Notiomastodon

Notiomastodon Temporal range: late Early Pleistocene-Early Holocene (Possible Earliest Pleistocene record) ~0.8–0.011 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Skeleton at the Centro Cultural del Bicentenario de Santiago del Estero
Skull at the Natural History Museum, London
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Proboscidea
Family:	†Gomphotheriidae
Genus:	†Notiomastodon Cabrera, 1929
Species:	†N. platensis
Binomial name
†Notiomastodon platensis (Ameghino, 1888) [originally Mastodon]
Synonyms
Genus synonymy: Haplomastodon Hoffstetter 1950 Amahuacatherium Romero-Pittman, 1996 Species synonymy: List Elephas humboldtii Blainville, 1845 Mastodon platensis Ameghino, 1888 Mastodon superbus Ameghino, 1888 Mastodon bonaerensis Moreno, 1888 nomen nudum. Stegomastodon platensis Ameghino, 1888 Mastodon rectus Ameghino, 1889 Mastodon maderianus Ameghino, 1891 Notiomastodon ornatus Cabrera, 1929 Stegomastodon waringi Holland, 1920 Haplomastodon waringi Holland, 1920 Haplomastodon chimborazi Proaño, 1922 Haplomastodon guayasensis Hoffstetter, 1952 Amahuacatherium peruvium Romero-Pittman, 1996

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, 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.

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. Notiomastodon ranged widely over most of South America, from Colombia in the northwest to Northeast Brazil and southwards to the Zona Sur in Chile. It is thought to have been a generalist mixed feeder that fed on a variety of plants, with its diet varying according to local conditions. Like living elephants, Notiomastodon is thought to have lived in family groups, with adult males suggested to have had musth-like behaviour.

Notiomastodon became extinct approximately 11,000 years ago at the end of the Pleistocene epoch, simultaneously along with the majority of large (megafaunal) animals native to the Americas as part of the end-Pleistocene extinction event. During the last few thousand years of its existence, Notiomastodon lived alongside Paleoindians, the first human to inhabit the Americas. Specimens associated with artifacts suggest that humans hunted Notiomastodon, which may have been a factor in its extinction.