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Oryzomys Palustris Mandible Caps
''Oryzomys'' is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (''O. palustris'') of the United States and '' O. couesi'' of Mexico and Central America—are widespread; the six others have more restricted distributions. The species have had eventful taxonomic histories, and most species were at one time included in the marsh rice rat; additional species may be recognized in the future. The name ''Oryzomys'' was established in 1857 by Spencer Fullerton Baird for the marsh rice rat and was soon applied to over a hundred species of American rodents. Subsequently, the genus gradually became more narrowly defined until its current contents were established in 2006, when ten new genera were established for species previously placed in ''Oryzomys''. Species of ''Oryzomys'' are medium-sized rats with long, coarse fur. The upperparts are gray to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rancholabrean
The Rancholabrean North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from less than 240,000 years to 11,000 years BP, a period of .Sanders, A.E., R.E. Weems, and L.B. Albright III (2009) Formalization of the mid-Pleistocene "Ten Mile Hill beds" in South Carolina with evidence for placement of the Irvingtonian–Rancholabrean boundary, ''Museum of Northern Arizona Bulletin'' 64:369-375 Named after the famed Rancho La Brea fossil site (more commonly known as the La Brea tar pits) in Los Angeles, California,Savage, D.E. (1951) Late Cenozoic vertebrates of the San Francisco Bay region, ''University of California Publications, Bulletin of the Department of Geological Sciences'' 28:215-314 the Rancholabrean is characterized by the presence of the genus '' Bison'' in a Pleistocene context, often in association with other extinct Pleistocene forms such as ''Mammuth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as Armillaria mellea, honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the Orobanchaceae, broomrapes. There are six major parasitic Behavioral ecology#Evolutionarily stable strategy, strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), wikt:trophic, trophicallytransmitted parasitism (by being eaten), Disease vector, vector-transmitted parasitism, parasitoidism, and micropreda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestation Period
In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus. Fertilization and implantation During copulation, the male inseminates the female. The spermatozoon fertilizes an ovum or various ova in the uterus or fallopian tubes, and this results in one or multiple zygotes. Sometimes, a zygote can be created by humans outside of the animal's body in the artificial process of in-vitro fertilization. After fertilization, the newly formed zygote then begins to divide through mitosis, forming an embryo, which implants in the female's endometrium. At this time, the embryo usually consists of 50 cells. Development After implantation A blastocele is a small cavity on the center of the embryo, and the developing embryonary cells will grow around it. Then, a flat layer cell forms on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical manifestation of its ecological niche. Thus "habitat" is a species-specific term, fundamentally different from concepts such as environment or vegetation assemblages, for which the term "habitat-type" is more appropriate. The physical factors may include (for example): soil, moisture, range of temperature, and light intensity. Biotic factors will include the availability of food and the presence or absence of predators. Every species has particular habitat requirements, with habitat generalist species able to thrive in a wide array of environmental conditions while habitat specialist species requiring a very limited set of factors to survive. The habitat of a species is not necessarily found in a geographical area, it can be the interior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gall Bladder
In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although the structure and position of the gallbladder can vary significantly among animal species. It receives and stores bile, produced by the liver, via the common hepatic duct, and releases it via the common bile duct into the duodenum, where the bile helps in the digestion of fats. The gallbladder can be affected by gallstones, formed by material that cannot be dissolved – usually cholesterol or bilirubin, a product of haemoglobin breakdown. These may cause significant pain, particularly in the upper-right corner of the abdomen, and are often treated with removal of the gallbladder (called a cholecystectomy). Cholecystitis, inflammation of the gallbladder, has a wide range of causes, including result from the impaction of gallstones, infec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braincase
In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skullcap. The remainder of the skull is the facial skeleton. In comparative anatomy, neurocranium is sometimes used synonymously with endocranium or chondrocranium. Structure The neurocranium is divided into two portions: * the membranous part, consisting of flat bones, which surround the brain; and * the cartilaginous part, or chondrocranium, which forms bones of the base of the skull. In humans, the neurocranium is usually considered to include the following eight bones: * 1 ethmoid bone * 1 frontal bone * 1 occipital bone * 2 parietal bones * 1 sphenoid bone * 2 temporal bones The ossicles (three on each side) are usually not included as bones of the neurocranium. There may variably also be extra sutural bones present. Below the ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interdigital Webbing
Interdigital webbing is the presence of membranes of skin between the digits. Normally in mammals, webbing is present in the embryo but resorbed later in development, but in various mammal species it occasionally persists in adulthood. In humans, it can be found in those suffering from LEOPARD syndrome and from Aarskog–Scott syndrome. Webbing between the digits of the hindfoot is also present in several mammals that spend part of their time in the water.Voss, 1988, p. 455 Webbing accommodates movement in the water.Voss, 1988, p. 458 Interdigital webbing is not to be confused with syndactyly, which is a fusing of digits and occurs rarely in humans. Syndactyly specifically affecting feet occurs in birds (such as ducks), amphibians (such as frogs), and mammals (such as the kangaroo). Mammals with interdigital webbing Rodents In oryzomyines, a mainly South American rodent group, the marsh rice rat, '' Pseudoryzomys simplex'', and ''Sigmodontomys alfari'' all have small webs, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ungual Tufts
In mammals, ungual tufts are tufts of hairs at the base of claws of the forefeet and hindfeet. Their presence has been used as a character in cladistic studies of the Cricetidae, a large family of rodents.Weksler, 2006, p. 19 Rice rats Members of the tribe Oryzomyini ("rice rats"), in the Cricetidae subfamily Sigmodontinae, normally have ungual tufts, but they may be reduced or absent in semiaquatic species (i.e. those adapted to life in the water).Weksler, 2006, p. 81 ''Lundomys molitor'', '' Nectomys apicalis'', the marsh rice rat (''Oryzomys palustris''), and species of ''Holochilus'' lack ungual tufts on their forefeet.Weksler, 2006, p. 23 On the hindfeet, most species have well-developed ungual tufts only on the second to fifth toes, but '' Sooretamys angouya'' and '' Eremoryzomys polius'' also have thick tufts on the first toe. '' Pseudoryzomys simplex'', '' Mindomys hammondi'', '' Nectomys squamipes'', ''Sigmodontomys alfari'', '' Oryzomys couesi'', the marsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buff (colour)
Buff (latin ''bubalinus'') is a light brownish yellow, ochreous colour, typical of buff leather. Buff is a mixture of yellow ochre and white: two parts of white lead and one part of yellow ochre produces a good buff, or white lead may be tinted with French ochre alone. As an RYB quaternary colour, it is the colour produced by an equal mix of the tertiary colours citron and russet. Etymology The first recorded use of the word ''buff'' to describe a colour was in ''The London Gazette'' of 1686, describing a uniform to be "...a Red Coat with a Buff-colour'd lining". It referred to the colour of undyed buffalo leather, such as soldiers wore as some protection: an eyewitness to the death in the Battle of Edgehill (1642) of Sir Edmund Verney noted "he would neither put on arms rmouror buff coat the day of the battle". Such buff leather was suitable for ''buffing'' or serving as a ''buffer'' between polished objects. It is not clear which bovine "''buffalo''" referred to, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxonomy (biology)
In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a more inclusive group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum (''division'' is sometimes used in botany in place of ''phylum''), class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, as he developed a ranked system known as Linnaean taxonomy for categorizing organisms and binomial nomenclature for naming organisms. With advances in the theory, data and analytical technology of biological systematics, the Linnaean system has transformed into a system of modern biological classification intended to reflect the evolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.JPG "Click for more on -> Habitat")
