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Marsupials
Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a relatively undeveloped state and then nurtured within a pouch on their mother's abdomen. Extant marsupials encompass many species, including kangaroos, koalas, opossums, possums, Tasmanian devils, wombats, wallabies, and bandicoots. Marsupials constitute a clade stemming from the last common ancestor of extant Metatheria, which encompasses all mammals more closely related to marsupials than to placentals. The evolutionary split between placentals and marsupials occurred 125-160 million years ago, in the Middle Jurassic-Early Cretaceous period. Presently, close to 70% of the 334 extant marsupial species are concentrated on the Australian continent, including mainland Australia, Tasmania, New Guinea, and nearby islands. The remaini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polydolopimorphia
Polydolopimorphia is an extinct order of metatherians, closely related to extant marsupials. Known from the Paleocene-Pliocene of South America and the Eocene of Antarctica, they were a diverse group during the Paleogene, filling many niches, before declining and becoming extinct at the end of the Neogene. It is divided into two suborders, Bonapartheriiformes, and Polydolopiformes Most members are only known from jaw fragments, which have their characteristically generally bunodont teeth. The morphology of their teeth has led to proposals that polydolopimorphians may be crown group marsupials, nested within Australidelphia, though this proposal, has been questioned, with other analyses finding them outside of crown-group Marsupialia. The monophyly of the group has been questioned, due to the possibility of the characteristic bunodont teeth emerging convergently in unrelated groups, rather than reflecting a true phylogenetic relationship. The group contained omnivorous, frugivorous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Opossum
Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America in the late Cenozoic. The Virginia opossum is the only species found in the United States and Canada. It is often simply referred to as an opossum; in North America, it is commonly referred to as a possum (; sometimes rendered as ''possum'' in written form to indicate the dropped "o"). The Australasian arboreal marsupials of suborder Phalangeriformes are also called possums because of their resemblance to opossums, but they belong to a different order. The opossum is typically a nonaggressive animal and almost never carries the virus that causes rabies. Etymology The word ''opossum'' is derived from the Powhatan language and was first recorde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three Evolution of mammalian auditory ossicles, middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors Genetic divergence, diverged in the Carboniferous Period over 300 million years ago. Around 6,640 Neontology#Extant taxon, extant species of mammals have been described and divided into 27 Order (biology), orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, Mole (animal), moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the Artiodactyl, even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including Felidae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |