After McKenna & Bell, 1997, with Recent species from Nowak, 1991

<==o Sigmodontini Wagner, 1843 (cotton rats; puuvillarotat) [taxonomic history]
   |--o †Prosigmodon Jacobs & Lindsey, 1981; E.Plioc. NA.
   |  |-- †P. holocuspis Czaplewski, 1987
   |  |-- †P. chihuahuensis
   |  `-- †P. oroscoi
   `--o Sigmodon Say & Ord, 1825 [Hesperomys (Sigmodon) Say & Ord, 1825; Lasiomys Burmeister, 1854; Deilemys de Saussure, 1860; Sigmomys Thomas, 1901] E.Plioc.-R. NA., R. SA. CA. (cotton rats)
      |-- †S. curtisi Gidley, 1922
      |-- †S. minor Gidley, 1922 [S. medius Gidley, 1922]
      |-- S. hispidus (jäykkäkarvapuuvillarotta, puuvillarotta)
      |-- S. alleni (ruskopuuvillarotta)
      |-- S. leucotis ()?
      |-- S. ochrognathus ()?
      |-- S. mascotensis ()?
      |--o S. arizonae ()?
      |  |-- S. a. arizonae ()?
      |  `-- S. a. plenus ()?
      |-- S. fulviventer ()?
      |-- S. alstoni ()?
      |?- S. inopinatus ()?
      `?- S. peruanus ()?

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