Notiomastodon is an extinct genus of gomphothere proboscidean (related to modern elephants), endemic to South America from the Pleistocene to the beginning of the Holocene.[1] Notiomastodon specimens reached a size similar to that of the modern Asian elephant. Like other brevirostrine gomphotheres such as Cuvieronius and Stegomastodon, Notiomastodon had a shortened lower jaw and lacked lower tusks.
Notiomastodon was a generalist feeder capable of consuming various types of plants, which varied according to local environments. In the course of the last glacial period, there was an adaptation towards the consumption of grasses. 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.
Notiomastodon became extinct approximately 11,000 years ago at the end of the Pleistocene epoch. Specimens have been found associated with human artifacts, suggesting that hunting by recently arrived humans may have played a role in their extinction.