[1] Sparnotheriodon and one species of Notiolofos, N. arquinotiensis, have been estimated to have had masses of roughly 400 kg (880 lb).

[8] Phylogenetic analyses conducted by Chimento and Agnolin in 2020 and Kramarz et al. 2021 both included one sparnotheriodontid, Victorlemoinea, and found it to be a basal litoptern.

[9][10] Unlike most authors, who treat sparnotheriodontids as a family, in 1997 McKenna and Bell classified them as a subfamily of Macraucheniidae.

[6] Soria regarded Heteroglyphis as a probable sparnotheriodontid,[14] but McKenna and Bell[15] and Bond et al.[16] included it in Anisolambdinae, with the former considering it a synonym of Protheosodon.

Sparnotheriodontids and astrapotheres are the only clades of terrestrial placental mammals confirmed to have lived in Antarctica.