Stegomastodon

Stegomastodon Temporal range: Late Pliocene to Holocene
S. mirificus fossil at the Smithsonian natural history museum
Conservation status
Fossil
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Proboscidea
Family:	†Gomphotheriidae
Genus:	†Stegomastodon Pohlig, 1912
Species
†S. mirificus †S. primitivus

Stegomastodon ('roof breast tooth') is an extinct genus of gomphothere, a family of proboscideans. It is not to be confused with the genus Mammut from a different proboscidean family, whose members are commonly called "mastodons", nor with the genus Stegodon, from yet another proboscidean subfamily, whose members are commonly called "stegodonts".

Description

Restoration of S. mirificus

Skull

Stegomastodon mirificus is known from NMNH 10707, a 30-year-old male known from most of a skeleton. It was 2.6 metres (8.5 ft) tall, with a weight around 4.7 tonnes (4.6 long tons; 5.2 short tons). Like modern elephants, but unlike most of its closer relatives, it had just two tusks. These tusks curved upward and were about long. Stegomastodon's molars were covered in enamel and had a complex pattern of ridges and knobbly protrusions on them, giving the creature a large chewing surface that enabled it to eat grass. Its brain weighed about .

It lived in North and South America. The two South American species arrived following the Great American Interchange. They were initially mixed feeders; S. waringi evolved toward grazing, while S. platensis evolved toward browsing. The Stegomastodon species occupied warmer, lower-altitude habitats east of the Andes, while the related gomphothere Cuvieronius hyodon occupied cooler, higher-altitude habitats. It has been C14 dated to 27,910 BP in the Chapala Lake region, Jalisco, Mexico, as of now its most recent presence in North America, with its latest occurrence as recently as 6,060 BP in Yumbo, Valle del Cauca, Colombia.