Euarchontoglires is a clade and a superorder of mammals, the living members of which belong to one of the five following groups: rodents, treeshrews and primates. The Euarchontoglires clade is based on DNA sequence analyses and retrotransposon markers that combine the clades Glires and Euarchonta. So far, few if any distinctive anatomical features have been recognized that support Euarchontoglires, nor does any strong evidence from anatomy support alternative hypotheses. Although both Euarchontoglires and diprotodont marsupials are documented to possess a vermiform appendix, this feature evolved as a result of convergent evolution. Euarchontoglires is now recognized as one of the four major subclades within the clade Eutheria, it is discussed without a taxonomic rank but has been called a cohort, magnorder, or superorder. Relations among the four cohorts and the identity of the placental root remain controversial. Euarchontoglires split from the Laurasiatheria sister group about 85 to 95 million years ago, during the Cretaceous, developed in the Laurasian island group that would become Europe.
This hypothesis is supported by molecular evidence. The combined clade of Euarchontoglires and Laurasiatheria is recognized as Boreoeutheria; the hypothesized relationship among the Euarchontoglires is as follows: One study based on DNA analysis suggests that Scandentia and Primates are sister clades, but does not discuss the position of Dermoptera. Although it is known that Scandentia is one of the most basal Euarchontoglire clades, the exact phylogenetic position is not yet considered resolved, it may be a sister of Glires, Primatomorpha or Dermoptera or to all other Euarchontoglires; some recent studies place Scandentia as sister of the Glires. Whole-genome duplication took place in the ancestral Euarchontoglires
Eutheria is one of two mammalian clades with extant members that diverged in the Early Cretaceous or the Late Jurassic. Except for the Virginia opossum, from North America, a metatherian, all post-Miocene mammals indigenous to Europe, Africa and North America north of Mexico are eutherians. Extant eutherians, their last common ancestor, all extinct descendants of that ancestor are members of Placentalia. Eutherians are distinguished from noneutherians by various phenotypic traits of the feet, ankles and teeth. All extant eutherians lack epipubic bones; this allows for expansion of the abdomen during pregnancy. The oldest-known eutherian species is Juramaia sinensis, dated at 161 million years ago from the Jurassic in China. Eutheria was named in 1872 by Theodore Gill. Distinguishing features are: an enlarged malleolus at the bottom of the tibia, the larger of the two shin bones the joint between the first metatarsal bone and the entocuneiform bone in the foot is offset farther back than the joint between the second metatarsal and middle cuneiform bones—in metatherians these joints are level with each other various features of jaws and teeth Eutheria contains several extinct genera as well as larger groups, many with complicated taxonomic histories still not understood.
Members of the Adapisoriculidae and Leptictida have been placed within the out-dated placental group Insectivora, while Zhelestids have been considered primitive ungulates. However, more recent studies have suggested these enigmatic taxa represent stem group eutherians, more basal to Placentalia; the weakly favoured cladogram favours Boreoeuthearia as a basal Eutherian clade as sister to the Atlantogenata
Rodents are mammals of the order Rodentia, which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents, they are the most diversified mammalian order and live in a variety of terrestrial habitats, including human-made environments. Species can be fossorial, or semiaquatic. Well-known rodents include mice, squirrels, prairie dogs, chinchillas, beavers, guinea pigs, hamsters and capybaras. Other animals such as rabbits and pikas, whose incisors grow continually, were once included with them, but are now considered to be in a separate order, the Lagomorpha. Nonetheless and Lagomorpha are sister groups, sharing a most recent common ancestor and forming the clade of Glires. Most rodents are small animals with robust bodies, short limbs, long tails, they use their sharp incisors to gnaw food, excavate burrows, defend themselves. Most eat seeds or other plant material, they tend to be social animals and many species live in societies with complex ways of communicating with each other.
Mating among rodents can vary from monogamy, to polygyny, to promiscuity. Many have litters of altricial young, while others are precocial at birth; the rodent fossil record dates back to the Paleocene on the supercontinent of Laurasia. Rodents diversified in the Eocene, as they spread across continents, sometimes crossing oceans. Rodents reached both South America and Madagascar from Africa and were the only terrestrial placental mammals to reach and colonize Australia. Rodents have been used as food, for clothing, as pets, as laboratory animals in research; some species, in particular, the brown rat, the black rat, the house mouse, are serious pests and spoiling food stored by humans and spreading diseases. Accidentally introduced species of rodents are considered to be invasive and have caused the extinction of numerous species, such as island birds isolated from land-based predators; the distinguishing feature of the rodents is their pairs of continuously growing, razor-sharp, open-rooted incisors.
These incisors little enamel on the back. Because they do not stop growing, the animal must continue to wear them down so that they do not reach and pierce the skull; as the incisors grind against each other, the softer dentine on the rear of the teeth wears away, leaving the sharp enamel edge shaped like the blade of a chisel. Most species have up to 22 teeth with no canines or anterior premolars. A gap, or diastema, occurs between the cheek teeth in most species; this allows rodents to suck in their cheeks or lips to shield their mouth and throat from wood shavings and other inedible material, discarding this waste from the sides of their mouths. Chinchillas and guinea pigs have a high-fiber diet. In many species, the molars are large, intricately structured, cusped or ridged. Rodent molars are well equipped to grind food into small particles; the jaw musculature is strong. The lower jaw is pulled backwards during chewing. Rodent groups differ in the arrangement of the jaw muscles and associated skull structures, both from other mammals and amongst themselves.
The Sciuromorpha, such as the eastern grey squirrel, have a large deep masseter, making them efficient at biting with the incisors. The Myomorpha, such as the brown rat, have enlarged temporalis muscles, making them able to chew powerfully with their molars; the Hystricomorpha, such as the guinea pig, have larger superficial masseter muscles and smaller deep masseter muscles than rats or squirrels making them less efficient at biting with the incisors, but their enlarged internal pterygoid muscles may allow them to move the jaw further sideways when chewing. The cheek pouch is a specific morphological feature used for storing food and is evident in particular subgroups of rodents like kangaroo rats, hamsters and gophers which have two bags that may range from the mouth to the front of the shoulders. True mice and rats do not contain this structure but their cheeks are elastic due to a high degree of musculature and innervation in the region. While the largest species, the capybara, can weigh as much as 66 kg, most rodents weigh less than 100 g.
The smallest rodent is the Baluchistan pygmy jerboa, which averages only 4.4 cm in head and body length, with adult females weighing only 3.75 g. Rodents have wide-ranging morphologies, but have squat bodies and short limbs; the fore limbs have five digits, including an opposable thumb, while the hind limbs have three to five digits. The elbow gives the forearms great flexibility; the majority of species are plantigrade, walking on both the palms and soles of their feet, have claw-like nails. The nails of burrowing species tend to be long and strong, while arboreal rodents have shorter, sharper nails. Rodent species use a wide variety of methods of locomotion including quadrupedal walking, burrowing, bipedal hopping and gliding. Scaly-tailed squirrels and flying squirrels, although not related, can both glide from tree to tree using parachute-like membranes that stretch from the fore to the hind limbs; the agouti is antelope-like, being digitigrade and having hoof-like nails. The majority of rodents have tails, which can be of many shapes and siz
A chordate is an animal constituting the phylum Chordata. During some period of their life cycle, chordates possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, a post-anal tail: these five anatomical features define this phylum. Chordates are bilaterally symmetric; the Chordata and Ambulacraria together form the superphylum Deuterostomia. Chordates are divided into three subphyla: Vertebrata. There are extinct taxa such as the Vetulicolia. Hemichordata has been presented as a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. Of the more than 65,000 living species of chordates, about half are bony fish that are members of the superclass Osteichthyes. Chordate fossils have been found from as early as the Cambrian explosion, 541 million years ago. Cladistically, vertebrates - chordates with the notochord replaced by a vertebral column during development - are considered to be a subgroup of the clade Craniata, which consists of chordates with a skull.
The Craniata and Tunicata compose the clade Olfactores. Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following anatomical features: A notochord, a stiff rod of cartilage that extends along the inside of the body. Among the vertebrate sub-group of chordates the notochord develops into the spine, in wholly aquatic species this helps the animal to swim by flexing its tail. A dorsal neural tube. In fish and other vertebrates, this develops into the spinal cord, the main communications trunk of the nervous system. Pharyngeal slits; the pharynx is the part of the throat behind the mouth. In fish, the slits are modified to form gills, but in some other chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live. Post-anal tail. A muscular tail that extends backwards behind the anus. An endostyle; this is a groove in the ventral wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus.
It stores iodine, may be a precursor of the vertebrate thyroid gland. There are soft constraints that separate chordates from certain other biological lineages, but are not part of the formal definition: All chordates are deuterostomes; this means. All chordates are based on a bilateral body plan. All chordates are coelomates, have a fluid filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm; the following schema is from the third edition of Vertebrate Palaeontology. The invertebrate chordate classes are from Fishes of the World. While it is structured so as to reflect evolutionary relationships, it retains the traditional ranks used in Linnaean taxonomy. Phylum Chordata †Vetulicolia? Subphylum Cephalochordata – Class Leptocardii Clade Olfactores Subphylum Tunicata – Class Ascidiacea Class Thaliacea Class Appendicularia Class Sorberacea Subphylum Vertebrata Infraphylum incertae sedis Cyclostomata Superclass'Agnatha' paraphyletic Class Myxini Class Petromyzontida or Hyperoartia Class †Conodonta Class †Myllokunmingiida Class †Pteraspidomorphi Class †Thelodonti Class †Anaspida Class †Cephalaspidomorphi Infraphylum Gnathostomata Class †Placodermi Class Chondrichthyes Class †Acanthodii Superclass Osteichthyes Class Actinopterygii Class Sarcopterygii Superclass Tetrapoda Class Amphibia Class Sauropsida Class Synapsida Craniates, one of the three subdivisions of chordates, all have distinct skulls.
They include the hagfish. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or all deuterostomes, are by their tails". Most craniates are vertebrates; these consist of a series of bony or cartilaginous cylindrical vertebrae with neural arches that protect the spinal cord, with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, are therefore not regarded as vertebrates, but as members of the craniates, the group from which vertebrates are thought to have evolved; however the cladistic exclusion of hagfish from the vertebrates is controversial, as they ma
The water voles are large voles in the genus Arvicola. They are found in much of northern Asia. A water vole found in Western North America was considered a member of this genus, but has been shown to be more related to members of the genus Microtus. Head and body lengths are 12–22 cm, tail lengths are 6.5–12.5 cm, their weights are 70–250 g. The animals may exhibit indeterminate growth, they have hairy fringes on their feet that improve their swimming ability. European water vole Southwestern water vole Montane water vole Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London. Townsend, C. Begon, M. and Harper, J. L. 2003. Essentials of Ecology: second edition. Blackwell Publishing, Oxford
Arvicolini is a tribe of voles in the subfamily Arvicolinae. Tribe Arvicolini Genus Arvicola - water voles European water vole, Arvicola amphibius Southwestern water vole, Arvicola sapidus Montane water vole, Arvicola scherman Genus Blanfordimys Afghan vole, Blanfordimys afghanus Bucharian vole, Blanfordimys bucharicus Genus Chionomys - snow voles Caucasian snow vole, Chionomys gud European snow vole, Chionomys nivalis Robert's snow vole, Chionomys roberti Genus Lasiopodomys Brandt's vole, Lasiopodomys brandtii Plateau vole, Lasiopodomys fuscus Mandarin vole, Lasiopodomys mandarinus Genus Lemmiscus Sagebrush vole, Lemmiscus curtatus Genus Microtus - voles Insular vole, Microtus abbreviatus California vole, Microtus californicus Rock vole, Microtus chrotorrhinus Long-tailed vole, Microtus longicaudus Mexican vole, Microtus mexicanus Singing vole, Microtus miurus Water vole, Microtus richardsoni Zempoaltépec vole, Microtus umbrosus Taiga vole, Microtus xanthognathus Subgenus Microtus Field vole, Microtus agrestis Anatolian vole, Microtus anatolicus Common vole, Microtus arvalis Cabrera's vole, Microtus cabrerae Doğramaci's vole, Microtus dogramacii Günther's vole, Microtus guentheri Tien Shan vole, Microtus ilaeus Persian vole, Microtus irani Southern vole, Microtus levis Paradox vole, Microtus paradoxus Qazvin vole, Microtus qazvinensis Schidlovsky's vole, Microtus schidlovskii Social vole, Microtus socialis European pine vole, Microtus subterraneus Transcaspian vole, Microtus transcaspicus Subgenus Terricola Bavarian pine vole, Microtus bavaricus Calabria pine vole, Microtus brachycercus Daghestan pine vole, Microtus daghestanicus Mediterranean pine vole, Microtus duodecimcostatus Felten's vole, Microtus felteni Liechtenstein's pine vole, Microtus liechtensteini Lusitanian pine vole, Microtus lusitanicus Major's pine vole, Microtus majori Alpine pine vole, Microtus multiplex Savi's pine vole, Microtus savii Tatra pine vole, Microtus tatricus Thomas's pine vole, Microtus thomasi Subgenus Mynomes Beach vole, Microtus breweri Gray-tailed vole, Microtus canicaudus Montane vole, Microtus montanus Creeping vole, Microtus oregoni Meadow vole, Microtus pennsylvanicus Townsend's vole, Microtus townsendii Subgenus Alexandromys Clarke's vole, Microtus clarkei Evorsk vole, Microtus evoronensis Reed vole, Microtus fortis Gerbe's vole, Microtus gerbei Taiwan vole, Microtus kikuchii Lacustrine vole, Microtus limnophilus Maximowicz's vole, Microtus maximowiczii Middendorf's vole, Microtus middendorffi Mongolian vole, Microtus mongolicus Japanese grass vole, Microtus montebelli Muisk vole, Microtus mujanensis Tundra vole, Microtus oeconomus Sakhalin vole, Microtus sachalinensis Subgenus Stenocranius Narrow-headed vole, Microtus gregalis Subgenus Pitymys Guatemalan vole, Microtus guatemalensis Tarabundí vole, Microtus oaxacensis Woodland vole, Microtus pinetorum Jalapan pine vole, Microtus quasiater Subgenus Pedomys Prairie vole, Microtus ochrogaster Subgenus Hyrcanicola Schelkovnikov's pine vole, Microtus schelkovnikovi Genus Neodon - mountain voles Juniper vole, Neodon juldaschi Chinese scrub vole, Neodon irene Sikkim vole, Neodon sikimensis Forrest's mountain vole, Neodon forresti Genus Phaiomys Blyth's vole, Phaiomys leucurus Genus Proedromys Duke of Bedford's vole, Proedromys bedfordi Proedromys liangshanensis Genus Volemys Szechuan vole, Volemys millicens Marie's vole, Volemys musseri
Hebei is a province of China in the North China region. The modern province was established in 1911 as Chihli Province, its one-character abbreviation is "冀", named after Ji Province, a Han dynasty province that included what is now southern Hebei. The name Hebei means "north of the river", referring to its location to the north of the Yellow River; the modern province "Chili Province" was formed in 1911, when the central government dissolved the central governed area of "Chihli", which means "Directly Ruled" until it was renamed as "Hebei" in 1928. Beijing and Tianjin Municipalities, which border each other, were carved out of Hebei; the province borders Liaoning to the northeast, Inner Mongolia to the north, Shanxi to the west, Henan to the south, Shandong to the southeast. Bohai Bay of the Bohai Sea is to the east. A small part of Hebei, Sanhe Exclave, consisting of Sanhe, Dachang Hui Autonomous County, Xianghe County, an exclave disjointed from the rest of the province, is wedged between the municipalities of Beijing and Tianjin.
A common alternate name for Hebei is Yānzhào, after the state of Yan and state of Zhao that existed here during the Warring States period of early Chinese history. Plains in Hebei were the home of Peking man, a group of Homo erectus that lived in the area around 200,000 to 700,000 years ago. Neolithic findings at the prehistoric Beifudi site date back to 7000 and 8000 BC. During the Spring and Autumn period, Hebei was under the rule of the states of Yan in the north and Jin in the south. During this period, a nomadic people known as Dí invaded the plains of northern China and established Zhongshan in central Hebei. During the Warring States period, Jin was partitioned, much of its territory within Hebei went to Zhao; the Qin dynasty unified China in 221 BC. The Han dynasty ruled the area under two provinces, You Prefecture in the north and Ji Province in the south. At the end of the Han dynasty, most of Hebei came under the control of warlords Gongsun Zan in the north and Yuan Shao further south.
Hebei came under the rule of the Kingdom of Wei, established by the descendants of Cao Cao. After the invasions of northern nomadic peoples at the end of the Western Jin dynasty, the chaos of the Sixteen Kingdoms and the Northern and Southern dynasties ensued. Hebei in North China and right at the northern frontier, changed hands many times, being controlled at various points in history by the Later Zhao, Former Yan, Former Qin, Later Yan; the Northern Wei reunified northern China in 440, but split in half in 534, with Hebei coming under the eastern half, which had its capital at Ye, near modern Linzhang, Hebei. The Sui dynasty again unified China in 589. During the Tang dynasty, the area was formally designated "Hebei" for the first time. During the earlier part of the Five Dynasties and Ten Kingdoms period, Hebei was fragmented among several regimes, though it was unified by Li Cunxu, who established the Later Tang; the next dynasty, the Later Jin under Shi Jingtang, posthumously known as Emperor Gaozu of Later Jin, ceded much of modern-day northern Hebei to the Khitan Liao dynasty in the north.
During the Northern Song dynasty, the sixteen ceded prefectures continued to be an area of hot contention between Song China and the Liao dynasty. The Southern Song dynasty that came after abandoned all of North China, including Hebei, to the Jurchen Jin dynasty after the Jingkang Incident in 1127 of the Jin–Song wars; the Mongol Yuan dynasty did not establish Hebei as a province. Rather, the area was directly administrated by the Secretariat at capital Dadu; the Ming dynasty ruled Hebei as "Beizhili", meaning "Northern Directly Ruled", because the area contained and was directly ruled by the imperial capital, Beijing. When the Manchu Qing dynasty came to power in 1644, they abolished the southern counterpart, Hebei became known as "Zhili", or "Directly Ruled". During the Qing dynasty, the northern borders of Zhili extended deep into what is now Inner Mongolia, overlapped in jurisdiction with the leagues of Inner Mongolia; the Qing dynasty was replaced by the Republic of China. Within a few years, China descended with regional warlords vying for power.
Since Zhili was so close to Peking, the capital, it was the site of frequent wars, including the Zhiwan War, the First Zhifeng War and the Second Zhifeng War. With the success of the Northern Expedition, a successful campaign by the Kuomintang to end the rule of the warlords, the capital was moved from Peking to Nanking; as a result, the name of Zhili was changed to Hebei to reflect the fact that it had a standard provincial administration, that the capital had been relocated elsewhere. During the Second World War, Hebei was under the control of the Reorganized National Government of the Republic of Japan, a puppet state of Imperial Japan; the founding of the People's Republic of China saw several changes: the region around Chengde, previo