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, while the only other gomphothere in South America, Cuvieronius, was confined to the northwestern part of the continent. Gomphotheres like Notiomastodon arrived in South America along with many other animals of North American origin as part of the Great American Interchange following the formation of the Isthmus of Panama connecting the two continents during the Pliocene epoch, with the earliest records of gomphotheres in South America dating to the beginning of the Pleistocene around 2.5 million years ago, though the first records unambiguously attributable to Notiomastodon appear around 560,000 years ago. Notiomastodon represented one of the largest animals in South America along with the comparably sized giant ground sloths Megatherium and Eremotherium. Notiomastodon ranged widely over most of South America, from Colombia in the northwest to Northeast Brazil and southwards to the Zona Sur in Chile in environments ranging from scrubland to rainforest. It is thought to have been a generalist mixed feeder that fed on a variety of plants including leaves, grasses and fruit, with its diet varying according...