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Flat-tail Horned Lizard
The flat-tail horned lizard (''Phrynosoma mcallii'') is a species of lizard in the family Phrynosomatidae. A species of reptile, it is endemic to the Sonoran Desert of the southwestern United States and northwestern Mexico. Its multiple adaptations for camouflage help to minimize its shadow. The species is threatened, with a restricted range under pressure from human activities such as agriculture and development, and is specially protected in the United States. Description and geographic range The flat-tail horned lizard is named for United States Army Colonel George A. M'Call,Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (''Phrynosoma mcallii'', p. 172). who collected the first specimen in California in the 19th century. The species occupies a small range in the Sonoran Desert of southeastern California, southwestern Arizona, and extreme northern Mexico in the Baja Calif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darrel R
Darrel is a given name. Notable people with the name include: * Darrel Akerfelds (1962–2012), American baseball pitcher and bullpen coach * Darrel Anholt (born 1962), Canadian ice hockey defenceman * Darrel Aschbacher (born 1935), American football player * Darrel Aubertine (born 1953), American politician in the New York State Senate * Darrel Baldock (1938–2011), Australian rules football player and coach * Darrel Brown (born 1984), sprinter from Trinidad and Tobago * Darrel Brown (basketball) (1923–1990), American basketball player * Darrel Castillo (born 1992) Guatemalan judoka * Darrel Chaney (born 1948), American baseball player and announcer * Darrel Chapman (1937–1992), Australian rugby league player * Darrel Cunningham (born 1948), Canadian politician * Darrel R. Falk (born 1946), American biologist * Darrel Frost (born 1951), American herpetologist and systematist * Darrel Guilbeau (born 1962), American actor * Darrel Verner Heald (1919–2010), Canadi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundary, maritime boundaries with the Pacific Ocean to the west, the Caribbean Sea to the southeast, and the Gulf of Mexico to the east. Mexico covers 1,972,550 km2 (761,610 sq mi), and is the List of countries by area, thirteenth-largest country in the world by land area. With a population exceeding 130 million, Mexico is the List of countries by population, tenth-most populous country in the world and is home to the Hispanophone#Countries, largest number of native Spanish speakers. Mexico City is the capital and List of cities in Mexico, largest city, which ranks among the List of cities by population, most populous metropolitan areas in the world. Human presence in Mexico dates back to at least 8,000 BC. Mesoamerica, considered a cradle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reptiles Of The United States
Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and amniotic development. Living traditional reptiles comprise four orders: Testudines, Crocodilia, Squamata, and Rhynchocephalia. About 12,000 living species of reptiles are listed in the Reptile Database. The study of the traditional reptile orders, customarily in combination with the study of modern amphibians, is called herpetology. Reptiles have been subject to several conflicting taxonomic definitions. In Linnaean taxonomy, reptiles are gathered together under the class Reptilia ( ), which corresponds to common usage. Modern cladistic taxonomy regards that group as paraphyletic, since genetic and paleontological evidence has determined that birds (class Aves), as members of Dinosauria, are more closely related to living crocodilians than to other reptiles, and are thus nested among reptiles from an evolutionary perspective. Many cladistic systems therefore redefine Reptilia as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reptiles Described In 1852
Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocephalia. About 12,000 living species of reptiles are listed in the Reptile Database. The study of the traditional reptile orders, customarily in combination with the study of modern amphibians, is called herpetology. Reptiles have been subject to several conflicting Taxonomy, taxonomic definitions. In Linnaean taxonomy, reptiles are gathered together under the Class (biology), class Reptilia ( ), which corresponds to common usage. Modern Cladistics, cladistic taxonomy regards that group as Paraphyly, paraphyletic, since Genetics, genetic and Paleontology, paleontological evidence has determined that birds (class Aves), as members of Dinosauria, are more closely related to living crocodilians than to other reptiles, and are thus nested among re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phrynosoma
''Phrynosoma'', whose members are known as the horned lizards, horny toads, or horntoads, is a genus of North American lizards and the type genus of the family Phrynosomatidae. Their common names refer directly to their horns or to their flattened, rounded bodies (squat bodied), and blunt snouts. The generic name ''Phrynosoma'' means "toad-bodied". In common with true toads (amphibians of the family Bufonidae), horned lizards tend to move sluggishly, often remain motionless, and rely on their remarkable camouflage to avoid detection by predators. They are adapted to arid or semiarid areas. The spines on the lizard's back and sides are modified reptile scales, which prevent water loss through the skin, whereas the horns on the head are true horns (i.e., they have a bony core). A urinary bladder is absent. Of the 21 species of horned lizards, 15 are native to the USA. The largest-bodied and most widely distributed of the American species is the Texas horned lizard. Defenses Hor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messor Pergandei
''Veromessor pergandei'' is a species of harvester ant native to the Southwestern United States, especially the deserts of southeastern California. It has also been identified in the Baja California peninsula of Mexico. It was first described by Gustav Mayr, who named it ''Aphaenogaster pergandei''. It can also be referred to as a black harvester ant or desert harvester ant, although these common names have also been applied to other species. Description ''V. pergandei'' has a head of equal length and width, with very large mandibles. It has short white or yellow hair and a large thorax. Males typically measure about and females about . However, individual size can vary based on factors such as availability of food and interspecific competition. The species is named after American myrmecologist Theodore Pergande. The genus was for some time synonymized under ''Messor'' but has been split out based on a 2015 study. Veromessor_pergandei-mound.jpg, nest mound Veromessor_pergandei- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Whiptail
The western whiptail (''Aspidoscelis tigris'') is a species of lizard in the Family (biology), family Teiidae. The species is found throughout most of the southwestern United States and northern Mexico. Most of its populations appear stable, and it is not listed as endangered in any of the states comprising its range. It lives in a wide variety of habitats, including deserts and semiarid shrubland, usually in areas with sparse vegetation; it also may be found in woodland, open dry forest, and riparian growth. It lives in burrows. Major differences between this species and the checkered whiptail (''Aspidoscelis tesselatus'') include the lack of enlarged scales anterior to the gular fold and the presence of enlarged postantebrachial scales. It was previously known as ''Cnemidophorus tigris'', until phylogenetics, phylogenetic analyses concluded that the genus ''Cnemidophorus'' was polyphyletic. Since it does not migrate, a number of forms have developed in different regions, severa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disruptive Pattern
Disruptive coloration (also known as disruptive camouflage or disruptive patterning) is a form of camouflage that works by breaking up the outlines of an animal, soldier or military hardware with a strongly contrasting pattern. It is often combined with other methods of crypsis including background colour matching and countershading; special cases are coincident disruptive coloration and the disruptive eye mask seen in some fishes, amphibians, and reptiles. It appears paradoxical as a way of not being seen, since disruption of outlines depends on high contrast, so the patches of colour are themselves conspicuous. The importance of high-contrast patterns for successful disruption was predicted in general terms by the artist Abbott Thayer in 1909 and explicitly by the zoologist Hugh Cott in 1940. Later experimental research has started to confirm these predictions. Disruptive patterns work best when all their components match the background. While background matching works b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridophores
Chromatophores are cells that produce color, of which many types are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contrast, have a class of cells called melanocytes for coloration. Chromatophores are largely responsible for generating skin and eye colour in ectothermic animals and are generated in the neural crest during embryonic development. Mature chromatophores are grouped into subclasses based on their colour under white light: xanthophores (yellow), erythrophores (red), iridophores (reflective / iridescent), leucophores (white), melanophores (black/brown), and cyanophores (blue). While most chromatophores contain pigments that absorb specific wavelengths of light, the color of leucophores and iridophores is produced by their respective scattering and optical interference properties. Some species can rapidly change colour through mechanisms that trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatophores
Chromatophores are cells that produce color, of which many types are Biological pigment, pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contrast, have a class of cells called melanocytes for animal coloration, coloration. Chromatophores are largely responsible for generating skin and eye color, eye colour in ectothermic animals and are generated in the neural crest during embryonic development. Mature chromatophores are grouped into subclasses based on their colour under white light: xanthophores (yellow), erythrophores (red), iridophores (reflective / iridescence, iridescent), leucophores (white), melanophores (black/brown), and cyanophores (blue). While most chromatophores contain pigments that absorb specific wavelengths of light, the color of leucophores and iridophores is produced by their respective scattering and optical interference properties. Some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanophores
Chromatophores are cells that produce color, of which many types are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contrast, have a class of cells called melanocytes for coloration. Chromatophores are largely responsible for generating skin and eye colour in ectothermic animals and are generated in the neural crest during embryonic development. Mature chromatophores are grouped into subclasses based on their colour under white light: xanthophores (yellow), erythrophores (red), iridophores (reflective / iridescent), leucophores (white), melanophores (black/brown), and cyanophores (blue). While most chromatophores contain pigments that absorb specific wavelengths of light, the color of leucophores and iridophores is produced by their respective scattering and optical interference properties. Some species can rapidly change colour through mechanisms that tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shadow
A shadow is a dark area on a surface where light from a light source is blocked by an object. In contrast, shade occupies the three-dimensional volume behind an object with light in front of it. The cross-section of a shadow is a two-dimensional silhouette, or a reverse projection of the object blocking the light. Point and non-point light sources A point source of light casts only a simple shadow, called an "umbra". For a non-point or "extended" source of light, the shadow is divided into the umbra, penumbra, and antumbra. The wider the light source, the more blurred the shadow becomes. If two penumbras overlap, the shadows appear to attract and merge. This is known as the shadow blister effect. The outlines of the shadow zones can be found by tracing the rays of light emitted by the outermost regions of the extended light source. The umbra region does not receive any direct light from any part of the light source and is the darkest. A viewer located in the umbra regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
