gomphotherium, closely related to mastodons disappeared before the end of the pleistocene. the 3 m (10 ft) tall creature, also known as trilophodon or tetrabelodon, resembled a modern elephant but had four tusks instead of two: two on the upper jaw and two on the elongated lower jaw. the lower ones are parallel and shaped like a shovel and were probably used as such. unlike modern elephants, the upper tusks were covered by a layer of enamel. these animals probably lived in swamps or near lakes,