.) |
| x | | | 1983 | Müller, A. (Halitherium schinzii; "Middle" Olig., Leipzig Bight, Germany; 71-72, pl. 27.) |
| | | * | 1984 | Okazaki, Y. (Dugongid(?) caudal vertebrae from the Late Oligocene Honjo Formation, Ashiya Group, Fukuoka, Japan.) |
| x | D | | 1986 | Applegate, S.P. (Cornwallius sookensis; Late Olig., Baja California; 157-158.) |
| x | D | | 1986 | Domning et al. (Behemotops, n.gen.; Washington & Oregon; 1-12, 23, 26.) |
| x | | | 1986 | Fleagle et al. (indeterminate sir.; Egypt; 8-9.) |
| x | | * | 1986 | Rothausen, K. (Germany; Halitherium schinzii, Anomotherium langewieschei; 520-521, 528-529, 545.) |
| | | | 1988 | Krüger, F.J. (Anomotherium langewieschei; Late Olig., Doberg, Germany) |
| x | D | | 1988 | Saito et al. (Behemotops sp.; Late Olig., Hokkaido, Japan; 269-273.) |
| x | | * | 1990 | MacPhee & Wyss (Puerto Rico; localities; 21, 27-36.) |
| | | | 1991 | Freess, W.B. (Halitherium schinzii; Germany) |
| x | | | 1992 | Gingerich, P.D. (Fayum, Egypt; stratigraphy, age, & paleoenvironments of sirs.; 67, 77.) |
| | D | | 1994 | Ray et al. (Behemotops proteus; Washington) |
| x | | | 1995 | Fichter, J. (Halitherium sp,; Late Olig., Germany; 154.) |
| x | | | 1995 | MacPhee & Iturralde-V. (indet. sir.; Early Olig., Puerto Rico; 15-16.) |
| x | | | 1997b | Domning, D.P. (Crenatosiren olseni; Late Oligocene, southeastern U.S.; 397-412.) |
| x | D | | 1997c | Domning, D.P. (Olig.-Mioc. boundary; biostratigraphic utility of sirs. & desmostylians; 178-179.) |
| x | | | 1998 | Lucas et al. (Kazakstan; Early Olig.; 320, 325-326, 346.) |
| | | | 1999 | Fichter, J. (Halitherium ?schinzii; Schauenburg-Hoof, Germany) |
| x | | | 1999 | Darga et al. (indeterminate sir.; Late Olig., Bavaria, Germany; 104-105.) |
| | | | 1999d | Domning, D.P. (Caribbean region; review; 29.) |
| x | | | 2001 | Böhme, M. (Halitherium; Early Olig., Leipzig Bight, Germany; 76-79.) |
| | | | 2005 | Cahuzac & Audouin (Halitherium schinzii; France; paleoecology) |
| | | * | 2006 | Bajpai et al. (Kutch) |
| | | | 2008 | Diedrich, C.G. (Anomotherium langewieschei, Halitherium schinzii; Germany) |
| x | | | 2008 | Rocher, P. (Rupelian, France; Halitherium schinzi; pl. 3.) |
| | | | 2008 | Voss, M. (Halitherium; Germany; Lower Olig.) |
| | D | | 2009 | Jacobs et al. (desmostylians; Alaska) |
| | D | * | 2009 | Beatty, B.L. (Cornwallius sookensis; Late Olig., Oregon) |
| x | | | 2010 | Micklich & Hildebrandt (Halitherium schinzii; Early Olig., Germany; 3, 13, 18, 19.) |
| | | | 2010 | Bizzarini & Reggiani (Halitherium schinzii; Olig., France; skull & dentition; reconstructed skeleton exhibited in Venice) |
| | | | 2011 | Voss, M. (Halitherium schinzii; Early Olig., Münsterland, Germany) |
| | | | 2011 | Bianucci et al. (Dugongidae indet.; Malta) |
| | | | 2011 | Boschele et al. (Dugongidae indet.; Early Olig., Italy) |
| | | | 2012 | Schöggl & Micklich (Halitherium schinzii; early Olig., Germany) |
| | | * | 2013 | Fanti & Forti (indet. sir.; Oligo-Miocene, Palawan, Philippines) |
| | | | 2013 | Reiter & Mittermayr (Halitherium cristolii; Late Olig., Linz, Austria) |
| | | | 2014 | Voss, M. |
| | | * | 2014a | Vélez-Juarbe & Domning (Metaxytherium albifontanum, n.sp.; Late Olig., Florida, South Carolina) |
| | | * | 2014b | Vélez-Juarbe & Domning (Priscosiren atlantica, n.gen.n.sp.; Early Olig., Puerto Rico & South Carolina) |
| | | * | 2015 | Vélez-Juarbe & Domning (Callistosiren boriquensis, n.gen.n.sp.; Late Olig., Puerto Rico) |
| | D | * | 2015 | Chiba et al. (Ounalashkastylus tomidai, n.gen.n.sp.; Olig.-Mioc., Alaska) |
| | D | * | 2015 | Beatty & Cockburn (Behemotops cf. proteus, Olig., Vancouver Is., British Columbia; Seuku, n.gen., Seuku emlongi, n.comb., Olig., Oregon) |
| x | | | 2015 | Coster et al. (indet. sir.; Early Olig., Sirt Basin, Libya; 50-52.) |
| | | | 2016 | Voss et al. (Austria; Lentiarenium cristolii) |
| | | * | 2019 | Domning & Beatty (Stegosiren macei n.gen.n.sp.; South Carolina) |
| | | | 2019 | Gol'din et al. (Dugongidae indet.; early Olig., Ukraine) |