Notiomastodon

Notiomastodon is an extinct genus of gomphothere proboscidean (related to modern elephants), endemic to South America from the Pleistocene to the early Holocene. Individuals of Notiomastodon reached a size similar to that of the modern Asian elephant, with a body mass of 3-4 tonnes. Like other brevirostrine gomphotheres such as Cuvieronius and Stegomastodon, Notiomastodon had a shortened lower jaw and lacked lower tusks, unlike more primitive gomphotheres like Gomphotherium.

The genus was originally named in 1929, and has been controversial in the course of taxonomic history as it has frequently been confused with or synonymized with forms called Haplomastodon and Stegomastodon. Extensive anatomical studies since the 2010s have shown that Notiomastodon represents the only valid proboscidean in lowland South America, Haplomastodon is synonymous and Stegomastodon is limited to North America, with the only other gomphothere in South America Cuvieronius confined to the northwestern part of the continent.