1.
Eocene
–
The Eocene Epoch, lasting from 56 to 33.9 million years ago, is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. As with other periods, the strata that define the start and end of the epoch are well identified. The name Eocene comes from the Ancient Greek ἠώς and καινός, the Eocene epoch is conventionally divided into early, middle, and late subdivisions. The corresponding rocks are referred to as lower, middle, the Ypresian stage constitutes the lower, the Priabonian stage the upper, and the Lutetian and Bartonian stages are united as the middle Eocene. The Eocene Epoch contained a variety of different climate conditions that includes the warmest climate in the Cenozoic Era. During this period of time, little to no ice was present on Earth with a difference in temperature from the equator to the poles. Following the maximum was a descent into an icehouse climate from the Eocene Optimum to the Eocene-Oligocene transition at 34 million years ago. During this decrease ice began to reappear at the poles, greenhouse gases, in particular carbon dioxide and methane, played a significant role during the Eocene in controlling the surface temperature. For the early Eocene there is discussion on how much carbon dioxide was in the atmosphere. This is due to numerous proxies representing different atmospheric carbon dioxide content, for contrast, today the carbon dioxide levels are at 400 ppm or 0. 04%. At about the beginning of the Eocene Epoch the amount of oxygen in the atmosphere more or less doubled. During the early Eocene, methane was another gas that had a drastic effect on the climate. In comparison to carbon dioxide, methane has much effect on temperature as methane is ~34 times more effective per molecule than carbon dioxide on a 100-year scale. Most of the methane released to the atmosphere during this period of time would have been from wetlands, swamps, the atmospheric methane concentration today is 0. 000179% or 1.79 ppmv. Due to the climate and sea level rise associated with the early Eocene, more wetlands, more forests. Comparing the early Eocene production of methane to current levels of atmospheric methane, biogenic production of methane produces carbon dioxide and water vapor along with the methane, as well as yielding infrared radiation
2.
Capybara
–
The capybara is the largest rodent in the world. It is a member of the genus Hydrochoerus, of which the other extant member is the lesser capybara. Close relatives are guinea pigs and rock cavies, and it is distantly related to the agouti, chinchillas. Native to South America, the capybara inhabits savannas and dense forests and it is a highly social species and can be found in groups as large as 100 individuals, but usually lives in groups of 10–20 individuals. The capybara is not a species and is hunted for its meat and hide. Its common name is derived from Tupi kaapiûara, a complex agglutination of kaá + píi + ú + ara, meaning one who eats slender leaves, the scientific name, both hydrochoerus and hydrochaeris, comes from Greek ὕδρω + χοίρος. The capybara and the lesser capybara belong to the subfamily Hydrochoerinae along with the rock cavies, the living capybaras and their extinct relatives were previously classified in their own family Hydrochoeridae. Since 2002, molecular studies have recognized a close relationship between Hydrochoerus and Kerodon supporting placement of both genera in a subfamily of Caviidae. The taxonomy of fossil hydrochoerines is also in a state of flux, in recent years, the diversity of fossil hydrochoerines has been substantially reduced. This is largely due to the recognition that capybara molar teeth show strong variation in shape over the life of an individual, the capybara has a heavy, barrel-shaped body and short head, with reddish-brown fur on the upper part of its body that turns yellowish-brown underneath. Its sweat glands can be found in the surface of the portions of its skin. The animal lacks under hair, and guard hair differs little from over hair. Adult capybaras grow to 106 to 134 cm in length, stand 50 to 62 cm tall at the withers, the top recorded weights are 91 kg for a wild female from Brazil and 73.5 kg for a wild male from Uruguay. Capybaras have slightly webbed feet and vestigial tails and their hind legs are slightly longer than their forelegs, they have three toes on their rear feet and four toes on their front feet. Their muzzles are blunt, with nostrils, and the eyes, females are slightly heavier than males. Its karyotype has 2n =66 and FN =102, capybaras are semiaquatic mammals found throughout almost all countries of South America except Chile. They live in forested areas near bodies of water, such as lakes, rivers, swamps, ponds. Capybara have flourished in cattle ranches and they roam in home ranges averaging 10 hectares in high-density populations
3.
Taxonomy (biology)
–
Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
4.
Animal
–
Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
5.
Chordate
–
Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
6.
Mammal
–
Mammals are any vertebrates within the class Mammalia, a clade of endothermic amniotes distinguished from reptiles by the possession of a neocortex, hair, three middle ear bones and mammary glands. All female mammals nurse their young with milk, secreted from the mammary glands, Mammals include the largest animals on the planet, the great whales. The basic body type is a quadruped, but some mammals are adapted for life at sea, in the air, in trees. The largest group of mammals, the placentals, have a placenta, Mammals range in size from the 30–40 mm bumblebee bat to the 30-meter blue whale. With the exception of the five species of monotreme, all modern mammals give birth to live young, most mammals, including the six most species-rich orders, belong to the placental group. The largest orders are the rodents, bats and Soricomorpha, the next three biggest orders, depending on the biological classification scheme used, are the Primates, the Cetartiodactyla, and the Carnivora. Living mammals are divided into the Yinotheria and Theriiformes There are around 5450 species of mammal, in some classifications, extant mammals are divided into two subclasses, the Prototheria, that is, the order Monotremata, and the Theria, or the infraclasses Metatheria and Eutheria. The marsupials constitute the group of the Metatheria, and include all living metatherians as well as many extinct ones. Much of the changes reflect the advances of cladistic analysis and molecular genetics, findings from molecular genetics, for example, have prompted adopting new groups, such as the Afrotheria, and abandoning traditional groups, such as the Insectivora. The mammals represent the only living Synapsida, which together with the Sauropsida form the Amniota clade, the early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period, this group diverged from the line that led to todays reptiles. Some mammals are intelligent, with some possessing large brains, self-awareness, Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent-marking, alarm signals, singing, and echolocation. Mammals can organize themselves into fission-fusion societies, harems, and hierarchies, most mammals are polygynous, but some can be monogamous or polyandrous. They provided, and continue to provide, power for transport and agriculture, as well as commodities such as meat, dairy products, wool. Mammals are hunted or raced for sport, and are used as model organisms in science, Mammals have been depicted in art since Palaeolithic times, and appear in literature, film, mythology, and religion. Defaunation of mammals is primarily driven by anthropogenic factors, such as poaching and habitat destruction, Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is accepted, McKenna & Bell and Wilson & Reader provide useful recent compendiums. Though field work gradually made Simpsons classification outdated, it remains the closest thing to a classification of mammals
7.
Rodent
–
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 species are rodents, they are found in vast numbers on all continents except Antarctica. They are the most diversified mammalian order and live in a variety of terrestrial habitats, Species can be arboreal, fossorial, or semiaquatic. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, hamsters, and capybaras. Other animals such as rabbits, hares, and pikas, whose incisors also grow continually, were included with them, but are now considered to be in a separate order. Nonetheless, Rodentia and Lagomorpha are sister groups, sharing a most recent common ancestor, most rodents are small animals with robust bodies, short limbs, and long tails. They use their incisors to gnaw food, excavate burrows. Most eat seeds or other plant material, but some have more varied diets and 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 underdeveloped, altricial young, while others are precocial at birth. The rodent fossil record back to the Paleocene on the supercontinent of Laurasia. Rodents greatly diversified in the Eocene, as spread across continents. Rodents reached both South America and Madagascar from Africa, and were the only placental mammals to reach. Rodents have been used as food, for clothing, as pets, some species, in particular the brown rat, the black rat, and the house mouse, are serious pests, eating and spoiling food stored by humans, and spreading diseases. The distinguishing feature of the rodents is their pairs of continuously growing and these incisors have thick layers of enamel on the front and 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, most species have up to 22 teeth with no canines or anterior premolars. A gap, or diastema, occurs between the incisors and the 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, chinchillas and guinea pigs have a high-fiber diet, their molars have no roots and grow continuously like their incisors
8.
Johann Friedrich von Brandt
–
Johann Friedrich von Brandt was a German naturalist, who worked mostly in Russia. Brandt was born in Jüterbog and educated at a gymnasium in Wittenberg, in 1831 he emigrated to Russia, and soon was appointed director of the Zoological Museum of the St Petersburg Academy of Sciences. Brandt encouraged the collection of animals, many of which were not represented in the museum. Many specimens began to arrive from the expeditions of Severtzov, Przhevalsky, Middendorff, Schrenck and he described several birds collected by Russian explorers off the Pacific Coast of North America, including Brandts cormorant, red-legged kittiwake and spectacled eider. As a paleontologist, Brandt ranks among the best and he was also an entomologist, specialising in Coleoptera and Diplopoda. He died in Merreküll, Governorate of Estonia and he is also commemorated in Brandts bat, Brandts hedgehog, three other species of mammals, and the lizard Iranolacerta brandtii. In addition, Johann Friedrich von Brandt concerned the continuation of the work Getreue Darstellung und Beschreibung der in der Arzneykunde gebräuchlichen Gewächse of Friedrich Gottlob Hayne, Getreue Darstellung und Beschreibung der in der Arzneykunde gebräuchlichen Gewächse wie auch solcher, welche mit ihnen verwechselt werden können. Band 2, Kryptogamen Hirschwald, Berlin 1838 Digital edition by the University, ztg.37743 Anonym 1879, Naturaliste Canad. Anz.2480 Medvedev, G. S.2000 Trudy Russk, ratzeburg, J. T. C.1874 Forstwissenschaftliches Schriftsteller-Lexikon. Berlin, Nicolaische Buchhandlung, X+1-516 72-76 Strauch, A.1889 Das zoologische Museum der Kaiserlichen Akademie der Wissenschaften zu St. Petersburg in seinem fünfzigjährigen Bestehen. Works by Johann Friedrich von Brandt at Project Gutenberg Works by or about Johann Friedrich von Brandt at Internet Archive Brandt J. F. scanned books, Brandt, Johann Friedrich in Complete Dictionary of Scientific Biography
9.
Dipodoidea
–
The Dipodidae, or dipodids, are a family of rodents found across the Northern Hemisphere, the sole family in the superfamily Dipodoidea. This family includes over 50 species among the 16 genera and they include the jerboas, jumping mice, and birch mice. Different species are found in grassland, deserts, and forests and they are all capable of saltation, a feature that is most highly evolved in the desert-dwelling jerboas. Dipodids are small to medium-sized rodents, ranging from 4 to 26 cm in body length and they are all adapted for jumping, although to varying degrees. The jerboas have very long legs which, in most species. They move either by jumping, or by walking on their hind legs, the jumping mice have long feet, but lack the extreme adaptations of the jerboas, so that they move by crawling or making short hops, rather than long leaps. Both jerboas and jumping mice have long tails to aid their balance, birch mice have shorter tails and feet, but they, too, move by jumping. Most dipodids are omnivorous, with a diet consisting of seeds, some species of jerboa, however, such as Allactaga sibirica, are almost entirely insectivorous. Like other rodents, they have gnawing incisors separated from the cheek teeth by a gap. The dental formula for dipodids is, Jerboas and birch mice make their nests in burrows, in contrast, while jumping mice sometimes co-opt the burrows of other species, they do not dig their own, and generally nest in thick vegetation. Most species hibernate for at least half the year, surviving on fat that they build up in the prior to going to sleep. Dipodids give birth to litters of two and seven young after a gestation period of between 17 and 42 days. They breed once or twice a year, depending on the species
10.
Zygomasseteric system
–
The zygomasseteric system in rodents is the anatomical arrangement of the masseter muscle of the jaw and the zygomatic arch of the skull. The anteroposterior or propalinal motion of the rodent jaw is enabled by an extension of the zygomatic arch, the main types are described as protrogomorphous, sciuromorphous, hystricomorphous, and myomorphous. This is the condition, found in the family Aplodontiidae. The rostrum is unmodified and the masseter originates on the ventral zygomatic surface, the Bathyergidae is considered secondarily protrogomorphous since its zygomatic condition clearly derived from a hystricomorphous ancestor. The ventral surface of the zygoma tilts and broadens into a zygomatic plate, the lateral masseter extends forwards onto the rostrum. The superficial masseter extends forwards along the zygoma and this condition is found in most of the family Sciuridae, and also in the Castoridae, the Eomyidae, and the Geomyoidea. The medial masseter is enlarged, and passes through an enlarged infraorbital foramen to originate on the side of the rostrum, the superficial masseter originates on the front edge of the zygoma, and the lateral masseter extends over most of its length. This condition is found throughout the suborders Hystricomorpha and Anomaluromorpha, in the suborder Myomorpha, it is found in the superfamily Dipodoidea and some fossil Muroidea. Hystricomorphy is also found in the African dormouse Graphiurus, which is a member of the suborder Sciuromorpha, a combination of the expanded and tilted zygoma of sciuromorphy and the enlarged foramen of hystricomorphy. This condition is found in the Muroidea and most Gliridae, korth & Emry 1991 suggest that the infraorbital foramen of the extinct sciurid subfamily Cedromurinae may have allowed for the passage of the masseter muscle. If true, this subfamily would represent an example of myomorphy in the rodent suborder Sciuromorpha. Bell, Sean D. Aplodontid, Scuirid, Castorid, Zapodid and Geomyoid rodents of the Rodent Hill locality, Cypress Hills Formation, Southwest Saskatchewan, Master of Science thesis, korth, William W. Emry, Robert J. The skull of Cedromus and a review of the Cedromurinae
11.
Hystricognathi
–
The Hystricognathi are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls. The masseter medialis passes partially through the foramen and connects to the bone on the opposite side. This, together with their lack of a plate and the relative size of the infraorbital foramen. The 18 families within the Hystricognathi are divided into two infraorders, the Phiomorpha and the Caviomorpha, the Caviomorpha are mostly native to South America, with a few species in North America, while the Phiomorpha occur in the Old World. Play behavior has been observed in seven hystricognath families, the caviomorphs chase each other, play-wrestle, and gallop. The longer-legged species chase more often than the shorter-legged species and they also rotate their heads and body muscles as a form of play
12.
Ctenodactylidae
–
Gundis or comb rats are a group of small, stocky rodents found in Africa. They live in rocky deserts across the northern parts of the continent, the family comprises four living genera and five species, as well as numerous extinct genera and species. They are in the superfamily Ctenodactyloidea and they first came to the notice of western naturalists in Tripoli in 1774, and were given the name gundi mice. Gundis are from 17–18 cm in length, with compact bodies covered in soft fur, short legs. They have only four toes on all feet and the toes of the hind feet carry comb-like bristles. Gundis have short tails, which in species are covered in a large fan of hair that aids in balancing as they move about their rocky. They are herbivorous, eating almost every type of available plant, like many other desert animals, they do not drink, obtaining all the moisture they need from their food. Because of the need to preserve moisture, female gundis produce only an amount of milk. Gundis live in colonies of up to a hundred or more individuals and they do not make permanent dens, but simply shelter in crevices in the rocks at night, or during midday when the sun becomes too hot for them to remain active. They are vocal animals, with a range of alarm calls, according to a DNA sequence study, the ancestors of the gundis diverged from those of the Laotian rock rat around the Lutetian, some 44 million years ago
13.
Anomaluridae
–
The Anomaluridae are a family of rodents found in central Africa. They are known as anomalures or scaly-tailed squirrels, the seven extant species are classified into three genera. They are distinguished by two rows of pointed, raised scales on the undersides of their tails, the anatomy of their heads is quite different from that of the sciurid flying squirrels. Most anomalurid species roost during the day in trees, with up to several dozen animals per tree. They are primarily herbivorous, and may travel up to 6 km from their tree in search of leaves, flowers, or fruit. They give birth to litters up to three young, which are born already furred and active, anomalurids represent one of several independent evolutions of gliding ability in mammals. The others include the flying squirrels of Eurasia and North America, colugos or flying lemurs of Southeast Asia. Pp. 1532–1534 in Mammal Species of the World a Taxonomic and Geographic Reference, D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore
14.
Pedetidae
–
The Pedetidae are a family of mammals from the rodent order. The two living species, the springhares, are distributed throughout much of southern Africa and also around Kenya, Tanzania, fossils have been found as far north as Turkey. Together with the anomalures, Pedetidae forms the suborder Anomaluromorpha, the fossil genus Parapedetes is also related. The family includes one living genus and three extinct genera, the Asian fossil Diatomys was previously included, but is now classified in the family Diatomyidae with the Laotian rock rat. Postcranial morphology and springing adaptations in Pedetidae from Arrisdrift, Middle Miocene, pelvic shape in gliding rodents, implications for the launch. Tracking genome organization in rodents by Zoo-FISH, drickamer, S. H. Vessey, and J. F. Merritt. Pp. 267-288 in Anderson, S. and J. K. Jones, orders and Families of Recent Mammals of the World. John Wiley and Sons, N. Y. xii+686 pp. Paradiso, walkers Mammals of the World, Third Edition. Savage, R. J. G. and M. R. Long, facts of File Publications, New York. 259 pp. Vaughan, T. A.1986, vii+576 pp. Vaughan, T. A. J. M. Ryan, N. J. Czaplewski. Wilson, D. E. and D. M. Reeder, mammal Species of the World, A Taxonomic and Geographic Reference
15.
Anomaluromorpha
–
Anomaluromorpha is the name given to a clade that unites the anomalures with the springhares. It has alternately been designated as either a suborder or infraorder, most recently, Carleton & Musser 2005 recognized it as one of five suborders of rodents. The suborder Anomaluromorpha was erected to unite sciurognathous rodents with a hystricomorphous zygomasseteric system restricted to sub-Saharan Africa, many authors have suggested that the two extant families may be only distantly related, and that they belong to separate suborders or infraorders. For example, the Pedetidae are the family of rodents with multiserial enamel except for the Hystricognathi. Montgelard et al.2002 generated some support for Anomaluromorpha in a molecular phylogeny using 12S rRNA, the suborder Anomaluromorpha contains nine living species in four genera and two families. An additional fossil family probably belongs to this group, †Parapedetidae Pedetidae - springhare Anomaluridae - scaly-tailed flying squirrels, flying mice The following fossil taxa are also sometimes placed in the Anomaluromorpha, †Diatomys †Zegdoumyidae
16.
Gundi
–
Gundis or comb rats are a group of small, stocky rodents found in Africa. They live in rocky deserts across the northern parts of the continent, the family comprises four living genera and five species, as well as numerous extinct genera and species. They are in the superfamily Ctenodactyloidea and they first came to the notice of western naturalists in Tripoli in 1774, and were given the name gundi mice. Gundis are from 17–18 cm in length, with compact bodies covered in soft fur, short legs. They have only four toes on all feet and the toes of the hind feet carry comb-like bristles. Gundis have short tails, which in species are covered in a large fan of hair that aids in balancing as they move about their rocky. They are herbivorous, eating almost every type of available plant, like many other desert animals, they do not drink, obtaining all the moisture they need from their food. Because of the need to preserve moisture, female gundis produce only an amount of milk. Gundis live in colonies of up to a hundred or more individuals and they do not make permanent dens, but simply shelter in crevices in the rocks at night, or during midday when the sun becomes too hot for them to remain active. They are vocal animals, with a range of alarm calls, according to a DNA sequence study, the ancestors of the gundis diverged from those of the Laotian rock rat around the Lutetian, some 44 million years ago
17.
Morphology (biology)
–
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the appearance, i. e. external morphology, as well as the form and structure of the internal parts like bones and organs. This is in contrast to physiology, which deals primarily with function, Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. The word morphology is from the Ancient Greek don, morphé, meaning form, among other important theorists of morphology are Lorenz Oken, Georges Cuvier, Étienne Geoffroy Saint-Hilaire, Richard Owen, Karl Gegenbaur and Ernst Haeckel. In English-speaking countries, the term molecular morphology has been used for time for describing the structure of compound molecules, such as polymers. Comparative Morphology is analysis of the patterns of the locus of structures within the plan of an organism. Functional Morphology is the study of the relationship between the structure and function of morphological features, experimental Morphology is the study of the effects of external factors upon the morphology of organisms under experimental conditions, such as the effect of genetic mutation. Anatomy is a branch of morphology that deals with the structure of organisms, most taxa differ morphologically from other taxa. Typically, closely related taxa differ much less than more distantly related ones, cryptic species are species which look very similar, or perhaps even outwardly identical, but are reproductively isolated. Conversely, sometimes unrelated taxa acquire a similar appearance as a result of convergent evolution or even mimicry, in addition, there can be morphological differences within a species, such as in Apoica flavissima where queens are significantly smaller than workers. A further problem with relying on morphological data is that what may appear, morphologically speaking, the significance of these differences can be examined through the use of allometric engineering in which one or both species are manipulated to phenocopy the other species. Invention and development of microscopy enable the observation of 3-D cell morphology with both spatial and temporal resolution. The dynamic processes of cell morphology which are controlled by a complex system play an important role in varied important biological process, such as immune. Comparative anatomy Insect morphology Morphometrics Neuromorphology Phenetics Phenotype Phenotypic plasticity Plant morphology
18.
Sciurognathi
–
Sciurognathi is a suborder of rodents that includes squirrels, chipmunks, beavers, and many types of mice. The group is characterized by a shape to the lower jaw. In sciurognaths, the process of the jaw is in the same plane as the root of the incisors. This is in contrast to the suborder Hystricognathi where the process is outside the plane formed at the root of the incisor due to the presence of a shelf for muscle attachment. The sciurognathous condition is considered to be the condition in rodents. Although hystricognaths are almost universally accepted as representing a real evolutionary grouping, in particular, gundis are thought to be more closely related to the hystricognathous rodents than to other sciurognaths. In spite of this, most texts continue to use these two suborders due primarily to a lack of a viable alternative, alternatively, some texts group rodents into three suborders on the basis of the shape of the infraorbital canal. According to this taxonomy the rodents are divided into the suborders Sciuromorpha, Hystricomorpha, and Myomorpha
19.
Paraphyletic
–
In taxonomy, a group is paraphyletic if it consists of the groups last common ancestor and all descendants of that ancestor excluding a few—typically only one or two—monophyletic subgroups. The group is said to be paraphyletic with respect to the excluded subgroups, the term is commonly used in phylogenetics and in linguistics. The term was coined to apply to well-known taxa like reptiles which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles and all descendants of that all extant reptiles as well as the extinct synapsids—except for mammals. Other commonly recognized paraphyletic groups include fish, monkeys and lizards, if many subgroups are missing from the named group, it is said to be polyparaphyletic. A paraphyletic group cannot be a clade, which is a monophyletic group, groups that include all the descendants of a common ancestor are said to be monophyletic. A paraphyletic group is a group from which one or more subsidiary clades is excluded to form a separate group. Ereshefsky has argued that paraphyletic taxa are the result of anagenesis in the group or groups. For example, dinosaurs are paraphyletic with respect to birds because birds possess many features that dinosaurs lack, a group whose identifying features evolved convergently in two or more lineages is polyphyletic. More broadly, any taxon that is not paraphyletic or monophyletic can be called polyphyletic and these terms were developed during the debates of the 1960s and 70s accompanying the rise of cladistics. The prokaryotes, because they exclude the eukaryotes, a descendant group, bacteria and Archaea are prokaryotes, but archaea and eukaryotes share a common ancestor that is not ancestral to the bacteria. The prokaryote/eukaryote distinction was proposed by Edouard Chatton in 1937 and was accepted after being adopted by Roger Stanier. The botanical code abandoned consideration of bacterial nomenclature in 1975, currently, dicotyledons are paraphyletic because the group excludes monocotyledons. Dicotyledon has not been used as an ICBN classification for decades, phylogenetic analysis indicates that the monocots are a development from a dicot ancestor. Excluding monocots from the dicots makes the latter a paraphyletic group, the order Artiodactyla, because it excludes Cetaceans. In the ICZN Code, the two taxa are orders of equal rank, molecular studies, however, have shown that the Cetacea descend from the Artiodactyl ancestors, although the precise phylogeny within the order remains uncertain. Without the Cetacean descendants the Artiodactyls must be paraphyletic, the class Reptilia as traditionally defined, because it excludes birds and mammals. In the ICZN Code, the three taxa are classes of equal rank, however, mammals hail from the synapsids and birds are descended from the dinosaurs, both of which are reptiles
20.
Caviomorpha
–
Caviomorpha is the rodent infraorder or parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence, the Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now accepted as a genuine part of the rodents. By the late Oligocene, all superfamilies and most families of caviomorphs are present in the fossil record, during this time, South America was isolated from all other continents. Several hypotheses have proposed as to how hystricognath rodents colonized this island continent. Most require that a group of these rodents traveled across ocean bodies atop a raft of mangroves or driftwood. The most common hypothesis suggests that the ancestor to all modern caviomorphs rafted across the Atlantic Ocean from Africa and this is supported by molecular results, which suggest that the Phiomorpha are sister taxa to the Caviomorpha. In fact, until the discovery of the Laotian rock rat, all modern hystricognath families were restricted to South America, Africa, the principal alternative hypothesis is that the caviomorph ancestor arose in Asia and migrated to South America through another continent. Fossil evidence suggests the Entodacrya may have originated in Asia and this is cited as evidence for an Asian origin for Caviomorpha as well. Likewise, Jenkins et al. argue that their discovery of a rodent family exclusive to Asia may be further evidence for an Asian origin of caviomorphs. Alternatively, the caviomorphs may have originated in Asia, but traveled through Africa, Australia and Antarctica, alternatively they may have originated in Africa and traveled to South America via Antarctica. New World monkeys appear to have colonized South America from Africa at a similar time, caviomorphs went on to colonize the West Indies as far as the Bahamas, reaching the Greater Antilles by the early Oligocene. This is commonly viewed as another example of oceanic dispersal, although a role for a land bridge has also been considered. Caviomorph rodents underwent an explosive diversification upon arrival into South America and they managed to outcompete other animals in rodent-like niches such as certain South American marsupials. Retaining predominantly herbivorous diets, they expanded their sizes to encompass a range from rat-sized echimyids to the bison-sized Phoberomys, habitats range from grasslands, high mountains, forest edges and dense tropical forests. The nutria has been introduced into North America and has proven a successful invasive species there. The Dinomyidae may belong to the Chinchilloidea, the Abrocomidae may belong to the Octodontoidea, huchon, D. E. J. P. Douzery. From the Old World to the New World, A molecular chronicle of the phylogeny, Jenkins, P. D. C. W. Kilpatrick, M. F. Robinson, and R. J. Timmins. Morphological and molecular investigations of a new family, genus and species of rodent from Lao PDR, la systématique des rongeurs hystricomorphes et la dérive des continents
21.
Monophyly
–
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it consists of an ancestral species and all its descendants. The term is synonymous with the uncommon term holophyly, monophyletic groups are typically characterized by shared derived characteristics. Monophyly is contrasted with paraphyly and polyphyly, as shown in the second diagram, a paraphyletic group consists of all of the descendants of a common ancestor minus one or more monophyletic groups. These definitions have taken time to be accepted. When the cladistic school of thought became mainstream in the 1960s, indeed, taxonomists sometimes used terms without defining them, leading to confusion in the early literature, a confusion which persists. On the broadest scale, definitions fall into two groups, willi Hennig defined monophyly as groups based on synapomorphy. Some authors have sought to define monophyly to include paraphyly as any two or more groups sharing a common ancestor, however, this broader definition encompasses both monophyletic and paraphyletic groups as defined above. Therefore, most scientists today restrict the term monophyletic to refer to groups consisting of all the descendants of one common ancestor, however, when considering taxonomic groups such as genera and species, the most appropriate nature of their common ancestor is unclear. Assuming that it would be one individual or mating pair is unrealistic for sexually reproducing species, some argue that using a broader definition, such as a species and all its descendants, does not really work to define a genus. According to D. M. Glossary of scientific naming Clade Paraphyly Polyphyly Crown group Abbey, graphical explanation of basic phylogenetic terms. Carr, Steven M. Concepts of monophyly, polyphyly & paraphyly
22.
Polyphyly
–
A polyphyletic group is characterized by one or more homoplasies, phenotypes which have converged or reverted so as to appear to be the same but which have not been inherited from common ancestors. Alternatively, polyphyletic is used to describe multiple ancestral sources regardless of convergence, for example, warm-bloodedness evolved separately in the ancestors of mammals and the ancestors of birds. Other polyphyletic groups are protozoans, lipotyphla, and algae, as well as invertebrates, many biologists aim to avoid homoplasies in grouping species together and therefore it is frequently a goal to eliminate groups that are found to be polyphyletic. This is often the stimulus for major revisions of the classification schemes, in many schools of taxonomy, the existence of polyphyletic groups in a classification is discouraged. Monophyletic groups are considered by these schools of thought to be the most important grouping of organisms, on the other hand, polyphyletic groups can often be delimited in terms of clades, for example the flying vertebrates consist of the bat, bird, and pterosaur clades. Because polyphyletic groups can frequently be defined as a sum of clades, a stronger reason is that grouping species monophyletically facilitates prediction far more than does polyphyletic grouping. Predictive success is the touchstone by which theories are evaluated in all experimental sciences, species have a special status in systematics as being an observable feature of nature itself and as the basic unit of classification. It is usually assumed that species are monophyletic. However hybrid speciation arguably leads to polyphyletic species, hybrid species are a common phenomenon in nature, particularly in plants where polyploidy allows for rapid speciation. Funk, D. J. and Omland, K. E. Species-level paraphyly and polyphyly, Frequency, cause and consequences, with insights from animal mitochondrial DNA Annu
23.
Long branch attraction
–
In phylogenetics, long branch attraction is a form of systematic error whereby distantly related lineages are incorrectly inferred to be closely related. Such bias is more common when the overall divergence of some results in long branches within a phylogeny. Long-branches are often attracted to the base of a phylogenetic tree, the frequency of true LBA is unclear and often debated. Although often viewed as a failing of parsimony-based methodology, LBA can result from a variety of scenarios, often this is because convergent evolution of one or more characters included in the analysis has occurred in multiple taxa. Although they were derived independently, these traits can be misinterpreted in the analysis as being shared due to common ancestry. A phylogenetic analysis will group these together as a clade unless other synapomorphies outweigh the homoplastic features to group together true sister taxa. The result of LBA in evolutionary analyses is that rapidly evolving lineages may be inferred to be closely related, for example, in DNA sequence-based analyses, the problem arises when sequences from two lineages evolve rapidly. There are only four possible nucleotides and when DNA substitution rates are high, when this happens, parsimony may erroneously interpret this homoplasy as a synapomorphy. The opposite effect may also be observed, in that if two branches exhibit particularly slow evolution among a wider, fast evolving group, those branches may be misinterpreted as closely related, as such, long branch attraction can in some ways be better expressed as branch length attraction. However, it is typically long branches that exhibit attraction, the recognition of long-branch attraction implies that there is some other evidence that suggests that the phylogeny is incorrect. For example, morphological data may suggest that taxa marked as closely related are not truly sister taxa, hennigs Auxiliary Principle suggests that synapomorphies should be viewed as de facto evidence of grouping unless there is specific contrary evidence. A simple and effective method for determining whether or not long branch attraction is affecting tree topology is the SAW method, named for Siddal, if long branch attraction is suspected in a pair of taxa, simply remove taxon A and re-run the analysis. Then remove A and replace B, running the analysis again, if either of the taxa appear at different branch points in the absence of the other, there is evidence of long branch attraction. Since long branches cant possibly attract one another when one is in the analysis. Assume for simplicity that we are considering a single binary character, because the distance from B to D is small, in the vast majority of all cases, B and D will be the same. Here, we assume that they are both +. If this is the case, there are four remaining possibilities, a and C can both be +, in which case all taxa are the same and all the trees have the same length. A can be + and C can be -, in which only one character is different
24.
South America
–
South America is a continent located in the western hemisphere, mostly in the southern hemisphere, with a relatively small portion in the northern hemisphere. It may also be considered a subcontinent of the Americas, which is the used in nations that speak Romance languages. The reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean, North America and it includes twelve sovereign states, a part of France, and a non-sovereign area. In addition to this, the ABC islands of the Kingdom of the Netherlands, Trinidad and Tobago, South America has an area of 17,840,000 square kilometers. Its population as of 2005 has been estimated at more than 371,090,000, South America ranks fourth in area and fifth in population. Brazil is by far the most populous South American country, with more than half of the population, followed by Colombia, Argentina, Venezuela. In recent decades Brazil has also concentrated half of the regions GDP and has become a first regional power, most of the population lives near the continents western or eastern coasts while the interior and the far south are sparsely populated. Most of the continent lies in the tropics, the continents cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the majority of South Americans speak Portuguese or Spanish. South America occupies the portion of the Americas. The continent is delimited on the northwest by the Darién watershed along the Colombia–Panama border. Almost all of mainland South America sits on the South American Plate, South Americas major mineral resources are gold, silver, copper, iron ore, tin, and petroleum. These resources found in South America have brought high income to its countries especially in times of war or of rapid growth by industrialized countries elsewhere. However, the concentration in producing one major export commodity often has hindered the development of diversified economies and this is leading to efforts to diversify production to drive away from staying as economies dedicated to one major export. South America is one of the most biodiverse continents on earth, South America is home to many interesting and unique species of animals including the llama, anaconda, piranha, jaguar, vicuña, and tapir. The Amazon rainforests possess high biodiversity, containing a proportion of the Earths species. Brazil is the largest country in South America, encompassing around half of the land area
25.
Metatheria
–
Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. Metatherians are one of three classes of extant mammals, monotremes, metatheria, and the eutherians consisting of twenty-one orders. Metatherians belong to a subgroup of the northern tribosphenic mammal clade or Boreosphenida and they differ from all other mammals in certain morphologies like their dental formula, which includes about five upper and four lower incisors, a canine, three premolars, and four molars. Other morphologies include skeletal and anterior dentition, such as wrist and ankle apomorphies, all metatherians share derived pedal characters, below is a metatherian cladogram from Wilson et al. Below is a listing of metatherians that do not fall readily into well-defined groups, around the end of the Triassic period, a Therapsid developed traits or characters that are diagnostic of the class Mammalia. This class gave rise to Multituberculata, Triconodonta and Symmetrodonta, however, these are not seen after the end of the Early Cretaceous and by the Late Cretaceous marsupials and placentals had evolved from a common eupantotherian ancestor. The Mammalia class probably saw its first eutherian in the early Cretaceous Jehol biota in China called Acristatherium yanesis and this eutherian was determined to be the most basal based on a phylogenetic analysis that used a data matrix of many other species. Metatherians probably evolved to take advantage of open arboreal niches, adaptive radiation of marsupials excluded competition with their terrestrial placental counterparts. Using this criterion, the earliest known metatherian is Sinodelphys szalayi and this makes it a contemporary to some early eutherian species that have been found in the same area. The oldest metatherian fossils are found in present-day China, from there, metatherians spread westward into modern North America, where the earliest true marsupials are found. The earliest definite marsupial fossil belongs to the species Peradectes minor, from the Paleocene of Montana, from their point of origin in Laurasia, marsupials spread to South America, which was connected to North America until around 65 mya. List of prehistoric mammals List of placental mammals List of monotremes and marsupials
26.
Xenarthra
–
The superorder Xenarthra is a group of placental mammals, extant today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced as far back as the Paleocene, xenarthrans developed and diversified extensively in South America during its long period of isolation in the early to mid Cenozoic Era. They had invaded the Antilles by the early Miocene and, starting about 9 Mya, spread to Central, nearly all of the formerly abundant megafaunal xenarthrans, such as ground sloths, glyptodonts, and pampatheres, became extinct at the end of the Pleistocene. Xenarthrans share several characteristics not present in placental mammals. The name Xenarthra, which means strange joints, was chosen because their vertebral joints have extra articulations unlike other mammals and this trait is referred to as xenarthry. Also, unlike mammals, the ischium and sacrum are fused. The males have internal testicles, which are located between the bladder and the rectum, furthermore, xenarthrans have the lowest metabolic rates among the therians. Xenarthrans were previously classified alongside the pangolins and aardvarks in the order Edentata, subsequently, Edentata was found to be a polyphyletic grouping whose New World and Old World taxa are unrelated, and it was split up to reflect their true phylogeny. Aardvarks and pangolins are now placed in orders, and the new order Xenarthra was erected to group the remaining families. The name Xenarthra means strange joints, and was chosen because their vertebral joints have extra articulations and are unlike those of any other mammals. The morphology of xenarthrans generally suggests that the anteaters and sloths are more related to each other than either is to the armadillos. Since its conception, Xenarthra has increasingly come to be considered to be of a higher rank than order, some consider it to be a cohort. Whatever the rank, Xenarthra is now considered to be divided into two orders, Cingulata, which contains the armadillos, and Pilosa, which contains the Vermilingua. Xenarthra may be most closely related to either Afrotheria, Boreoeutheria, in other words, it may be nested within Eutheria or it may be the basal extant group. A comprehensive phylogeny by Goloboff et al. includes xenarthrans as a clade of Euarchontoglires within Boreoeutheria. Below is a recent simplified phylogeny of the families based on Slater et al. The dagger symbol, †, denotes extinct groups, chen, Caoyi, Erez, Offer, Grossman, Lawrence I. Evolution of the mammalian placenta revealed by phylogenetic analysis, proceedings of the National Academy of Sciences
27.
Meridiungulata
–
Meridiungulata is an extinct clade with the rank of cohort or superorder, containing the South American ungulates Pyrotheria, Astrapotheria, Notoungulata and Litopterna. It is not known if it is a group, it was erected to distinguish the ungulates of South America from other ungulates. Relationships between the orders inside Meridiungulata remain unresolved and it could well be a wastebasket taxon and it has, however, been suggested the Meridiungulata are part of a different macro-group of placental mammals called Atlantogenata. Much of the evolution of meridiungulates occurred in isolation from other ungulates, however, the argument that meridiungulates are related to artiodactyls and perissodactyls needs support from molecular sequencing
28.
Oceanic dispersal
–
Oceanic dispersal is a type of biological dispersal that occurs when terrestrial organisms transfer from one land mass to another by way of a sea crossing. Often this occurs via large rafts of floating vegetation such as are seen floating down major rivers in the tropics and washing out to sea. Dispersal via such a raft is sometimes referred to as a rafting event, colonization of land masses by plants can also occur via long-distance oceanic dispersal of floating seeds. Both land masses, for example, appear to have received their primates by this mechanism, according to genetic evidence, the common ancestor of the lemurs of Madagascar appears to have crossed the Mozambique Channel by rafting between 50 and 60 Ma ago. Likewise, the New World monkeys are thought to have originated in Africa and rafted to South America by the Oligocene, Madagascar also appears to have received its tenrecs, nesomyid rodents and euplerid carnivorans by this route and South America its caviomorph rodents. Simian primates and hystricognath rodents are believed to have rafted from Asia to Africa about 40 Ma ago. Among reptiles, several species in the South Pacific have been hypothesized to be descended from iguanas that rafted 10,000 kilometres from Central or South America. Similarly, a number of clades of American geckos seem to have rafted over from Africa during both the Paleogene and Neogene. Skinks of the related genera Mabuya and Trachylepis also apparently both floated across the Atlantic from Africa to South America and Fernando de Noronha, respectively, skinks from the same group have also rafted from Africa to Cape Verde, Madagascar, the Seychelles, the Comoros and Socotra. Surprisingly, even burrowing amphisbaenians and blind snakes appear to have rafted from Africa to South America, an example of a bird that is thought to have reached its present location by rafting is the weak-flying South American hoatzin, whose ancestors apparently floated over from Africa. Colonization of groups of islands can occur by an iterative rafting process sometimes called island hopping, such a process appears to have played a role, for example, in the colonization of the Caribbean by mammals of South American origin. A remarkable example of iterative rafting has been proposed for spiders of the genus Amaurobioides, members of this genus inhabit coastal sites and build silken cells which they seal at high tide, however, they do not balloon. However, oceanic dispersal of species may not always take the form of rafting, in some cases. South American tortoises then went on to colonize the West Indies, the dispersal of anthracotheres from Asia to Africa about 40 Ma ago, and the much more recent dispersal of hippos from Africa to Madagascar may have occurred by floating or swimming. The first documented example of colonization of a mass by rafting occurred in the aftermath of hurricanes Luis. A raft of uprooted trees carrying fifteen or more green iguanas was observed by fishermen landing on the east side of Anguilla – an island where they had never before been recorded. The iguanas had apparently caught on the trees and rafted two hundred miles across the ocean from Guadeloupe, where they are indigenous. Examination of the patterns and ocean currents indicated that they had probably spent three weeks at sea before landfall
29.
Atlantic Ocean
–
The Atlantic Ocean is the second largest of the worlds oceans with a total area of about 106,460,000 square kilometres. It covers approximately 20 percent of the Earths surface and about 29 percent of its surface area. It separates the Old World from the New World, the Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Eurasia and Africa to the east, and the Americas to the west. The Equatorial Counter Current subdivides it into the North Atlantic Ocean, in contrast, the term Atlantic originally referred specifically to the Atlas Mountains in Morocco and the sea off the Strait of Gibraltar and the North African coast. The Greek word thalassa has been reused by scientists for the huge Panthalassa ocean that surrounded the supercontinent Pangaea hundreds of years ago. The term Aethiopian Ocean, derived from Ancient Ethiopia, was applied to the Southern Atlantic as late as the mid-19th century, many Irish or British people refer to the United States and Canada as across the pond, and vice versa. The Black Atlantic refers to the role of ocean in shaping black peoples history. Irish migration to the US is meant when the term The Green Atlantic is used, the term Red Atlantic has been used in reference to the Marxian concept of an Atlantic working class, as well as to the Atlantic experience of indigenous Americans. Correspondingly, the extent and number of oceans and seas varies, the Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea, Norwegian Sea, to the east, the boundaries of the ocean proper are Europe, the Strait of Gibraltar and Africa. In the southeast, the Atlantic merges into the Indian Ocean, the 20° East meridian, running south from Cape Agulhas to Antarctica defines its border. In the 1953 definition it extends south to Antarctica, while in later maps it is bounded at the 60° parallel by the Southern Ocean, the Atlantic has irregular coasts indented by numerous bays, gulfs, and seas. Including these marginal seas the coast line of the Atlantic measures 111,866 km compared to 135,663 km for the Pacific. Including its marginal seas, the Atlantic covers an area of 106,460,000 km2 or 23. 5% of the ocean and has a volume of 310,410,900 km3 or 23. 3%. Excluding its marginal seas, the Atlantic covers 81,760,000 km2 and has a volume of 305,811,900 km3, the North Atlantic covers 41,490,000 km2 and the South Atlantic 40,270,000 km2. The average depth is 3,646 m and the maximum depth, the bathymetry of the Atlantic is dominated by a submarine mountain range called the Mid-Atlantic Ridge. It runs from 87°N or 300 km south of the North Pole to the subantarctic Bouvet Island at 42°S, the MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR reaches above 2000 m along most of its length, the MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other
30.
Africa
–
Africa is the worlds second-largest and second-most-populous continent. At about 30.3 million km² including adjacent islands, it covers 6% of Earths total surface area and 20.4 % of its land area. With 1.2 billion people as of 2016, it accounts for about 16% of the human population. The continent includes Madagascar and various archipelagos and it contains 54 fully recognized sovereign states, nine territories and two de facto independent states with limited or no recognition. Africas population is the youngest amongst all the continents, the age in 2012 was 19.7. Algeria is Africas largest country by area, and Nigeria by population, afarensis, Homo erectus, H. habilis and H. ergaster – with the earliest Homo sapiens found in Ethiopia being dated to circa 200,000 years ago. Africa straddles the equator and encompasses numerous climate areas, it is the continent to stretch from the northern temperate to southern temperate zones. Africa hosts a diversity of ethnicities, cultures and languages. In the late 19th century European countries colonized most of Africa, Africa also varies greatly with regard to environments, economics, historical ties and government systems. However, most present states in Africa originate from a process of decolonization in the 20th century, afri was a Latin name used to refer to the inhabitants of Africa, which in its widest sense referred to all lands south of the Mediterranean. This name seems to have referred to a native Libyan tribe. The name is connected with Hebrew or Phoenician ʿafar dust. The same word may be found in the name of the Banu Ifran from Algeria and Tripolitania, under Roman rule, Carthage became the capital of the province of Africa Proconsularis, which also included the coastal part of modern Libya. The Latin suffix -ica can sometimes be used to denote a land, the later Muslim kingdom of Ifriqiya, modern-day Tunisia, also preserved a form of the name. According to the Romans, Africa lay to the west of Egypt, while Asia was used to refer to Anatolia, as Europeans came to understand the real extent of the continent, the idea of Africa expanded with their knowledge. 25,4, whose descendants, he claimed, had invaded Libya, isidore of Seville in Etymologiae XIV.5.2. Suggests Africa comes from the Latin aprica, meaning sunny, massey, in 1881, stated that Africa is derived from the Egyptian af-rui-ka, meaning to turn toward the opening of the Ka. The Ka is the double of every person and the opening of the Ka refers to a womb or birthplace
31.
Primate
–
A primate is a mammal of the order Primates. In taxonomy, primates include two distinct lineages, strepsirrhines and haplorhines, Primates arose from ancestors that lived in the trees of tropical forests, many primate characteristics represent adaptations to life in this challenging three-dimensional environment. Most primate species remain at least partly arboreal, with the exception of humans, who inhabit every continent except for Antarctica, most primates live in tropical or subtropical regions of the Americas, Africa and Asia. Based on fossil evidence, the earliest known true primates, represented by the genus Teilhardina, an early close primate relative known from abundant remains is the Late Paleocene Plesiadapis, c. Molecular clock studies suggest that the branch may be even older. The order Primates was traditionally divided into two groupings, prosimians and anthropoids. Prosimians have characteristics more like those of the earliest primates, and include the lemurs of Madagascar, lorisoids, simians include monkeys, apes and hominins. Simians are divided into two groups, catarrhine monkeys and apes of Africa and Southeast Asia and platyrrhine or New World monkeys of South, catarrhines consist of Old World monkeys, gibbons and great apes, New World monkeys include the capuchin, howler and squirrel monkeys. Humans are the only extant catarrhines to have spread successfully outside of Africa, South Asia, New primate species are still being discovered. More than 25 species were described in the decade of the 2000s. Considered generalist mammals, primates exhibit a range of characteristics. Some primates are primarily terrestrial rather than arboreal, but all species possess adaptations for climbing trees, locomotion techniques used include leaping from tree to tree, walking on two or four limbs, knuckle-walking, and swinging between branches of trees. Primates are characterized by large brains relative to other mammals, as well as a reliance on stereoscopic vision at the expense of smell. These features are developed in monkeys and apes and noticeably less so in lorises. Three-color vision has developed in some primates, most also have opposable thumbs and some have prehensile tails. Many species are dimorphic, differences include body mass, canine tooth size. Primates have slower rates of development than other similarly sized mammals and reach maturity later, depending on the species, adults may live in solitude, in mated pairs, or in groups of up to hundreds of members. The relationships among the different groups of primates were not clearly understood until relatively recently, for example, ape has been used either as an alternative for monkey or for any tailless, relatively human-like primate
32.
Great American Interchange
–
The migration peaked dramatically around three million years ago during the Piacenzian age. It resulted in the joining of the Neotropic and Nearctic ecozones definitively to form the Americas, the interchange is visible from observation of both biostratigraphy and nature. Its most dramatic effect is on the zoogeography of mammals but it gave an opportunity for reptiles, amphibians, arthropods, weak-flying or flightless birds. The occurrence of the interchange was first discussed in 1876 by the father of biogeography, Wallace had spent 1848–1852 exploring and collecting specimens in the Amazon basin. Others who made significant contributions to understanding the event in the century that followed include Florentino Ameghino, W. D. Matthew, scott, Bryan Patterson, George Gaylord Simpson and S. David Webb. Analogous interchanges occurred earlier in the Cenozoic, when the formerly isolated land masses of India and Africa made contact with Eurasia c.50 and 30 Ma ago, respectively. Its endemic mammals initially consisted primarily of metatherians, xenarthrans, and a group of native ungulates, notoungulates, litopterns, astrapotheres. Marsupials appear to have traveled via Gondwanan land connections from South America through Antarctica to Australia in the late Cretaceous or early Tertiary, a 61-Ma-old platypus-like monotreme fossil from Patagonia may represent an Australian immigrant. Paleognath birds may have migrated by this route around the same time, other taxa that may have dispersed by the same route are parrots, chelid turtles and meiolaniid turtles. Marsupials present in South America included didelphimorphs and several small groups, larger predatory relatives of these also existed, like the borhyaenids. Metatherians were the only South American mammals to specialize as carnivores, sparassodonts shared the ecological niches for large predators with fearsome flightless terror birds, whose closest extant relatives are the seriemas. Terrestrial ziphodont sebecid crocodilians were also present at least through the middle Miocene, some of South Americas aquatic crocodilians, such as Gryposuchus, Mourasuchus and Purussaurus, reached monstrous sizes, with lengths up to 12 m. They shared their habitat with one of the largest turtles of all time, xenarthrans are a curious group of mammals that developed morphological adaptations for specialized diets very early in their history. The notoungulates and litopterns had many forms, like Macrauchenia. Both groups started evolving in the Lower Paleocene, possibly from condylarth stock, diversified, dwindled before the great interchange, the pyrotheres and astrapotheres were also strange but were less diverse and disappeared earlier, well before the interchange. The North American fauna was a typical boreoeutherian one, the invasions of South America started about 40 Ma ago, when caviomorph rodents arrived in South America. Their subsequent vigorous diversification displaced some of South Americas small marsupials and gave rise to – among others – capybaras, chinchillas, viscachas and this invasion most likely came from Africa. The crossing from West Africa to the northeast corner of Brazil was much shorter then, due to continental drift, crossings of the ocean were accomplished when at least one fertilised female accidentally floated over on driftwood or mangrove rafts
33.
Cladistics
–
Therefore, members of a group are assumed to share a common history and are considered to be closely related. The techniques and nomenclature of cladistics have been applied to other disciplines, Cladistics in the original sense refers to a particular set of methods used in phylogenetic analysis, although it is now sometimes used to refer to the whole field. What is now called the cladistic method appeared as early as 1901 with a work by Peter Chalmers Mitchell for birds and subsequently by Robert John Tillyard in 1921, Hennig referred to his own approach as phylogenetic systematics. Phenetics was championed at this time by the numerical taxonomists Peter Sneath and Robert Sokal, originally conceived, if only in essence, by Willi Hennig in a book published in 1950, cladistics did not flourish until its translation into English in 1966. Today, cladistics is the most popular method for constructing phylogenies from morphological, unlike phenetics, cladistics is specifically aimed at reconstructing evolutionary histories. The way for computational phylogenetics was paved by phenetics, a set of commonly used from the 1950s to 1980s. Phenetics did not try to reconstruct phylogenetic trees, rather, it tried to build dendrograms from similarity data, the cladistic method interprets each character state transformation implied by the distribution of shared character states among taxa as a potential piece of evidence for grouping. The outcome of an analysis is a cladogram – a tree-shaped diagram that is interpreted to represent the best hypothesis of phylogenetic relationships. Cladists contend that these models are unjustified, every cladogram is based on a particular dataset analyzed with a particular method. Different datasets and different methods, not to mention violations of the mentioned assumptions, only scientific investigation can show which is more likely to be correct. Since the cladograms provide competing accounts of events, at most one of them is correct. Within the primates, all anthropoids are hypothesized to have had a common ancestor all of whose descendants were anthropoids, the prosimians, on the other hand, form a paraphyletic taxon. When two or more taxa that are not nested within each other share a plesiomorphy, it is a symplesiomorphy, symplesiomorphies do not mean that the taxa that exhibit that character state are necessarily closely related. For example, Reptilia is traditionally characterized by being cold-blooded, whereas birds are warm-blooded, an apomorphy or derived state is an innovation. It can thus be used to diagnose a clade – or even to help define a clade name in phylogenetic nomenclature, features that are derived in individual taxa are called autapomorphies. Autapomorphies express nothing about relationships among groups, clades are identified by synapomorphies, for example, the possession of digits that are homologous with those of Homo sapiens is a synapomorphy within the vertebrates. The tetrapods can be singled out as consisting of the first vertebrate with such digits homologous to those of Homo sapiens together with all descendants of this vertebrate and it is therefore inferred to have evolved by convergence or reversal. Both mammals and birds are able to maintain a constant body temperature
34.
Extinction
–
In biology and ecology, extinction is the end of an organism or of a group of organisms, normally a species. The moment of extinction is considered to be the death of the last individual of the species, although the capacity to breed. Because a species range may be very large, determining this moment is difficult. This difficulty leads to such as Lazarus taxa, where a species presumed extinct abruptly reappears after a period of apparent absence. More than 99 percent of all species, amounting to five billion species. Estimates on the number of Earths current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described, the relationship between animals and their ecological niches has been firmly established. Mass extinctions are relatively rare events, however, isolated extinctions are quite common, only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions. Most species that become extinct are never scientifically documented, some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100. A dagger symbol next to a name is often used to indicate its extinction. A species is extinct when the last existing member dies, Extinction therefore becomes a certainty when there are no surviving individuals that can reproduce and create a new generation. Pinpointing the extinction of a species requires a definition of that species. If it is to be declared extinct, the species in question must be distinguishable from any ancestor or daughter species. Extinction of a plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould. In ecology, extinction is often used informally to refer to local extinction, in which a species ceases to exist in the area of study. This phenomenon is known as extirpation. Local extinctions may be followed by a replacement of the species taken from other locations, species which are not extinct are termed extant. Those that are extant but threatened by extinction are referred to as threatened or endangered species, currently an important aspect of extinction is human attempts to preserve critically endangered species
35.
Diatomyidae
–
The hystricomorphous sciurognathous rodent family Diatomyidae, found in Asia, is represented by a single known living species, Laonastes aenigmamus. Prior to the discovery of Laonastes, the family Diatomyidae was known only from fossils, the family has a nearly continuous fossil range from Early Oligocene fossils of Fallomus from the Lower Chitarwata Formation in Balochistan, Pakistan, to Middle/Late Miocene fossils of Diatomys. Jenkins et al. reported the discovery of a unique new species of rodent, Laonastes aenigmamus, for which they created a new family. They suggested it was a rodent, but basal to all other hystricognaths. Dawson, et al, re-evaluated the phylogenetic position of Laonastes based on morphology and they determined Laonastes is actually sciurognathous and belongs to the Diatomyidae. They also described the Diatomyidae as a Lazarus taxon due to the 11-million-year gap between the most recent diatomyid in the record and the existence of Laonastes today. The only other comparable length of time for a mammal Lazarus taxon is the monito del monte, mary Dawson described Laonastes as the coelacanth of rodents. The Diatomyidae are similar to both the Ctenodactylidae and the Anomaluromorpha in being simultaneously hystricomorphous and sciurognathous, the masseteric fossa in diatomyids is enlarged and extends to below the first cheek tooth. The enamel on incisors is multiserial, the single premolar on both the upper and lower tooth rows is enlarged. Most diatomyids have cheek teeth with four roots except for the first, in Laonastes, the lower molars have four roots, but upper cheek teeth have three roots including a U-shaped anterior root that may be derived from the merging of two roots. Living diatomyids are only represented by the Laotian rock rat from the Khammouan region of Laos, fossil diatomyids have been recovered in Pakistan, India, Thailand, China, Japan, and Saudi Arabia. The uniqueness of the Laotian rock rat was clear upon its initial discovery, the results of the phylogenetic analyses were somewhat inconclusive and contradictory. Both morphological and molecular studies suggested Laonastes is a member of the rodent suborder Hystricognathi, the morphological analysis suggested it is the most basal hystricognath. Fossil taxa were not included in the morphological analysis, analysis of mtDNA 12S rRNA and cytochrome b sequence, however, suggested Laonastes might be related to living African hystricognaths such as the dassie rat and the naked mole rat. Another type of analysis on the cytochrome b sequence data produced the result as morphology. Neither analysis, however, showed entirely robust statistical support for the position of Laonastes within the hystricognaths, altogether, Dawson et al. also refuted the notion that Laonastes is a hystricognath and instead argued that the mandible is sciurognathous. They evaluated Laonastes in comparison to several fossil rodents and determined it is related to the diatomyids. Their results suggested the Diatomyidae are a group to the Ctenodactylidae
36.
Laotian rock rat
–
The Laotian rock rat or kha-nyou, sometimes called the rat-squirrel, is a rodent species of the Khammouan region of Laos. The species was first described in a 2005 article by Paulina Jenkins and coauthors and it is in the monotypic genus Laonastes. In 2006, the classification of the Laotian rock rat was disputed by Mary Dawson, Dawson and her colleagues suggested instead it belongs to the ancient fossil family Diatomyidae, that was thought to have been extinct for 11 million years, since the late Miocene. It would thereby represent a Lazarus taxon, the animals resemble large, dark rats with hairy, thick tails like those of a squirrel. Their skulls are distinctive and have features that separate them from all other living mammals. Upon their initial discovery, Jenkins and coauthors considered the Laotian rock rat to represent a new family. The discovery of a new species of an extant mammal genus happens periodically, the discovery of a completely new family is, by comparison, much more unusual. The most recent incident before the discovery of the family Laonastidae by Western science was the discovery of the bat in 1974. The only other examples from the 20th century are species that are considered distinct families by a few authorities. These discoveries are, the Chinese river dolphin in 1918, the Zagros mouse-like hamster in 1905, representatives from all the remaining rodent families with living representatives were discovered before 1900. Jenkins et al. did not compare the specimens to known rodent fossils, after such a comparison, Dawson et al. were of the opinion that the Laotian rock rat belongs to a previously described family which had only been known from fossils, the Diatomyidae. The Diatomyidae are known from a series of fossils from the early Oligocene until the Miocene, the discovery of the Laotian rock rat means an 11 million-year gap exists in the fossil record where no diatomyids have been found. Dawson et al. described the Diatomyidae as a Lazarus taxon due to this gap, Mary Dawson described Laonastes as the coelacanth of rodents. The analysis of mtDNA 12S rRNA and cytochrome b sequence by Jenkins et al. allied Laonastes with African hystricognath rodents, namely the blesmols, support for such a placement was fair, but the exact position could not be resolved. Their molecular data place Laonastes robustly as a clade of Ctenodactylidae. The earlier molecular study was in due to long branch attraction. The genus name for this animal, Laonastes, means inhabitant of stone and this is in reference to its presence around limestone rocks and also to the country where it was recently discovered. The specific epithet aenigmamus means enigma mouse referring to its position among the rodents
37.
Hystricidae
–
The Old World porcupines, or Hystricidae, are large terrestrial rodents, distinguished by the spiny covering from which they take their name. They range over the south of Europe and the Levant, most of Africa, India, although both the Old World and New World porcupine families belong to the Hystricognathi branch of the vast order Rodentia, they are quite different and are not closely related. The habits of most species are strictly terrestrial, the various species are typically herbivorous, eating fruit, roots, and bulbs. Some species also gnaw on dry bones, perhaps as a source of calcium, like other rodents, they have powerful gnawing incisors, and no canine teeth. Their dental formula is 1.0.1.31.0.1.3 One or two young are born after a period between 90 and 112 days, depending on the species. Females typically give birth once a year, in a grass-lined underground chamber within a burrow system. The young are more or less fully developed, and the spines. Although they begin to take solid food within two weeks, they are not fully weaned until 13 to 19 weeks after birth. The young remain with the colony until they reach maturity at around two years of age, and share the burrow system with their parents and siblings from other litters. Males, in particular, help defend the colony from intruders, the crested porcupine, a typical representative of the Old World porcupines, occurs throughout the south of Europe and North and West Africa. It is replaced in South Africa by the Cape porcupine, H. africaeaustralis, the latter also lives throughout the Middle East. Besides these large-crested species, several smaller species without crests occur in northeast India, the genus Atherurus includes the brush-tailed porcupines which are much smaller animals, with long tails tipped with bundles of flattened spines. One species is found in the Malay region and one in Central, the latter species, the African brush-tailed porcupine, is often hunted for its meat. Trichys, the last genus, contains one species, the porcupine of Borneo. This species is very similar to Atherurus, but differs from the members of that genus in many cranial characteristics. Fossil species are known from Africa and Eurasia, with one of the oldest being Sivacanthion from the Miocene of present-day Pakistan. However, it was not a direct ancestor of modern porcupines. and Bell. Classification of Mammals Above the Species Level, columbia University Press, New York,631 pp. ISBN 0-231-11013-8
38.
Phiomorpha
–
The rodent parvorder or infraorder Phiomorpha comprises several living and extinct families found wholly or largely in Africa. Along with the Anomaluromorpha and perhaps the †Zegdoumyidae, they represent one of the few early colonizations of Africa by rodents, during the Oligocene, Africa was not connected to any of the other continents. The predominant theory suggests that rodents first evolved in Laurasia, the southern continents were much more isolated leading to the unique faunas of Australia, South America, and to a lesser degree Africa. Although the hystricognath rodents may have evolved from an early entodacryan ancestor in Asia, the Phiomorpha represents the clade that evolved as a result. Although once diverse, this infraorder is now restricted to the two species of rats, the dassie rat, and the blesmols. The makeup of this infraorder is controversial, at its core lie the extant families Thryonomyidae, Petromuridae, and Bathyergidae and their extinct relatives. The Old World porcupines are sometimes included in the Phiomorpha, molecular results suggest that the Diatomyidae is a part of the Phiomorpha, but this is in contrast to morphological results which place the animal at a basal position to all hystricognaths. From the Old World to the New World, A molecular chronicle of the phylogeny, marivaux, L. M. Vianey-Liaud, and J. -J. High-level phylogeny of early Tertiary rodents, dental evidence, zoological Journal of the Linnean Society,142, 105-134. McKenna, Malcolm C. and Bell, Susan K.1997, classification of Mammals Above the Species Level. Columbia University Press, New York,631 pp. ISBN 0-231-11013-8 Caviomorpha Hystricomorpha Hystricognathi Laotian Rock Rat
39.
Dassie rat
–
The dassie rat is an African rodent found among rocky outcroppings. It is the only living member of its genus, Petromus, the name dassie means hyrax in Afrikaans, and the two animals are found in similar habitats. Petromus means rock mouse and dassie rats are one of many rodents sometimes called rock rats, the family and genus names are sometimes misspelled as Petromyidae and Petromys. Dassie rats are squirrel-like in appearance and their tails are hairy, but not bushy whereas the soles of their feet are distinctly bare and have pads. The overall coloration can be a range of browns, greys, the nose is yellowish and tends to stand out. The teats are located on the sides of the torso, which allows the young to feed from the side when crammed in a rock crevice. Dassie rats are restricted to rocky outcrops in Namibia, parts of Angola and they are famous for being able to squeeze into extremely narrow crevices. This is accomplished due to their skulls and flexible ribs. Dassie rats feed primarily on grasses, but will eat fruits, seeds. They have high crowned and rooted cheek teeth, females give birth to a pair of offspring just once a year, an unusually slow reproductive rate among rodents. Dassie rats are the remaining members of a once-diverse family that first appeared in the Oligocene of Africa. Both morphological and molecular studies suggest the closest living relatives to the rats are the African cane rats in the family Thryonomyidae. These two families, along with related fossil families such as †Phiomyidae, represented an important early radiation of rodents in Africa, the Kingdon Field Guide to African Mammals. McKenna, Malcolm C. and Bell, Susan K.1997, classification of Mammals Above the Species Level. Columbia University Press, New York,631 pp. ISBN 0-231-11013-8 Nowak, walkers Mammals of the World, Vol.2. Animal Diversity Web site about dassie rats The Dassie Rat, Focusing On Wildlife
40.
Cane rat
–
The genus Thryonomys, also known as the cane rats, is a genus of rodent found throughout Africa south of the Sahara, the only members of the family Thryonomyidae. They are eaten in some African countries and are a pest species on many crops, the family name comes from the Greek word thryon, meaning a rush or reed. Cane rats range in length from 35 to 60 centimetres. They commonly weigh 6-7 kilograms in captivity, and can attain weights up to 10 kilograms in the wild and they are heavily built rodents, with bristly brown fur speckled with yellow or grey. They live in areas and along river and lake banks. In agricultural areas they also, as the name suggests, feed on the crops in cane plantations. Females give birth to litters of two to four young at least once a year, and more frequently in some areas, cane rats are sexually mature and able to reproduce at 6 months of age. Cane rats are widely distributed and farmers expend substantial energy fencing the rodents out of their fields, like the guinea pig, the meat is of a higher protein but lower fat content than domesticated farm meat and it is also appreciated for its tenderness and taste. In the savanna area of West Africa, people have traditionally captured wild cane rats, practical information is now more readily available for farmers interested in cane rat breeding, but training is still advised. There are areas where they have been over-hunted, and savanna habitat is often at risk during the dry season from bushfires, the Value of Grasscutters, World Ark, pp. 23–24. BBC article on grasscutter rearing in Ghana
41.
Blesmol
–
The blesmols, also known as mole-rats, or African mole-rats, are burrowing rodents of the family Bathyergidae. They represent an evolution of a subterranean life among rodents much like the pocket gophers of North America. Modern blesmols are found strictly in sub-Saharan Africa, fossil forms are also restricted almost exclusively to Africa, although a few specimens of the Pleistocene species Cryptomys asiaticus have been found in Israel. Nowak also reports that †Gypsorhynchus has been found in deposits of Mongolia. Blesmols are somewhat mole-like animals with bodies and short limbs. They range from 9 to 30 cm in length, and from 30 to 1,800 g in weight, blesmols, like many other fossorial mammals, have greatly reduced eyes and ear pinnae, a relatively short tail, loose skin, and velvety fur. Blesmols have very poor vision, although they may use the surfaces of their eyes for sensing air currents, despite their small or absent pinnae, they have a good sense of hearing, although their most important sense appears to be that of touch. Like other rodents, they have an excellent sense of smell, the eyes of blesmols are structurally normal, despite their relatively small size, and include normal light-sensitive cells. However, the centres of their brains are reduced in certain respects. Research has shown that at least two species of blesmol are not blind, as believed, and will actively avoid blue or green-yellow light. They do not appear able to detect the presence of red light, the ability to sense the presence of light is probably useful in allowing them to detect breaches in their tunnel systems and repair them promptly. Most blesmol species dig using their incisors and, to a lesser extent. Dune blesmols aside, some species have been reported to be able to extend their burrows by an inch into the walls of concrete enclosures. Their unique skull shape is associated with delivering sheer power to the masseter muscle which is responsible for the powerful bite of the anterior portion of the mouth. The incisors of blesmols are projected forward and protrude from the mouth even when the mouth is closed and this condition allows the animals to burrow with their teeth without getting dirt in their mouths. As with all members of their suborder, their jaws are hystricognathous, the medial masseter muscle shows only minimal passage through the infraorbital foramen leading most authorities to consider them protrogomorphous. They are therefore the only protrogomorphous hystricognaths, blesmols live in elaborate burrow systems and different species exhibit varying degrees of sociality. Most species are solitary, but two species, the damaraland blesmol and the naked mole-rat are considered to be the only two eusocial mammals and these species are characterized by having a single reproductively active male and female in a colony where the remaining animals are sterile
42.
New World porcupine
–
The New World porcupines, family Erethizontidae, are large arboreal rodents, distinguished by their spiny coverings from which they take their name. They inhabit forests and wooded regions across North America, and into northern South America, although both the New World and Old World porcupine families belong to the Hystricognathi branch of the vast order Rodentia, they are quite different and are not closely related. New World porcupines are stout animals, with blunt, rounded heads, fleshy, mobile snouts, the spines are mixed with long, soft hairs. They are distinguished from the Old World porcupines in that they have rooted molars, complete collar bones, entire upper lips, tuberculated soles, no trace of first front toes, and four teats. They are less strictly nocturnal than Old World species in their habits and their long and powerful prehensile tails help them balance when they are in the tree tops. Their diets consist mainly of bark, leaves, and conifer needles, but can also include roots, stems, berries, fruits, seeds, nuts, grasses, some species also eat insects and small reptiles. Their teeth are similar to those of Old World porcupines, with the dental formula 1.0.1.31.0.1.3 Solitary offspring are born after a period of up to 210 days. The young are fully developed, with open eyes, and are able to climb trees within a few days of birth. It is a native of the part of Canada and the United States. The tree porcupines contain 16 species and they are found throughout tropical South America, with two extending into Mexico. They are of a lighter build than the ground porcupines, with short, close, many-coloured spines, often mixed with hairs and these three genera are often united into a single genus Coendou. Genus Chaetomys, distinguished by the shape of its skull and the complexity of its teeth, contains C. subspinosus. This animal is considered a member of Echimyidae on the basis of its premolars
. PMID 21993503.
