Citizendia

Rodents
Fossil range: Early Paleocene - Recent
Ammospermophilus leucurus
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Infraclass:Eutheria
Superorder:Euarchontoglires
Order:Rodentia
Bowdich, 1821
Suborders

Sciuromorpha
Castorimorpha
Myomorpha
Anomaluromorpha
Hystricomorpha

Rodentia is an order of mammals also known as rodents, characterised by two continuously-growing incisors in the upper and lower jaws which must be kept short by gnawing. The Paleocene or Palaeocene, "early dawn of the recent" is a geologic epoch that lasted from 65 The White-tailed Antelope Squirrel ( Ammospermophilus leucurus) is a diurnal species of Ground squirrel found in Arid regions of the southwestern Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals The Euarchontoglires (synonymous with Supraprimates) are a Mammalian superorder based on molecular genetic sequence analyses and Retrotransposon presence/absence Thomas Edward Bowdich ( 1790 - 10 January 1824) was an English traveller and Author. The term Sciuromorpha has referred to numerous groups of Rodents In fact the only family common to all variations is the Sciuridae, the squirrels Castorimorpha is the suborder of Rodents containing the Beavers the Pocket gophers and the kangaroo rats and mice. Suborder Myomorpha contains 1137 species of mouse-like Rodents nearly a quarter of all Mammal species Anomaluromorpha is the name given to a clade that unites the Anomalures with the Springhare. The term Hystricomorpha has had many definitions throughout its history This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Incisors (from Latin incidere, "to cut" are the first kind of Tooth in Heterodont Mammals They are located in the Premaxilla [1][2]

Forty percent of mammal species are rodents, and they are found in vast numbers on all continents other than Antarctica. Common rodents include mice, rats, squirrels, chipmunks, gophers, porcupines, beavers, hamsters, gerbils, guinea pigs and degus. A mouse (plural mice) is a small Animal that belongs to one Rats are various medium sized long-tailed Rodents of the superfamily Muroidea A squirrel is one of the many small or medium-sized Rodents in the family Sciuridae. Chipmunk is the common name for any small Squirrel -like Rodent species of the genus Tamias in the family Sciuridae. A gopher is a small burrowing Rodent that comes in many varieties including Pocket gophers of the family Geomyidae, native to Porcupines are Rodents with a coat of sharp spines or quills that defend them from predators Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe Hamsters are Rodents belonging to the Subfamily Cricetinae. The subfamily contains about 18 Species, classified in six or seven genera A gerbil is a small mammal of the order Rodentia Once known simply as " desert rats " the gerbil subfamily includes about 110 species of African The Guinea pig (also commonly called the cavy after its scientific name Cavia porcellus) is a species of Rodent belonging to the family Caviidae The Degu ( Octodon degus) is a small caviomorph Rodent that is native to Chile. [1] Rodents have sharp incisors that they use to gnaw wood, break into food, and bite predators. Most eat seeds or plants, though some have more varied diets. Some species have historically been pests, eating human seed stores and spreading disease.

Contents

Size and range of order

In terms of number of species — although not necessarily in terms of number of organisms (population) or biomass — rodents make up the largest order of mammals. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. Biomass, in Ecology, is the mass of living biological organisms in a given area or Ecosystem at a given time There are about 2,277 species of rodents (Wilson and Reeder, 2005), with over 40 percent of mammalian species belonging to the order. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. [3] Their success is probably due to their small size, short breeding cycle, and ability to gnaw and eat a wide variety of foods. (Lambert, 2000)

Rodents are found in vast numbers on all continents except Antarctica, most islands, and in all habitats except oceans. They are the only placental order, other than bats (Chiroptera) and Pinnipeds, to reach Australia without human introduction. See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals Pinnipeds ("fin-feet" lit "winged feet" or fin-footed mammals are a widely distributed and diverse group of semi-aquatic marine Mammals comprising For a topic outline on this subject see List of basic Australia topics.

Characteristics

The capybara, the largest living rodent, can weigh up to 65 kg.
The capybara, the largest living rodent, can weigh up to 65 kg. Capybara ( Hydrochoerus hydrochaeris) also known as capibara, chigüire in Venezuela chigüiro, carpincho

Many rodents are small; the tiny African pygmy mouse is only 6 cm in length and 7 grams in weight. The African Pygmy Mouse, ( Mus minutoides) is possibly the smallest of all Rodents and one of the smallest Mammals It is widespread within sub-Saharan On the other hand, the capybara can weigh up to 65 kg (140 lb), and the largest known rodent, the extinct Josephoartigasia monesi, is estimated to weigh about 1,000 kg (2,200 lb), and possibly up to 1,534 kg (3,380 lb)[4] or 2,586 kg (5,700 lb)[5]. Capybara ( Hydrochoerus hydrochaeris) also known as capibara, chigüire in Venezuela chigüiro, carpincho Josephoartigasia monesi is the largest known Rodent, and lived approximately 4 to 2 million years ago in South America during the Pliocene

Rodents have two incisors in the upper as well as in the lower jaw which grow continuously and must be kept worn down by gnawing; this is the origin of the name, from the Latin rodere, to gnaw, and dens, dentis, tooth. Incisors (from Latin incidere, "to cut" are the first kind of Tooth in Heterodont Mammals They are located in the Premaxilla The jaw is either of the two opposable structures forming or near the entrance to the Mouth. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. These teeth are used for cutting wood, biting through the skin of fruit, or for defense. The teeth have enamel on the outside and exposed dentine on the inside, so they self-sharpen during gnawing. Tooth enamel is the hardest and most highly mineralized substance of the body and with Dentin, Cementum, and dental pulp is one of the four major Dentin ( BE: dentine) is a calcified tissue of the body and along with enamel, Cementum, and pulp is one of the four Rodents lack canines, and have a space between their incisors and premolars. "Cuspid" redirects here For the heart valves see Bicuspid valve and Tricuspid valve. Incisors (from Latin incidere, "to cut" are the first kind of Tooth in Heterodont Mammals They are located in the Premaxilla Nearly all rodents feed on plants, seeds in particular, but there are a few exceptions which eat insects or fish. Some squirrels are known to eat passerine birds like cardinals and blue jays. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. The Cardinals or Cardinalidae are a family of Passerine Birds found in North and South America. The Blue Jay ( Cyanocitta cristata) is a Passerine bird and a member of the family Corvidae native to North America.

Typical rodent tooth system
Typical rodent tooth system

Rodents are important in many ecosystems because they reproduce rapidly, and can function as food sources for predators, mechanisms for seed dispersal, and as disease vectors. Biological dispersal refers to those processes by which a Species maintains ecosystem In Epidemiology, a vector is an Organism that does not cause Disease itself but which transmits Infection by conveying Pathogens from Humans use rodents as a source of fur, as pets, as model organisms in animal testing, for food, and even in detecting landmines. Fur is a body hair of any non-human Mammal, also known as the Pelage. A model organism is a Species that is extensively studied to understand particular biological Phenomena, with the expectation that discoveries made A land mine is an Explosive device designed to be placed on or in the ground to explode when triggered by an operator or the Proximity of a vehicle person [6]

Members of non-rodent orders such as Chiroptera (bats), Scandentia (treeshrews), Insectivora (moles, shrews and hedgehogs), Lagomorpha (hares, rabbits and pikas) and mustelid carnivores such as weasels and mink are sometimes confused with rodents. The treeshrews (or tree shrews) are small Mammals native to the tropical forests of Southeast Asia. The treeshrews (or tree shrews) are small Mammals native to the tropical forests of Southeast Asia. The order Insectivora (from Latin insectum "insect" and vorare "to eat" is a now-abandoned biological grouping within the A hedgehog is any of the small spiny Mammals of the Subfamily Erinaceinae and the order Erinaceomorpha. The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two families, the Leporidae ( Hares and Hares and jackrabbits are Leporids belonging to the Genus Lepus. Rabbits are small Mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world Pikas are small hamster-like animals with short limbs rounded ears and short tails Mustelidae or Mustelids (from Latin mustela, Weasel) commonly referred to as the weasel family, is a family of carnivorous Mammals A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting Weasels are Mammals in the genus Mustela of the Mustelidae family. There are two living species of " mink," the American Mink and the European Mink.

Evolution

Wood Mouse
Wood Mouse

The fossil record of rodent-like mammals begins shortly after the extinction of the non-avian dinosaurs 65 million years ago, as early as the Paleocene. The wood mouse ( Apodemus sylvaticus) also called the long-tailed field mouse, is a common Rodent that was recognised as a distinct species in 1894 FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. The Paleocene or Palaeocene, "early dawn of the recent" is a geologic epoch that lasted from 65 Some molecular clock data, however, suggests that modern rodents (members of the order Rodentia) already appeared in the late Cretaceous, although other molecular divergence estimations are in agreement with the fossil record. The molecular clock (based on the molecular clock hypothesis ( MCH) is a technique in Molecular evolution to relate the divergence time of two Species [7][8] By the end of the Eocene epoch, relatives of beavers, dormouse, squirrels, and other groups appeared in the fossil record. The Eocene epoch (558 ± 02 - 339 ± 01 Ma) is a major division of the Geologic timescale and the second epoch of the Palaeogene period in Dormice are Rodents of the family Gliridae. (This family is also variously called Myoxidae or Muscardinidae by different taxonomists They originated in Laurasia, the formerly joined continents of North America, Europe, and Asia. Laurasia (lɔˈreɪʃiə lɔˈreɪʒə was a Supercontinent that most recently existed as a part of the split of the Pangaean supercontinent in the late Mesozoic Some species colonized Africa, giving rise to the earliest hystricognaths. Anatomy Hystricognathi is an Infraorder of Rodents Hystricognaths are distinguished from other rodents by the Bone structure of their There is, however, a minority belief in the scientific community that evidence from mitochondrial DNA indicates that the Hystricognathi may belong to a different evolutionary offshoot and therefore a different order. Mitochondrial DNA ( mtDNA) is the DNA located in Organelles called mitochondria. eVolution is the third Album by eLDee, it was due to be released in 2008 From there hystricognaths rafted to South America, an isolated continent during the Oligocene and Miocene epochs. South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a A continent is one of several large Landmasses on Earth. They are generally identified by Convention rather than any strict criteria with seven regions The Oligocene is a geologic epoch of the Paleogene period and extends from about 33 The Miocene is a geological epoch of the Neogene period and extends from about 23 By the Miocene, Africa collided with Asia, allowing rodents such as the porcupine to spread into Eurasia. The Miocene is a geological epoch of the Neogene period and extends from about 23 Porcupines are Rodents with a coat of sharp spines or quills that defend them from predators For the superstate in George Orwell 's novel see Nations of Nineteen Eighty-Four. During the Pliocene, rodent fossils appeared in Australia. The Pliocene epoch (spelled Pleiocene in some older texts is the period in the Geologic timescale that extends Even though marsupials are the prominent mammals in Australia, rodents make up almost 25% of the mammals on the continent. Marsupials are an Infraclass of Mammals characterized by a distinctive pouch (called the marsupium) in which females carry their young through Meanwhile, the Americas became joined and some rodents expanded into new territory; mice headed south and porcupines headed north.

Some Prehistoric Rodents
Castoroides, a giant beaver
Ceratogaulus, a horned burrowing rodent
Spelaeomys, a rat that grew to a large size on the island of Flores
Giant hutias, a group of rodents once found in the West Indies
Ischyromys, a primitive squirrel-like rodent
Leithia, a giant dormouse
Neochoerus pinckneyi, a giant North American Capybara that weighed 50 kg
Josephoartigasia monesi, the largest known rodent
Phoberomys pattersoni, the second largest known rodent
Telicomys, a giant South American rodent

Classification

2/3 of rodent species are in the superfamily Muroidea. The families Muridae (blue) and Cricetidae (red) make up the bulk of the Muroidea.
2/3 of rodent species are in the superfamily Muroidea. Castoroides is an extinct genus of giant Beavers that lived in North America during the Pleistocene. Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe The horned gophers were several related Species of herbivorous Rodents from the Late Miocene and the earliest Pleistocene eras The Flores Cave Rat ( Spelaeomys florensis) lived on Flores Island, Indonesia. Flores is one of the Lesser Sunda Islands, an Island arc with an estimated area of 14300 km² extending east from the Java island of Indonesia The giant hutias are an Extinct group of large Rodents known from Fossil and Subfossil material in the West Indies The Caribbean (ˌkærəˡbiən kæ'rəbiən Cariben|Caraïben or Caraïben; Caraïbe or more commonly Antilles; Caribe is a Region consisting Ischyromys is an extinct genus of Rodent from North America. The 60 cm (2 ft long creature is one of the oldest rodents known A squirrel is one of the many small or medium-sized Rodents in the family Sciuridae. Dormice are Rodents of the family Gliridae. (This family is also variously called Myoxidae or Muscardinidae by different taxonomists Neochoerus pinckneyi ("Pinckney's New Hog" was a North American Species of Capybara. Capybara ( Hydrochoerus hydrochaeris) also known as capibara, chigüire in Venezuela chigüiro, carpincho Josephoartigasia monesi is the largest known Rodent, and lived approximately 4 to 2 million years ago in South America during the Pliocene Phoberomys pattersoni was a Rodent that lived in the ancient Orinoco River delta approximately 8 million years ago Telicomys is an extinct genus of Rodent from South America. With a length of more than 2 m (approx Muroidea is a large Superfamily of Rodents It includes Hamsters Gerbils true mice and Rats and many other relatives The families Muridae (blue) and Cricetidae (red) make up the bulk of the Muroidea. Muridae is the largest family of Mammals It contains over 600 species found naturally throughout Eurasia Africa and Australia The Cricetidae are a family of Rodents in the large and complex superfamily Muroidea.

Standard classification

The rodents are part of the clades: Glires (along with lagomorphs), Euarchontoglires (along with lagomorphs, primates, treeshrews, and colugos), and Boreoeutheria (along with most other placental mammals). A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor Glires (Latin glīrēs, Dormice) is a Clade consisting of Rodents and lagomorphs ( Rabbits Hares and Pikas The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two families, the Leporidae ( Hares and The Euarchontoglires (synonymous with Supraprimates) are a Mammalian superorder based on molecular genetic sequence analyses and Retrotransposon presence/absence The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two families, the Leporidae ( Hares and A primate is a member of the biological order Primates ( Latin: "prime first rank" the group that contains Lemurs the Aye-aye The treeshrews (or tree shrews) are small Mammals native to the tropical forests of Southeast Asia. Boreoeutheria (synonymous with Boreotheria) is a Clade that is composed of the sister Taxa Laurasiatheria and Euarchontoglires ( See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands The order Rodentia may be divided into suborders, infraorders, superfamilies and families. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Taxonomic rank ( rank, category, taxonomic category is an abstract term used in the Scientific classification, or Taxonomy, of organisms In Biological classification, family ( Latin

Classification scheme:

ORDER RODENTIA (from Latin, rodere, to gnaw)

Alternate classifications

The above taxonomy uses the shape of the lower jaw (sciurognath or hystricognath) as the primary character. Anomaluromorpha is the name given to a clade that unites the Anomalures with the Springhare. The Anomaluridae family is a family of Rodents found in central Africa The Springhare ( Pedetes capensis) or Springhaas, is not actually a Hare, but a member of the order Rodentia it is the only species in its Castorimorpha is the suborder of Rodents containing the Beavers the Pocket gophers and the kangaroo rats and mice. The family Castoridae contains the two living species of Beaver and their Fossil relatives The family Castoridae contains the two living species of Beaver and their Fossil relatives Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe Geomyoidea is a superfamily of Rodent that contains the pocket gophers ( Geomyidae) the kangaroo rats and mice ( Heteromyidae) and their Fossil The pocket gophers are burrowing Rodents of the family Geomyidae. The family of Rodents that include Kangaroo rats Kangaroo mice and rock pocket mice is the Heteromyidae family Kangaroo rats, genus Dipodomys, are small Rodents native to North America. A kangaroo mouse is either one of the two Species of jumping mouse ( Genus Microdipodops) native to the deserts of the Southwestern The term Hystricomorpha has had many definitions throughout its history Diatomyidae is a family of Hystricomorphous, Sciurognathous Rodents found in Asia. Gundis ( family Ctenodactylidae) are a group of small stocky Rodents found in Africa. Anatomy Hystricognathi is an Infraorder of Rodents Hystricognaths are distinguished from other rodents by the Bone structure of their The blesmols, also known as mole rats, or African mole-rats, are burrowing rodents of the family Bathyergidae. The Old World porcupines, or Hystricidae, are large terrestrial Rodents distinguished by the spiny covering from which they take their name The Dassie Rat, Petromus typicus, is an African Rodent found among rocky outcroppings The genus Thryonomys, also know as cane rats, grass cutters, or cutting grass, is a genus of Rodent found throughout Africa Caviomorpha is the Rodent Infraorder or Parvorder that unites all South American hystricognaths. The giant hutias are an Extinct group of large Rodents known from Fossil and Subfossil material in the West Indies Chinchilla rats are members of the family Abrocomidae. They resemble Chinchillas in appearance with a similar soft fur and silvery-grey color but have a body-structure Hutias are moderately large Cavy -like Rodents that inhabit the Caribbean Islands. The Cavy family ( Caviidae) is a family of Rodents native to South America, and including the domestic Guinea pig, wild cavies and The Guinea pig (also commonly called the cavy after its scientific name Cavia porcellus) is a species of Rodent belonging to the family Caviidae Capybara ( Hydrochoerus hydrochaeris) also known as capibara, chigüire in Venezuela chigüiro, carpincho The family Chinchillidae contains the Chinchillas Viscachas and their Fossil relatives Chinchillas are rabbit-sized Crepuscular Rodents native to the Andes mountains in South America. The tuco-tucos are members of a group of rodents that belong to the family Ctenomyidae. The tuco-tucos are members of a group of rodents that belong to the family Ctenomyidae. The Dasyproctidae are a family of large South American Rodents comprising the Agoutis and Acouchis Their fur is a reddish or dark colour above The family Dinomyidae was once a very successful group of South American Hystricognath Rodent, but now contains only a single living species the Pacarana UserPolbot. -->The Spiny Rat ( Rattus praetor) is a species of Rodent in the Muridae family The New World porcupines, or Erethizontidae, are large arboreal Rodents distinguished by the spiny covering from which they take their name The coypu, or nutria ( Myocastor coypus) is a large herbivorous, semiaquatic Rodent and the only member of the family Myocastoridae The Octodontidae are a family Rodents restricted to south-western South America. Suborder Myomorpha contains 1137 species of mouse-like Rodents nearly a quarter of all Mammal species Dipodoidea is a Superfamily of Rodents that includes Jumping mice and Jerboas The Dipodidae, or dipodids, are a family of Rodents found across the Northern hemisphere. Muroidea is a large Superfamily of Rodents It includes Hamsters Gerbils true mice and Rats and many other relatives Mouse-like hamsters are a group of small Rodents found in Syria, Azerbaijan, Iran, Turkmenistan, Afghanistan, and The Cricetidae are a family of Rodents in the large and complex superfamily Muroidea. Hamsters are Rodents belonging to the Subfamily Cricetinae. The subfamily contains about 18 Species, classified in six or seven genera The New World rats and mice are a group of related rodents found in North and South America. A vole is a small Rodent resembling a Mouse but with a stouter body a shorter hairy tail a slightly rounder head and smaller ears and eyes Muridae is the largest family of Mammals It contains over 600 species found naturally throughout Eurasia Africa and Australia A mouse (plural mice) is a small Animal that belongs to one Rats are various medium sized long-tailed Rodents of the superfamily Muroidea A gerbil is a small mammal of the order Rodentia Once known simply as " desert rats " the gerbil subfamily includes about 110 species of African The Maned Rat (or Crested Rat, as it is sometimes known ( Lophiomys imhausi) is a nocturnal long-haired and bushy-tailed East African Rodent Nesomyidae is a Family of African Rodents in the large and complex superfamily Muroidea. The Rodent family Platacanthomyidae, or Oriental Dormice, includes the spiny dormice and the Chinese pygmy dormice. The Spalacidae, or spalacids are a family of Rodents in the large and complex Superfamily Muroidea. Zokors are Asiatic burrowing Rodents resembling Mole rats They include two genera Myospalax and Eospalax. The term Sciuromorpha has referred to numerous groups of Rodents In fact the only family common to all variations is the Sciuridae, the squirrels The Mountain Beaver ( Aplodontia rufa) is a primitive Rodent unrelated to Beavers and not always found in Mountainous areas The Mountain Beaver ( Aplodontia rufa) is a primitive Rodent unrelated to Beavers and not always found in Mountainous areas Dormice are Rodents of the family Gliridae. (This family is also variously called Myoxidae or Muscardinidae by different taxonomists Dormice are Rodents of the family Gliridae. (This family is also variously called Myoxidae or Muscardinidae by different taxonomists The Sciurids or Squirrels are a large family of Rodents. The word Sciuridae means "shade-tail" and refers to the bushy appendage possessed A squirrel is one of the many small or medium-sized Rodents in the family Sciuridae. Chipmunk is the common name for any small Squirrel -like Rodent species of the genus Tamias in the family Sciuridae. The prairie dogs ( Cynomys) are small burrowing Rodents native to the Grasslands of North America Marmots are members of the Genus Marmota, in the Rodent family Sciuridae (squirrels Taxonomy is the practice and science of classification The word comes from the Greek, taxis (meaning 'order' 'arrangement' and, nomos The mandible (from Latin mandibula, "jawbone" or inferior maxillary bone forms the lower Jaw and holds the lower teeth in place Sciurognathi is a Suborder of Rodents that includes Squirrels Chipmunks Beavers and many types of mice. Anatomy Hystricognathi is an Infraorder of Rodents Hystricognaths are distinguished from other rodents by the Bone structure of their This is the most commonly used approach for dividing the order into suborders. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Taxonomic rank ( rank, category, taxonomic category is an abstract term used in the Scientific classification, or Taxonomy, of organisms Many older references emphasize the zygomasseteric system (suborders Protrogomorpha, Sciuromorpha, Hystricomorpha, and Myomorpha). The zygomasseteric system (or zygomasseteric structure) in Rodents is the anatomical arrangement of the Masseter muscle of the jaw and the Zygomatic The term Sciuromorpha has referred to numerous groups of Rodents In fact the only family common to all variations is the Sciuridae, the squirrels The term Hystricomorpha has had many definitions throughout its history Suborder Myomorpha contains 1137 species of mouse-like Rodents nearly a quarter of all Mammal species

Several molecular phylogenetic studies have used gene sequences to determine the relationships among rodents, but these studies are yet to produce a single consistent and well-supported taxonomy. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance Taxonomy is the practice and science of classification The word comes from the Greek, taxis (meaning 'order' 'arrangement' and, nomos Some clades have been consistently produced such as:

The positions of the Castoridae, Geomyoidea, Anomaluridae, and Pedetidae are still being debated. A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor The term Hystricomorpha has had many definitions throughout its history Gundis ( family Ctenodactylidae) are a group of small stocky Rodents found in Africa. Anatomy Hystricognathi is an Infraorder of Rodents Hystricognaths are distinguished from other rodents by the Bone structure of their The Old World porcupines, or Hystricidae, are large terrestrial Rodents distinguished by the spiny covering from which they take their name A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor The Rodent parvorder or infraorder Phiomorpha is comprised of several living and Extinct families found wholly or largely in Africa. Caviomorpha is the Rodent Infraorder or Parvorder that unites all South American hystricognaths. A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor Dormice are Rodents of the family Gliridae. (This family is also variously called Myoxidae or Muscardinidae by different taxonomists The term Sciuromorpha has referred to numerous groups of Rodents In fact the only family common to all variations is the Sciuridae, the squirrels The Mountain Beaver ( Aplodontia rufa) is a primitive Rodent unrelated to Beavers and not always found in Mountainous areas The Sciurids or Squirrels are a large family of Rodents. The word Sciuridae means "shade-tail" and refers to the bushy appendage possessed Suborder Myomorpha contains 1137 species of mouse-like Rodents nearly a quarter of all Mammal species Dipodoidea is a Superfamily of Rodents that includes Jumping mice and Jerboas Muroidea is a large Superfamily of Rodents It includes Hamsters Gerbils true mice and Rats and many other relatives The family Castoridae contains the two living species of Beaver and their Fossil relatives Geomyoidea is a superfamily of Rodent that contains the pocket gophers ( Geomyidae) the kangaroo rats and mice ( Heteromyidae) and their Fossil The Anomaluridae family is a family of Rodents found in central Africa The Springhare ( Pedetes capensis) or Springhaas, is not actually a Hare, but a member of the order Rodentia it is the only species in its

Monophyly or polyphyly?

In 1991, a paper submitted to Nature proposed that caviomorphs should be reclassified as a separate order (similar to Lagomorpha), based on an analysis of the amino acid sequences of guinea pigs. Nature is a prominent Scientific journal, first published on 4 November 1869 Caviomorpha is the Rodent Infraorder or Parvorder that unites all South American hystricognaths. The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two families, the Leporidae ( Hares and In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this The Guinea pig (also commonly called the cavy after its scientific name Cavia porcellus) is a species of Rodent belonging to the family Caviidae [9] This hypothesis was refined in a 1992 paper, which asserted the possibility that caviomorphs may have diverged from myomorphs prior to later divergences of Myomorpha; this would mean caviomorphs, or possibly hystricomorphs, would be moved out of the rodent classification into a separate order. Suborder Myomorpha contains 1137 species of mouse-like Rodents nearly a quarter of all Mammal species The term Hystricomorpha has had many definitions throughout its history [10] A minority scientific opinion briefly emerged arguing that guinea pigs, degus, and other caviomorphs are not rodents,[11][12] while several papers were put forward in support of rodent monophyly. The Guinea pig (also commonly called the cavy after its scientific name Cavia porcellus) is a species of Rodent belonging to the family Caviidae The Degu ( Octodon degus) is a small caviomorph Rodent that is native to Chile. A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor [13][14][15] Subsequent studies published since 2002, using wider taxon and gene samples, have restored consensus among mammalian biologists that the order Rodentia is monophyletic. A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance [16][17]

Notes

Links

References

  1. ^ a b rodent - Encyclopedia.com. Retrieved on 2007-11-03. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 644 - Umar ibn al-Khattab, the second Muslim Caliph, is killed by a Persian slave in Medina.
  2. ^ Rodents: Gnawing Animals. Retrieved on 2007-11-03. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 644 - Umar ibn al-Khattab, the second Muslim Caliph, is killed by a Persian slave in Medina.
  3. ^ Myers, Phil (2000). Rodentia. Animal Diversity Web. University of Michigan Museum of Zoology. Retrieved on 2006-05-25. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.
  4. ^ Millien, Virginie (05 2008). "The largest among the smallest: the body mass of the giant rodent Josephoartigasia monesi". Proceedings of the Royal Society B. doi:10.1098/rspb.2008.0087. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
  5. ^ Rinderknecht, Andrés; Blanco, R. Ernesto (01 2008). "The largest fossil rodent" (pdf). Proceedings of the Royal Society B: 923-928. doi:10.1098/rspb.2007.1645. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
  6. ^ Wines, Michael. "Gambian rodents risk death for bananas", The Age, The Age Company Ltd. , 2004-05-19. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1535 - French explorer Jacques Cartier sets sail on his second voyage to North America with three ships 110 men and Retrieved on 2006-05-25. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1085 - Alfonso VI of Castile takes Toledo Spain back from the Moors.   "A rat with a nose for landmines is doing its bit for humanity" Cited as coming from the New York Times in the article.
  7. ^ Douzery, E. J. P. , F. Delsuc, M. J. Stanhope, and D. Huchon (2003). "Local molecular clocks in three nuclear genes: divergence times for rodents and other mammals and incompatibility among fossil calibrations". Journal of Molecular Evolution 57: S201. doi:10.1007/s00239-003-0028-x. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
  8. ^ Horner, D. S. , K. Lefkimmiatis, A. Reyes, C. Gissi, C. Saccone, and G. Pesole (2007). "Phylogenetic analyses of complete mitochondrial genome sequences suggest a basal divergence of the enigmatic rodent Anomalurus". BMC Evolutionary Biology 7: 16. doi:10.1186/1471-2148-7-16. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
  9. ^ Graur, D. , Hide, W. and Li, W. (1991) 'Is the guinea-pig a rodent?' Nature, 351: 649-652.
  10. ^ Li, W. , Hide, W. , Zharkikh, A. , Ma, D. and Graur, D. (1992) 'The molecular taxonomy and evolution of the guinea pig. ' Journal of Heredity, 83 (3): 174-81.
  11. ^ D'Erchia, A. , Gissi, C. , Pesole, G. , Saccone, C. and Arnason, U. (1996) 'The guinea-pig is not a rodent. ' Nature, 381 (6583): 597-600.
  12. ^ Reyes, A. , Pesole, G. and Saccone, C. (2000) 'Long-branch attraction phenomenon and the impact of among-site rate variation on rodent phylogeny. ' Gene, 259 (1-2): 177-87.
  13. ^ Cao, Y. , Adachi, J. , Yano, T. and Hasegawa, M. (1994) 'Phylogenetic place of guinea pigs: No support of the rodent-polyphyly hypothesis from maximum-likelihood analyses of multiple protein sequences. ' Molecular Biology and Evolution, 11: 593-604.
  14. ^ Kuma, K. and Miyata, T. (1994) 'Mammalian phylogeny inferred from multiple protein data. ' Japanese Journal of Genetics, 69 (5): 555-66.
  15. ^ Robinson-Rechavi, M. , Ponger, L. and Mouchiroud, D. (2000) 'Nuclear gene LCAT supports rodent monophyly. ' Molecular Biology and Evolution, 17: 1410-1412.
  16. ^ Lin, Y-H, et al. "Four new mitochondrial genomes and the increased stability of evolutionary trees of mammals from improved taxon sampling. " Molecular Biology and Evolution 19 (2002): 2060-2070.
  17. ^ Carleton, Michael D. , and Musser, Guy G. "Order Rodentia". Mammal Species of the World, 3rd edition, 2005, vol. 2, p. 745. (Concise overview of the literature)

Dictionary

rodent

-noun

  1. A mammal of the order Rodentia, characterized by long incisors that grow continuously and are worn down by gnawing.
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