Eionaletherium is an extinct genus of ground sloth from the Late Miocene coasts of Venezuela containing one species: E. tanycnemius.

Eionaletherium was discovered in the Late Miocene Urumaco Formation in the Falcón State of Venezuela and described in 2015 as a species of mylodontid ground sloth.

The holotype specimen, IVIC-P-2870, housed at the Venezuelan Institute for Scientific Research, comprises the femurs, a tibia, fibula, some vertebrae, and fragments of the scapulae, ribs, and the ankle bone.

[1] The genus name Eionaletherium comes from the Greek words eion (shore), ale (wanderer), and therium (beast), in reference to the nearshore environment it probably inhabited.

However, the bones are not particularly dense (pachyosteosclerosis) to negate buoyancy, and the femoral head is missing indicating it could not create powerful strokes necessary for swimming.