Metamynodon
Encyclopedia
Metamynodon is an extinct genus
of amynodont
perissodactyls, and is among the longest lived genera of amynodonts, having first appeared during the late Eocene
, and becoming extinct during the early Miocene
, when it was supplanted by the semiaquatic rhinoceros, Teleoceras
. Its fossils have been discovered in the United States
(White River Fauna
), Mongolia
and China
.
Metamynodon was about 4 metres (13.1 ft) in body length, and, although it was distantly related to the modern rhinoceros
, looked more like a hippopotamus
. Its front legs had four toes instead of the three found in modern rhinos. Although it was a herbivore (as indicated by its teeth), its skull had a bony ridge typically associated with carnivorous mammals. It probably fed on tough plant material, and the jaw muscles were attached to this ridge. Metamynodon would have used its enlarged canines
to search for food in river banks, and may also have had highly flexible lips. Its eyes were placed high on the skull, meaning that it would have been able to see while almost fully submerged, much like a hippopotamus or crocodile
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of amynodont
Amynodontidae
The Amynodonts were a group of hippo-like perissodactyls, related to true rhinoceri, that were descended from the Hyracodontidae. They ranged from North America, Europe and Asia during the Late Eocene to Miocene living from 46.2 Ma—7 Ma years ago and existed for approximately .The last species died...
perissodactyls, and is among the longest lived genera of amynodonts, having first appeared during the late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
, and becoming extinct during 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...
, when it was supplanted by the semiaquatic rhinoceros, Teleoceras
Teleoceras
Teleoceras is an extinct genus of grazing rhinoceros that lived in North America during the Miocene epoch, which ended about 5.3 million years ago, all the way to the early Pliocene epoch....
. Its fossils have been discovered in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
(White River Fauna
White River Fauna
The White River Fauna are fossil animals found in the White River Badlands of South Dakota, Wyoming and Nebraska in the United States including the Badlands National Park. The fossils have been found in the Chadron, Brule, and the Arikaree Formations...
), Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
and China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
.
Characteristics
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....
, looked more like a hippopotamus
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...
. Its front legs had four toes instead of the three found in modern rhinos. Although it was a herbivore (as indicated by its teeth), its skull had a bony ridge typically associated with carnivorous mammals. It probably fed on tough plant material, and the jaw muscles were attached to this ridge. Metamynodon would have used its enlarged canines
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
to search for food in river banks, and may also have had highly flexible lips. Its eyes were placed high on the skull, meaning that it would have been able to see while almost fully submerged, much like a hippopotamus or crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
.