Stegodon

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Stegodon

Stegodon is a genus

Genus

A genus is a low-level taxonomic rank used in the classification of living and fossil organisms. The taxonomic ranks are domain , kingdom , phylum, class , order , family , genus, and species....
of the extinct subfamily Stegodontinae of the order

Order (biology)

In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
Proboscidea

Proboscidea

Proboscidea is an order containing only one family of living animals, Elephantidae, the elephants, with three living species .During the period of the last ice age there were more, now extinct species, including the genus of elephants Mammuthus and the elephant-like species the mastodons....
. Stegodonts lived in large parts of Asia

Asia

Asia is the world's largest and most populous continent. It covers 8.6% of the Earth's total surface area and, with over 4 billion people, it contains more than 60% of the world's current human population....
during the Pliocene

Pliocene

The Pliocene epoch is the period in the geologic timescale that extends from 5.332 million to 1.806 million years before present.The Pliocene is the second epoch of the Neogene period in the Cenozoic era....
and Pleistocene

Pleistocene

The Pleistocene is the epoch from 1.8 million to 10,000 years Before Present covering the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
epochs. Some Stegodon species were among the largest of all Proboscidea, with adults being 13 feet high at the shoulder, 26 feet long, not including 10 feet long nearly straight tusks. In some individuals the tusks were so close together that the trunk probably did not lie between them but instead draped over.

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Encyclopedia

Stegodon is a genus

Genus

Order (biology)

In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
Proboscidea

Proboscidea

Asia

Pliocene

Pleistocene

Dwarf elephant

Fossil remains of dwarf elephants have been found on the Mediterranean islands of Cyprus, Malta , Crete, Sicily, Sardinia, the Cyclades and the Dodecanese Islands....
population survived until 12,000 years ago on the Island of Flores

Flores

Flores is one of the Lesser Sunda Islands, an island arc with an estimated area of 14,300 km? extending east from the Java island of Indonesia....
. A review of 130 papers written about 180 different sites with Proboscidea remains in southern China revealed Stegodons to have been more common than Asian Elephants; the papers gave many recent radiocarbon dates, the youngest being 2,150 B.C. (4,100 BP). The name Stegodon is derived from the Greek

Greek language

Greek is an Indo-European languages native to the southern Balkan peninsula, the language of the Greek people. It forms an independent branch within Indo-European....
words ste?e?? stegein ('to cover') and ?d?? odοn ('tooth

Tooth

Teeth are small whitish structures found in the jaws of many vertebrates that are used to tear, scrape, and chew food. Some animals, particularly carnivores, also use teeth for hunting or defense....
') because of the distinctive ridges on the animal's 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"....
s.

Relationship

In the past, stegodonts were believed to be the ancestor

Ancestor

An ancestor is a parent or the parent of an ancestor .Two individuals have a genetics relationship if one is the ancestor of the other, or if they share a common ancestor....
s of the true elephant

Elephant

Elephants are large land mammals of the order Proboscidea and the family Elephantidae. There are three living species: the African Bush Elephant, the African Forest Elephant and the Asian Elephant ....
s and mammoth

Mammoth

A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of the Elephantidae and close relatives of modern elephants....
s, but it is currently believed that they have no modern descendants. Stegodon is derived from the genus Stegolophodon
Stegolophodon

Stegolophodon is an extinct genus of Proboscidean. Stegolophodon was a Gomphothere with four tusks and a Elephant#Trunk. It lived in the Miocene and Pliocene Epochs, and may have evolved from Stegodon....
, an extinct genus known from the Miocene of Asia. Stegodon is considered to be a sister group of the mammoth, as well as the elephants. Some taxonomists

Taxonomy

Taxonomy is the practice and science of classification. The word comes from the Greek language ', taxis and ', nomos .Taxonomies, or taxonomic schemes, are composed of taxonomic units known as taxa , or kinds of things that are arranged frequently in a hierarchical structure....
consider the stegodonts as a subfamily of the Elephantidae. Both Stegolophodon
Stegolophodon

Stegolophodon is an extinct genus of Proboscidean. Stegolophodon was a Gomphothere with four tusks and a Elephant#Trunk. It lived in the Miocene and Pliocene Epochs, and may have evolved from Stegodon....
and primitive elephants were derived from the Gomphotheriidae. The most important difference between Stegodon and the Elephantidae can be observed in the molars

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"....
. Molars of stegodonts consist of a series of low, roof-shaped ridges, whereas in elephants each ridge has become a high-crowned plate. Furthermore, the skeletons of stegodonts are more robust and compact than those of elephants.

In the Bardia National Park in Nepal

Nepal

Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia and is the world's youngest republic. It is bordered to the north by the People's Republic of China, and to the south, east, and west by India....
, there is a population of Indian Elephants which, due to inbreeding

Inbreeding

Inbreeding is biological reproduction between close Kinships, whether plant or animal. If practiced repeatedly, it leads to an increase in homozygosity of a population....
are very similar to Stegodon and may retain many Stegodon features. Some dismiss these primitive features as recent mutation

Mutation

In biology, mutations are changes to the nucleotide sequence of the genetic material of an organism. Mutations can be caused by copying errors in the genetic material during cell division, by exposure to ultraviolet or ionizing radiation, chemical mutagens, or virus , or can be induced by the organism, itself, by cellular processes such as s...
s rather than atavism

Atavism

The term atavism denotes the tendency to revert to ancestral type. An atavism is an evolutionary throwback, such as traits reappearing which had disappeared generations ago....
s.

Dwarfing on islands

Like elephants, stegodonts must have been good swimmers. Their fossil

Fossil

Fossils are the preserved remains or trace fossil of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous Rock formations and sedimentary rock layers is known as the fossil record....
s are frequently encountered on Asian islands, which even during periods of low sea-level (during the cold phases of the Pleistocene

Pleistocene

Land bridge

A land bridge, in biogeography, is an isthmus or wider land connection between otherwise separate areas, which allows terrestrial animals and plants to cross over and colonise new lands....
s with the Asian continent (Sulawesi

Sulawesi

Sulawesi is one of the four larger Sunda Islands of Indonesia and is situated between Borneo and the Maluku Islands....
, Flores

Flores

Flores is one of the Lesser Sunda Islands, an island arc with an estimated area of 14,300 km? extending east from the Java island of Indonesia....
, Timor

Timor

Timor is an island at the south end of the Malay Archipelago, north of the Timor Sea. It is divided between the independent state of East Timor, , and West Timor, belonging to the Indonesian province of East Nusa Tenggara....
, Sumba

Sumba

Sumba is an island in Indonesia, and is one of the Lesser Sunda Islands. It has an area of 11,153 km?, and the population was officially at 611,422 in 2005....
in Indonesia

Indonesia

The Republic of Indonesia , is a transcontinental country in Southeast Asia and Oceania. Comprising Islands of Indonesia, it is the world's largest Archipelago state....
, Luzon

Luzon

Luzon is the largest and most economically and politically important island in the Philippines and one of the three island groups in the country, with Visayas and Mindanao being the other two....
and Mindanao

Mindanao

Mindanao is the second largest and easternmost island in the Philippines. It is also one of the three island groups in the country, along with Luzon and Visayas....
in the Philippines

Philippines

The Philippines, officially known as the Republic of the Philippines, is a country in Southeast Asia with Manila as its capital city. It comprises 7,107 islands in the western Pacific Ocean....
and in Taiwan

Taiwan

Taiwan is an island in East Asia. "Taiwan" is also commonly used to refer to the country governed by the Republic of China and to the ROC itself, which governs the island of Taiwan, Orchid Island and Green Island, Taiwan in the Pacific Ocean off the Taiwan coast, the Penghu islands in the Taiwan Strait, and Kinmen and the Matsu Islands...
and Japan

Japan

Japan is an island country in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, People's Republic of China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south....
). A general evolutionary trend in large mammals on islands is island dwarfing. The smallest dwarf species, Stegodon sondaari, known from 900,000 year old layers on the Indonesian island of Flores, had an estimated bodyweight comparable to a water buffalo. Another dwarf species lived on Flores more recently, and was contemporaneous with the hominin discovered in 2003, Homo floresiensis
Homo floresiensis

Homo floresiensis is a possible species in the genus Homo , remarkable for its small body and brain and for its survival until relatively recent times....
. Stegodon tetrabelodon syrticus was a spectacular late Miocene species with four tusks described from a partial cranium and jaws found in North Africa

There are twelve known species of Stegodon:

Stegodon elephantoides (Myanmar
Myanmar

Burma, officially the Union of Myanmar, is the largest country by geographical area in mainland Southeast Asia, or Indochina. The country is bordered by the People's Republic of China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, and the Bay of Bengal to the southwest with...
, Java)
Stegodon sompoensis (Sulawesi
Sulawesi

Sulawesi is one of the four larger Sunda Islands of Indonesia and is situated between Borneo and the Maluku Islands....
, Indonesia)
Stegodon aurorae (Japan
Japan

Japan is an island country in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, People's Republic of China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south....
) - Aurora's Stegodont
Stegodon ganesha (India
India

India, officially the Republic of India , is a country in South Asia. It is the List of countries and outlying territories by total area country by geographical area, the List of countries by population country, and the most populous liberal democracy in the world....
, Pakistan
Pakistan

Pakistan , officially the Islamic Republic of Pakistan, is a country located in South Asia and borders Central Asia and the Middle East. It has a 1,046 kilometre coastline along the Arabian Sea and Gulf of Oman in the south, and is bordered by Afghanistan and Iran in the west, India in the east and People's Republic of China in th...
)
Stegodon insignis (Pakistan)
Stegodon zdanski (China
China

China is a Culture of China, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
)
Stegodon orientalis (China, Japan) - Oriental Stegodont
Stegodon shinshuensis (Japan) - Japanese Stegodont
Stegodon trigonocephalus (Java, Indonesia)
Stegodon sondaari (Flores, Indonesia)
Stegodon tetrabelodon syrticus (Shabi, Libya)
Stegodon florensis (Flores, Indonesia)