Amebelodon
Encyclopedia
Amebelodon is a member of a diverse group of primitive proboscideans called gomphotheres, a group that also gave rise to the modern elephants and their close relative the mammoth
. The most striking attribute of this animal is its lower tusks, which are narrow, elongated,and distinctly flattened with the degree of flattening varying among the different species. Amebelodon first appeared in the Great Plains
and Gulf Coast regions of North America during the late Miocene
, roughly between 9 and 8 million years ago, and apparently became extinct on this continent sometime around 6 million years ago. It managed to migrate to Asia via the Bering land bridge
where it has been found in a number of late Miocene sites, particularly in China. The youngest record of Amebelodon is from a 5 million year old site in North Africa.
Amebelodon varied considerably in size. Amebelodon floridanus was smaller than a modern Asian elephant
, while Amebelodon britti, reached a shoulder height of 8 to 10 feet at the shoulder and a likely weight of 10 metric tons, similar to the largest mammoth
s and considerably larger than the living African elephant.
s, two uppers (much like those found on modern elephants), and two lowers that extended from the very front of the lower jaws. However, as mentioned above the lower tusks of Amebelodon were distinctive in that they were relatively long, slender, and flattened. Because of the resemblance of these lower tusks to shovels, Amebelodon is commonly referred to as a "shovel-tusked" gomphothere (another shovel-tusked gomphothere that may or may not be closely related to Amebelodon is Platybelodon
). There has long been an assumption that these lower tusks were actually used as shovels by the animal during feeding, presumably to scoop up water plants. However, an analysis of wear patterns has shown that these lower tusks were most likely used in a variety of ways in addition to shoveling, including scraping bark from trees. Overall, the evidence indicates that this animal was a versatile browser (an animal that eats broad-leaved plants rather than grass), feeding in both wet and dry settings in a variety of ways. For reasons that are not clearly explained in the literature, Amebelodon is usually portrayed with a short, flap-like trunk (this is true of the picture in the external link below). However, considerable evidence indicates that Amebelodon actually had a long, flexible trunk very much like that found in modern elephants, and that it probably was important for feeding.
Mammoth
A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of Elephantidae, the family of elephants and mammoths, and close relatives of modern elephants. They were often equipped with long curved tusks and, in northern species, a covering of long hair...
. The most striking attribute of this animal is its lower tusks, which are narrow, elongated,and distinctly flattened with the degree of flattening varying among the different species. Amebelodon first appeared in the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
and Gulf Coast regions of North America during the late 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...
, roughly between 9 and 8 million years ago, and apparently became extinct on this continent sometime around 6 million years ago. It managed to migrate to Asia via the Bering land bridge
Bering land bridge
The Bering land bridge was a land bridge roughly 1,000 miles wide at its greatest extent, which joined present-day Alaska and eastern Siberia at various times during the Pleistocene ice ages. Like most of Siberia and all of Manchuria, Beringia was not glaciated because snowfall was extremely light...
where it has been found in a number of late Miocene sites, particularly in China. The youngest record of Amebelodon is from a 5 million year old site in North Africa.
Species
Gomphotheres are notoriously difficult to identify with confidence down to the species level because of considerable intraspecific variation in the group, with a result that many named species are probably invalid. However, reasonably well established Amebelodon species include:- A. britti
- A. cyrenaicus
- A. floridanus
- A. fricki
Amebelodon varied considerably in size. Amebelodon floridanus was smaller than a modern Asian elephant
Asian Elephant
The Asian or Asiatic elephant is the only living species of the genus Elephas and distributed in Southeast Asia from India in the west to Borneo in the east. Three subspecies are recognized — Elephas maximus maximus from Sri Lanka, the Indian elephant or E. m. indicus from mainland Asia, and E. m....
, while Amebelodon britti, reached a shoulder height of 8 to 10 feet at the shoulder and a likely weight of 10 metric tons, similar to the largest mammoth
Mammoth
A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of Elephantidae, the family of elephants and mammoths, and close relatives of modern elephants. They were often equipped with long curved tusks and, in northern species, a covering of long hair...
s and considerably larger than the living African elephant.
Paleobiology
Like other typical gomphotheres, Amebelodon possessed two sets of tuskTusk
Tusks are elongated, continuously growing front teeth, usually but not always in pairs, that protrude well beyond the mouth of certain mammal species. They are most commonly canines, as with warthogs, wild boar, and walruses, or, in the case of elephants and narwhals, elongated incisors...
s, two uppers (much like those found on modern elephants), and two lowers that extended from the very front of the lower jaws. However, as mentioned above the lower tusks of Amebelodon were distinctive in that they were relatively long, slender, and flattened. Because of the resemblance of these lower tusks to shovels, Amebelodon is commonly referred to as a "shovel-tusked" gomphothere (another shovel-tusked gomphothere that may or may not be closely related to Amebelodon is Platybelodon
Platybelodon
Platybelodon was a genus of large herbivorous mammal related to the elephant . It lived during the Miocene Epoch, about 15-4 million years ago, and ranged over Africa, Europe, Asia and North America...
). There has long been an assumption that these lower tusks were actually used as shovels by the animal during feeding, presumably to scoop up water plants. However, an analysis of wear patterns has shown that these lower tusks were most likely used in a variety of ways in addition to shoveling, including scraping bark from trees. Overall, the evidence indicates that this animal was a versatile browser (an animal that eats broad-leaved plants rather than grass), feeding in both wet and dry settings in a variety of ways. For reasons that are not clearly explained in the literature, Amebelodon is usually portrayed with a short, flap-like trunk (this is true of the picture in the external link below). However, considerable evidence indicates that Amebelodon actually had a long, flexible trunk very much like that found in modern elephants, and that it probably was important for feeding.
