Chilgatherium is the earliest and most primitive representative of the family Deinotheriidae

Deinotheriidae

Deinotheriidae is a family of prehistoric elephant-like proboscideans that lived during the Tertiary period, first appearing in Africa, then spreading across southern Asia and Europe. During that time they changed very little, apart from growing much larger in size - by the late Miocene they had...

. It is known from late Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 (27 to 28 million years old) fossil teeth found in the Ethiopia

Ethiopia

Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...

n district of Chilga

Chilga

Chilga is one of the 105 woredas in the Amhara Region of Ethiopia. It is named after its chief town Chilga , an important stopping point on the historic Gondar-Sudan trade route...

. So far, only a number of molar

Molar (tooth)

Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....

 teeth

Tooth

Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...

 have been found, but these are distinct enough that this animal can be identified with confidence. The teeth differ from those of Prodeinotherium

Prodeinotherium

Prodeinotherium is an early representative of the family Deinotheriidae, that lived in Africa, Europe, and Asia in the early and middle Miocene. It was the size of a small elephant, about 9 feet at the shoulders, but differed from elephants in possessing a pair of downward curving tusks on the...

, Deinotherium

Deinotherium

Deinotherium , also called the Hoe tusker, was a large prehistoric relative of modern-day elephants that appeared in the Middle Miocene and continued until the Early Pleistocene. During that time it changed very little...

, and the various barytheres in various details, enough to show that this is a distinct type of animal, and has been placed in its own subfamily. Compared to later deinotheres, Chilgatherium was quite small, about midway between a large pig

Pig

A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

 and a small hippo

Hippopotamus

The hippopotamus , or hippo, from the ancient Greek for "river horse" , is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae After the elephant and rhinoceros, the hippopotamus is the third largest land mammal and the heaviest...

 in size. It is not known if it shared the distinctive downward-curving tusks on the lower jaw that the later deinotheres had.

Chilgatherium disappears prior to the Early Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

, where Prodeinotherium occurs instead.