|
Stegoloxodon
''Stegoloxodon'' is an extinct genus of dwarf elephant known from the Early Pleistocene of Indonesia. It contains two species, ''S. indonesicus'' from Java, and ''S. celebensis'' from Sulawesi. Its relationship with other elephants is uncertain. Taxonomy ''S. celebensis'' was originally described as ''Archidiskodon'' ''celebensis'' in 1949 by Dirk Albert Hooijer. ''S. indonesicus'' was originally described by Miklós Kretzoi based on a molar found near Bumiayu, originally attributed to ''Elephas planifrons'', who coined the genus ''Stegoloxodon'' to contain the species. A 1973 paper argued for the synonymy of the two species,Maglio, V.J. (1973). ''Origin and evolution of the Elephantidae''. Transactions of the American Philosophical Society Philadelphia Volume 63. American Philosophical Society, Philadelphia. Pp. 149 which was later rejected, though they are usually considered closely related. Some later papers referred the species to ''Elephas''. A paper by Paul Yves Sondaar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Elephant
Dwarf elephants are prehistoric members of the order Proboscidea which, through the process of allopatric speciation on islands, evolved much smaller body sizes (around shoulder height) in comparison with their immediate ancestors. Dwarf elephants are an example of insular dwarfism, the phenomenon whereby large terrestrial vertebrates (usually mammals) that colonize islands evolve dwarf forms, a phenomenon attributed to adaptation to resource-poor environments and lack of predation and competition. Fossil remains of dwarf elephants have been found on the Mediterranean islands of Cyprus, Malta, Crete, Sicily, Sardinia, the Cyclades Islands and the Dodecanese Islands, which are mostly members of the genus ''Palaeoloxodon'', descending from the large tall straight-tusked elephant (''Palaeoloxodon antiquus'') of mainland Europe'','' though two species represent dwarf mammoths. Dwarf species of elephants and '' Stegodon'' have been found on the islands of Indonesia and the Philippi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elephas Planifrons
''Elephas planifrons'' is an extinct species of elephant, known from the Late Pliocene-Early Pleistocene of the Indian subcontinent and probably South East Asia (Java, Indonesia). Description The number of lamellae on the third molars is typically in the range of 11 to 15. Members of the species retained permanent premolars, unlike living Asian elephants. Ecology Isotopic evidence suggests that the species had a grazing based diet. Evolution ''Elephas planifrons'' represents one of the earliest dispersals of elephants outside of Africa, first arriving on the Indian subcontinent around 3.6 million years ago (though some authors have suggested a much earlier age over 5 million years ago). The date of the last record of the species is highly uncertain, with estimates ranging from 2.5 million to 800,000 years ago. While only definitively reported from the Indian subcontinent, possible ''E. planifrons'' remains have been reported from Indonesia, and the species may be closely relat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolars
The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth distal to the canines, preceded by deciduous molars. Morphology There is always one large buccal cusp, especially so in the mandibular first premolar. The lower seco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenozoic Mammals Of Asia
The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three geological eras of the Phanerozoic Eon, preceded by the Mesozoic and Paleozoic. The Cenozoic started with the Cretaceous–Paleogene extinction event, when many species, including the non-avian dinosaurs, became extinct in an event attributed by most experts to the impact of a large asteroid or other celestial body, the Chicxulub impactor. The Cenozoic is also known as the Age of Mammals because the terrestrial animals that dominated both hemispheres were mammalsthe eutherians (placentals) in the Northern Hemisphere and the metatherians (marsupials, now mainly restricted to Australia and to some extent South America) in the Southern Hemisphere. The extinction of many groups allowed mammals and birds to greatly diversify so that large mamma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene Extinctions
The Late Pleistocene to the beginning of the Holocene saw the extinction of the majority of the world's megafauna, typically defined as animal species having body masses over , which resulted in a collapse in faunal density and diversity across the globe. The extinctions during the Late Pleistocene are differentiated from previous extinctions by their extreme size bias towards large animals (with small animals being largely unaffected), and widespread absence of ecological succession to replace these extinct megafaunal species, and the regime shift of previously established faunal relationships and habitats as a consequence. The timing and severity of the extinctions varied by region and are generally thought to have been driven by humans, climatic change, or a combination of both. Human impact on megafauna populations is thought to have been driven by hunting ("overkill"), as well as possibly environmental alteration. The relative importance of human vs climatic factors in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Elephants
Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by the 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. It is based on an old conception of history that without written records there could be no history. The most common conception today is that history is based on evidence, however the concept of prehistory hasn't been completely discarded. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
