Taxonomy Classification Sparassodonts can be divided into six major groups; basal sparassodonts (?earliest Paleocene-late Miocene), species that cannot be easily assigned to any of the other sparassodont groups and whose teeth often exhibit adaptations for omnivory; hathliacynids (late Oligocene-early Pliocene/late Pliocene), which range from a marten to a thylacine in size, and have long, fox-like snouts and teeth strongly adapted for carnivory; basal borhyaenoids (middle Eocene-late Miocene), borhyaenoids that cannot be easily classified into the families Borhyaenidae, Thylacosmilidae, or Proborhyaenidae and vary in size and shape; borhyaenids (early-late Miocene), the sparassodont group most specialized for running, but not as much as living carnivorans or even thylacines; proborhyaenids (middle Eocene-late Oligocene), robust, wolverine-like forms with ever-growing upper and lower canines; and thylacosmilids (early Miocene-late Pliocene), another terrestrially specialized group with ever-growing saber-like upper canines. The taxonomic classification below follows the latest review of the group, that of Prevosti and Forasiepi (2018), with additions from more recent studies. Although Mayulestes was originally described as a sparassodont, later phylogenetic analyses have shown that it most likely does not belong to this group; however more recent studies show it to be closely related to sparassodonts. Similarly, while basal borhyaenoids such as Lycopsis and Prothylacynus were once thought to belong to a distinct family (Prothylacynidae), phylogenetic analyses have found that these animals do not represent a monophyletic group. The exact age of most Eocene species of sparassodonts is uncertain, given the lack of precise stratigraphic information associated with most specimens and the recent division of the Casamayoran SALMA into the Vacan and Barrancan SALMAs. Order Sparassodonta Genus Allqokirus Allqokirus australis (earliest Paleocene, Tiupampan SALMA) Genus Mayulestes Mayulestes ferox (earliest Paleocene, Tiupampan SALMA) Genus Argyrolestes Genus Nemolestes Nemolestes spalacotherinus (late middle Eocene, Barrancan SALMA) Genus Patene Patene campbelli (late ?Eocene, Santa Rosa local fauna) Patene coloradensis (middle Eocene) Patene coluapiensis (middle Eocene, Barrancan SALMA) Patene simpsoni (late Paleocene/early Eocene, Itaboraian SALMA) Genus Procladosictis Procladosictis anomala (late Eocene, Mustersan SALMA) Family Hondadelphidae Genus Hondadelphys Hondadelphys fieldsi (late middle Miocene, Laventan SALMA) Genus Stylocynus Stylocynus paranensis (latest Miocene, Huayquerian SALMA) Family Hathliacynidae Genus Acyon Acyon ?herrerae (early Miocene, Colhuehuapian SALMA) Acyon myctoderos (late middle Miocene, Laventan SALMA) Acyon tricuspidatus (late early Miocene, Santacrucian SALMA) Genus Australogale Australogale leptognathus (late middle Miocene, Laventan SALMA) Genus Borhyaenidium Borhyaenidium altiplanicus (latest Miocene, Huayquerian SALMA) Borhyaenidium riggsi (unknown, either early or late Pliocene, Montehermosan or Chapadmalalan SALMA) Borhyaenidium musteloides (latest Miocene, Huayquerian