After McKenna & Bell, 1997
<==o Megalonychidae Gervais, P., 1855 (kaksivarvaslaiskiaiset) [Synonyms]
|?- †Imagocnus MacPhee & Iturralde-Vinent, 1994
|--o †Ortotheriinae Ameghino, 1889 [Ortotheriidae Ameghino, 1889; Ortotheriinae Trouessart, 1898]
| |-- †Proschismotherium Ameghino, 1902
| |-- †Eucholoeops Ameghino, 1887
| |-- †Pseudortotherium Scillato-Yané, 1981
| |-- †Megalonychotherium Scott, 1904
| |-- †ParanabradysScillato-Yané, 1980
| |-- †Pliomorphus Ameghino, 1885
| |-- †Torcellia Kraglievich, 1923
| |-- †Ortotherium Ameghino, 1885 [Orthotherium Roger, 1887]
| |-- †Menilaus Ameghino, 1891
| |-- †Diodomus Ameghino, 1885 [Platyodon Ameghino,1881]
| |-- †Habanocnus Mayo, 1978
| `-- †Paulocnus Hooijer, 1962
`--o Megalonychinae Gervais, P., 1855 [Synonyms]
|?- †Pliometanastes Hirschfeld & Webb, 1968
|?- †Sinclairia Ameghino, 1912 [possibly synon. of Pliometanastes (McKenna & Bell, 1997)]
|?- †Megalonychops Kraglievich, 1926
|?- †Valgipes Gervais, 1874
|?- †Meizonyx Webb, 1985
|--o †Megalonychini Gervais, P., 1855 [Mégalonycidés Gervais, P., 1855; Megalonycidae Ameghino, 1889]
| |--o †Mesocnina Varona, 1974 [Mesocnini Varona, 1974; Mesocninae Arredondo, 1988; Mesocnina McKenna & Bell, 1997, +Cubanocnini Varona, 1974]
| | |--o †Neocnus Arredondo, 1961 [?Microcnus Matthew, 1931; ?Cubanocnus Kretzoi, 1968]
| | | |-- †N. major
| | | |-- †N. gliriformis [Microcnus gliriformis]
| | | |-- †N. comes
| | | |-- †N. dousman MacPhee, White & Woods, 2000
| | | `-- †N. toupiti MacPhee, White & Woods, 2000
| | `-- †Parocnus serus Miller, 1929 [?Mesocnus Matthew, 1931]
| `--o †Megalonychina Gervais, P., 1855 [Mégalonycidés Gervais, P., 1855; Megalonycidae Ameghino, 1889; Megalonycina Kraglievich, 1925]
| |--o †Megalocni Kraglievich, 1923 [Synonyms]
| | |--o †Megalocnus Leidy, 1868 [Myomorphus Pomel, 1868]
| | | |-- †M. rodens Leidy, 1868
| | | `-- †M. zile MacPhee, White & Woods, 2000
| | `-- †Neomesocnus Arredondo, 1961
| `--o †Megalonychi Gervais, P., 1855 [Mégalonycidés Gervais, P., 1855; Megalonycidae Ameghino, 1889]
| |-- †Protomegalonyx Kraglievich, 1925
| `--o †Megalonyx Harlan, 1825 [Synonyms]
| |-- †M. wheatleyi
| |-- †M. curvidens
| |-- †M. jeffersoni
| |-- †M. leidyi
| |-- †M. loxodon
| |-- †M. scalper
| `-- †M. tortulus
`--o Choloepodini Gray, 1871 [Choloepina Gray, 1871; Choloepodinae Gill, 1874; +Acratocnini Varona, 1974] (kaksivarpaislaiskiaiset)
|--o Choloepus Illiger, 1811 [Choloepodina Gray, 1871; Coeloepina Gray, 1871: Coeloepodina McKenna & Bell, 1997] ()?
| |-- C. didactylus (kaksivarvaslaiskiainen)
| `-- C. hoffmanni (hoffmanninlaiskiainen)
`--o †Acratocnina Varona, 1974 [Acratocnini Varona, 1974; Acratocnina McKenna & Bell, 1997]
|-- †Miocnus Matthew, 1931
|--o †Acratocnus Anthony, 1916
| |-- †A. odontrigonus Anthony, 1916
| `-- †A. ye MacPhee, White & Woods, 2000
`-- †Synocnus comes Paula Couto, 1967
Reference(s):
- Burkitt, J. H., 1995: Mammals: A world listing of living and extinct species.
–iNet: [This file no longer awailable, looking for new source and link]
- Carroll, R. L., 1988: Vertebrate paleontology and evolution.
–W. H. Freeman and company, New York, 1988, 698.
- Carroll, R. L., 1988: Appendix. 594-648.
in Carroll, R. L., 1988: Vertebrate paleontology and evolution.
–W. H. Freeman and company, New York, 1988, 698.
- MacPhee, R. D. E., White, J. L. & Woods, C. A., 2000: New megalonychid sloths (Phyllophaga: Xenarthra) from Quaternary of Hispaniola.
--American Museum Novitates: #3303, pp. 1-32
- McKenna, M. C. & Bell, S. K., (eds.) 1997: Classification of mammals – above the species level.
–Columbia University Press, New York, 1997, xii-631
- Nowak, R. M., 1991: Walker's Mammals of the World; Part 1.
–The Johns Hopkins University Press, Baltimore and London, 1991, xlviii-642-lxiii
- Nowak, R. M., 1991: Walker's mammals of the World; Part 2.
–The Johns Hopkins University Press, Baltimore and London, 1991, xii-643-1629