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Mammal Classification
Mammalia is a class of animal within the phylum Chordata. Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is universally accepted; McKenna & Bell (1997) and Wilson & Reader (2005) provide useful recent compendiums. Many earlier ideas from Linnaeus et al. have been completely abandoned by modern taxonomists, among these are the idea that bats are related to birds or that humans represent a group outside of other living things. Competing ideas about the relationships of mammal orders do persist and are currently in development. Most significantly in recent years, cladistic thinking has led to an effort to ensure that all taxonomic designations represent monophyletic groups. The field has also seen a recent surge in interest and modification due to the results of molecular phylogenetics. George Gaylord Simpson's classic "Principles of Classification and a Classification of Mammals" ( Simpson, 1945) ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal Species Pie Chart
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Monotremes And Marsupials
The class Mammalia (mammals) is divided into two subclasses based on reproductive techniques: egg-laying mammals (yinotherians or monotremes - see also Australosphenida), and mammals which give live birth (therians). The latter subclass is divided into two infraclasses: pouched mammals (metatherians or marsupials), and placental mammals (eutherians, for which see List of placental mammals). Classification updated from Wilson and Reeder's "Mammal Species of the World: A Taxonomic and Geographic Reference" using the "Planet Mammifères" website. Subclass Prototheria (the monotremes) Order Monotremata (monotremes, egg-laying mammals) *Family Ornithorhynchidae (platypus) **Genus ''Ornithorhynchus'' (platypus) ***Platypus (''Ornithorhynchus anatinus'') *Family Tachyglossidae (echidnas) ** Genus ''Tachyglossus'' (short-beaked echidna) ***Short-beaked echidna (''Tachyglossus aculeatus'') ** Genus ''Zaglossus'' (long-beaked echidnas) ***Western long-beaked echidna (''Zaglossus bruijnii ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamogalidae
Potamogalidae is the family of "otter shrews", a group of semiaquatic riverine afrotherian mammals indigenous to sub-Saharan Africa. They are most closely related to the tenrecs of Madagascar, from which they are thought to have split about 47–53 million years ago. They were formerly considered a subfamily of Tenrecidae. All otter shrews are carnivorous, preying on any aquatic animal they can find with their sensitive whiskers, particurally insects. As their common name suggests, they bear a strong, but superficial resemblance to true otters to which they are not closely related, nor are they closely related to true shrews. They move through the water by undulating their tail in a side-to-side motion similar to the motions made by a crocodile swimming. Morphology Otter shrews have small eyes and ears, consistent with the features of nearly all shrews. They have a broad, flat, muzzle that is substantially covered with sensetive whiskers and ends in a leathery pad. The margins o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afrosoricida
The order Afrosoricida (a Latin-Greek compound name which means "looking like African shrews") contains the golden moles of Southern Africa, the otter shrews of equatorial Africa and the tenrecs of Madagascar. These three families of small mammals have traditionally been considered to be a part of the order Insectivora, and were later included in Lipotyphla after Insectivora was abandoned as a wastebasket taxon, before Lipotyphla was also found to be polyphyletic. Naming Some biologists use Tenrecomorpha as the name for the tenrec-golden mole clade, but Gary Bronner and Paulina Jenkins argue that Afrosoricida is more appropriate, despite their misgivings about the similarity between the name "Afrosoricida" and the unrelated shrew subgenus ''Afrosorex''. However, ''Afrosorex'' Hutterer, 1986 is a synonym of ''Crocidura'' Wagler, 1832, eliminating any confusion. Hedges discussed at length the problems with using Tenrecomorpha and other proposed names for this clade of mammals other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afroinsectiphilia
The Afroinsectiphilia (African insectivores) is a clade that has been proposed based on the results of recent molecular phylogenetic studies. Many of the taxa within it were once regarded as part of the order Insectivora, but Insectivora is now considered to be polyphyletic and obsolete. This proposed classification is based on molecular studies only, and there is no morphological evidence for it. The golden moles, otter shrews and tenrecs are part of this clade. Some also regard the elephant shrews and aardvarks as part of it, although these two orders were traditionally seen as primitive ungulates. The sister group of the Afroinsectiphilia is the Paenungulata, which were also traditionally regarded as ungulates. If the clade of Afrotheria is genuine, then the Afroinsectiphilia are the closest relatives of the Pseudoungulata (here regarded as part of Afroinsectiphilia) and the Paenungulata. In a classification governed by morphological data, both the Pseudoungulata and Paenun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantogenata
Atlantogenata is a proposed clade of mammals containing the cohorts or superorders Xenarthra and Afrotheria. These groups originated and radiated in the South American and African continents, respectively, presumably in the Cretaceous. Together with Boreoeutheria, they make up Eutheria. The monophyly of this grouping was supported by some genetic evidence. Alternative hypotheses are that Boreoeutheria and Afrotheria combine to form Epitheria (as generally supported by anatomical and other physiological evidence) or that Boreoeutheria and Xenarthra combine to form Exafroplacentalia or Notolegia. Updated analysis of transposable element A transposable element (TE, transposon, or jumping gene) is a nucleic acid sequence in DNA that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size. Transp ... insertions around the time of divergence strongly supports the fourth hypothesis of a near-conco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutheria
Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials. Eutherians are distinguished from noneutherians by various phenotypic traits of the feet, ankles, jaws and teeth. All extant eutherians lack epipubic bones, which are present in all other living mammals (marsupials and monotremes). This allows for expansion of the abdomen during pregnancy. The oldest-known eutherian species is '' Juramaia sinensis'', dated at from the early Late Jurassic ( Oxfordian) of China. Eutheria was named in 1872 by Theodore Gill; in 1880 Thomas Henry Huxley defined it to encompass a more broadly defined group than Placentalia. Characteristics Distinguishing features are: *an enlarged malleolus ("little hammer") at the bottom of the tibia, the larger of the two shin bones *the joint between the first metatarsal bone and the entocuneiform bone (the innermost of the three cuneiform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boreotheria
Boreoeutheria (, "northern true beasts") is a magnorder of placental mammals that groups together superorders Euarchontoglires and Laurasiatheria. With a few exceptionsExceptional clades whose males lack the usual boreoeutherian scrotum are moles, hedgehogs, pangolins, some pinnipeds, rhinoceroses, tapirs, hippopotamuses, and cetaceans. male animals in the clade have a scrotum, an ancestral feature of the clade. The sub-clade Scrotifera was named after this feature. Etymology The name of this magnorder comes from Ancient Greek words: * () meaning ' north wind' or 'the North', * () meaning 'good', 'right', or 'true', * and () meaning 'beast'. Boreoeutherian ancestor The majority of earliest known fossils belonging to this group date to about 66 million years ago, shortly after the K-Pg extinction event, though molecular data suggest they may have originated earlier, during the Cretaceous period. This is further supported with fossils of '' Altacreodus magnus'' and two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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