parent_taxon eocaecilia
A fossorial ( from Latin " fossor ", " digger ") ___MASK50___ is one that is adapted to digging and life underground such as the badger , the naked mole - ___MASK76___ , or the mole salamanders . The Four Corners is a region of the United States consisting of the southwestern corner of Colorado , southeastern corner of Utah , northeastern corner of ___MASK17___ , and northwestern corner of New Mexico . The Four Corners area is named after the quadripoint where the boundaries of the four states meet , where the Four Corners Monument is located . It is the only location in the United States where four states meet . Most of the Four Corners region belongs to semi - autonomous Native American nations , the largest of which is the Navajo Nation , followed by Hopi , Ute , and Zuni tribal reserves and nations . The Four Corners region is part of a larger region known as the Colorado Plateau and is mostly rural , rugged , and arid . In addition to the monument , commonly visited areas within Four Corners include Monument Valley , Mesa Verde National Park , Chaco Canyon , and Canyon de Chelly National Monument . The most populous city in the Four Corners region is Farmington , New Mexico , followed by Durango , Colorado . ___MASK30___ , officially the Free and Sovereign State of ___MASK30___ , is one of 31 states that , with Mexico City , comprise the 32 federal entities of Mexico . It is divided into 72 municipalities ; the capital city is Hermosillo . ___MASK30___ is located in Northwest Mexico , bordered by the states of Chihuahua to the east , Baja California to the northwest and Sinaloa to the south . To the north , it shares the U . S . Mexico border with the states of ___MASK17___ and New Mexico , and on the west has a significant share of the coastline of the Gulf of California . New Mexico is a state located in the southwestern region of the United States of America . It was admitted to the union as the 47th state on January 6 , 1912 . It is usually considered one of the Mountain States . New Mexico is fifth by ___MASK57___ , the 36th - most populous , and the sixth - least densely populated of the 50 United States . Vertebrates comprise all species of animals within the subphylum ___MASK51___ ( chordates with backbones ). Vertebrates represent the overwhelming majority of the phylum Chordata , with currently about 64 , 000 species described . Vertebrates include the jawless fish and the jawed vertebrates , which include the cartilaginous fish ( sharks and rays ) and the bony fish . Kayenta is a U . S . census - designated place ( CDP ) which is part of the Navajo Nation and is in Navajo County , ___MASK17___ . The population was 5 , 189 at the 2010 census . Kayenta is located south of Monument Valley and contains a number of hotels and motels which service visitors to Monument Valley . Like other places on the Navajo Nation , it is illegal to serve alcohol . ___MASK17___ does not observe Daylight Time ; however , the Navajo reservation does . ___MASK34___ is the group of amphibians that includes the legless caecilians and all amphibians more closely related to them than to frogs or salamanders ( the " stem - caecilians "). The name derives from the Greek words  (" gymnos ", naked ) and  (" ophis ", snake ), as the caecilians were originally thought to be related to snakes . A habitat is an ecological or environmental ___MASK57___ that is inhabited by a particular species of animal , ___MASK67___ , or other type of organism . The term typically refers to the zone in which the organism lives and where it can find food , shelter , protection and mates for reproduction . It is the natural environment in which an organism lives , or the physical environment that surrounds a species population . ___MASK82___ is the most populous state in the United States and the third most extensive by area . Located on the western ( Pacific Ocean ) coast of the U . S ., ___MASK82___ is bordered by the other U . S . states of Oregon , Nevada , and ___MASK17___ and shares an international border with the Mexican state of Baja ___MASK82___ . The state capital is Sacramento . Los Angeles is ___MASK82___ ' s most populous city , and the country ' s second largest after New York City . The state also has the nation ' s most populous county , Los Angeles County , and its largest county by area , San Bernardino County . Mammals are any vertebrates within the class Mammalia ( from Latin " mamma " " breast "), a clade of endothermic amniotes distinguished from reptiles and birds by the possession of a neocortex ( a region of the brain ), hair , three middle ear bones and mammary glands . The sister group of mammals may be the extinct " Haldanodon ." The mammals represent the only living Synapsida , which together with the ___MASK6___ form the Amniota clade . The mammals consist of the Yinotheria including monotrema and the Theriiformes including the theria . Lizards are a widespread group of squamate reptiles , with over 6 , 000 species , ranging across all continents except Antarctica , as well as most oceanic island chains . The group , traditionally recognized as the suborder Lacertilia , is defined as all extant members of the ___MASK20___ ( reptiles with overlapping scales ) that are neither sphenodonts ( i . e ., tuatara ) nor snakes  they form an evolutionary grade . While the snakes are recognized as falling phylogenetically within the ___MASK85___ clade from which they evolved , the sphenodonts are the sister group to the squamates , the larger monophyletic group , which includes both the lizards and the snakes . Binomial nomenclature ( also called binominal nomenclature or binary nomenclature ) is a formal system of naming species of living things by giving each a name composed of two parts , both of which use Latin grammatical forms , although they can be based on words from other languages . Such a name is called a binomial name ( which may be shortened to just " binomial "), a binomen or a scientific name ; more informally it is also called a Latin name . The first part of the name identifies the genus to which the species belongs ; the second part identifies the species within the genus . For example , humans belong to the genus " ___MASK77___ " and within this genus to the species " ___MASK77___ sapiens ". The " formal " introduction of this system of naming species is credited to Carl Linnaeus , effectively beginning with his work " Species Plantarum " in 1753 . But Gaspard Bauhin , in as early as 1623 , had introduced in his book " Pinax theatri botanici " ( English , " Illustrated exposition of plants ") many names of genera that were later adopted by Linnaeus . In biology , an organism is any contiguous living system , such as an ___MASK50___ , ___MASK67___ , fungus , archaeon , or bacterium . All known types of organisms are capable of some degree of response to stimuli , reproduction , growth and development and homeostasis . An organism consists of one or more cells ; when it has one cell it is known as a unicellular organism ; and when it has more than one it is known as a multicellular organism . Most unicellular organisms are of microscopic scale and are thus loosely described as microorganisms . Humans are multicellular organisms composed of many trillions of cells grouped into specialized tissues and organs . Salamanders are a group of amphibians typically characterized by a ___MASK3___ - like appearance , with slender bodies , blunt snouts , short limbs projecting at right angles to the body , and the presence of a tail in both larvae and adults . All present - day salamander families are grouped together under the scientific name Urodela . Salamander diversity is most abundant in the Northern Hemisphere and most species are found in the Holarctic ecozone , with some species present in the Neotropical zone . A larva ( plural " larvae " ) is a distinct juvenile form many animals undergo before metamorphosis into adults . Animals with indirect development such as ___MASK12___ , amphibians , or cnidarians typically have a larval phase of their life cycle . Metamorphosis is a biological process by which an ___MASK50___ physically develops after birth or hatching , involving a conspicuous and relatively abrupt change in the ___MASK50___ ' s body structure through cell growth and differentiation . Some ___MASK12___ , fishes , amphibians , mollusks , crustaceans , cnidarians , echinoderms and tunicates undergo metamorphosis , which is often accompanied by a change of nutrition source or behavior . Animals that goes through metamorphosis are called metamorphoses . Animals can be divided into species that undergo complete metamorphosis (" holometaboly "), incomplete metamorphosis (" hemimetaboly "), or no metamorphosis (" ametaboly "). Baja ___MASK82___ , officially the Free and Sovereign State of Baja ___MASK82___ , is a state in Mexico . It is the northernmost and westernmost of the 31 states which , with Mexico City , comprises the 32 Federal Entities of Mexico . Before becoming a state in 1953 , the area was known as the North Territory of Baja ___MASK82___ (" El Territorio Norte de Baja ___MASK82___ "). It has an area of , or 3 . 57 % of the land mass of Mexico and comprises the northern half of the Baja ___MASK82___ Peninsula , north of the 28th parallel , plus oceanic Guadalupe Island . The mainland portion of the state is bordered on the west by the Pacific Ocean , on the east by ___MASK30___ , the U . S . State of ___MASK17___ , and the Gulf of ___MASK82___ ( also known as the " Sea of Cortez "), and on the south by Baja ___MASK82___ Sur . Its northern limit is the U . S . state of ___MASK82___ . Nevada ( Spanish for " snowy "; see pronunciations ) is a state in the Western , Mountain West , and Southwestern regions of the United States of America . Nevada is the 7th most extensive , the 34th most populous , and the 9th least densely populated of the 50 United States . Nearly three - quarters of Nevada ' s people live in Clark County , which contains the Las Vegas  Paradise metropolitan ___MASK57___ where three of the state ' s four largest incorporated cities are located . Nevada ' s capital is Carson City . Nevada is officially known as the " Silver State " because of the importance of silver to its history and economy . It is also known as the " Battle Born State ", because it achieved statehood during the Civil War ( the words " Battle Born " also appear on the state flag ); as the " Sage - brush State ", for the native ___MASK67___ of the same name ; and as the " Sage - hen State ". Nevada borders Oregon to the northwest , Idaho to the northeast , ___MASK82___ to the west , ___MASK17___ to the southeast and Utah to the east . The superclass ___MASK2___ ( Ancient Greek s tetrapods , " four - footed "), or the tetrapods , comprises the first four - limbed vertebrates and their descendants , including the living and extinct amphibians , birds , mammals , reptiles and some ancient , exclusively aquatic creatures such as the Acanthostega . Tetrapods evolved from the lobe - finned fishes around 390 million years ago in the middle Devonian Period , with modern tetrapod groups having appeared by the late Devonian , 367 . 5 million years ago . The specific aquatic ancestors of the tetrapods , and the process by which land colonization occurred , remain unclear , and are areas of active research and debate among palaeontologists at present . Eocaecilia is an extinct genus of caecilian ( limbless amphibian ) from the early Jurassic Kayenta Formation of ___MASK17___ , USA . One species is described , Eocaecilia micropodia . Eocaecilia shared some characteristics with salamanders and the now extinct Microsauria . It was of small size , about 15 cm in length . Unlike modern caecilians , which are legless , Eocaecilia possessed small legs , and while modern caecilians have poorly developed eyes and spend a lot of time under ground , Eocaecilia ' s eyes were somewhat better well - developed . Although the precise ancestry of Eocaecilia is debated ( and other caecilians by extension ) , it likely resided among the ancestral lepospondyl or temnospondyl amphibians of the Paleozoic and Mesozoic . Ecological indicators are used to communicate information about ecosystems and the impact ___MASK41___ activity has on ecosystems to groups such as the public or government policy makers . Ecosystems are complex and ecological indicators can help describe them in simpler terms that can be understood and used by non - scientists to make management decisions . For example , the number of different beetle taxa found in a field can be used as an ___MASK19___ of biodiversity . A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water and excretes carbon dioxide . The gills of some species , such as ___MASK9___ crabs , have adapted to allow respiration on land provided they are kept moist . The microscopic structure of a gill presents a large surface area to the external environment . " Kayenta , ___MASK17___ is a settlement in the Navajo reservation ." Caecilians ( New Latin , " blind ones ") are a group of limbless , serpentine amphibians . They mostly live hidden in the ground , making them the least familiar order of amphibians . All modern caecilians and their closest fossil relatives are grouped as a clade , ___MASK70___ , within the larger group ___MASK34___ , which also includes more primitive extinct caecilian - like amphibians . Caecilians are mostly distributed in the tropics of South and Central America , Africa , and southern Asia . The diets of caecilians are not well known . Utah ( or ) is a state in the western United States . It became the 45th state admitted to the U . S . on January 4 , 1896 . Utah is the 13th - largest by ___MASK57___ , 31st - most - populous , and 10th - least - densely populated of the 50 United States . Utah has a population of more than 3 million ( Census estimate for July 1 , 2016 ), approximately 80 % of whom live along the Wasatch Front , centering on the state capital Salt Lake City . Utah is bordered by Colorado to the east , Wyoming to the northeast , Idaho to the north , ___MASK17___ to the south , and Nevada to the west . It also touches a corner of New Mexico in the southeast . A genus ( genera ) is a taxonomic rank used in the biological classification of living and fossil organisms in biology . In the hierarchy of biological classification , genus comes above species and below family . In binomial nomenclature , the genus name forms the first part of the binomial species name for each species within the genus . Mexico (, modern Nahuatl ), officially the United Mexican States , is a federal republic in the southern half of North America . It is bordered to the north by the United States ; to the south and west by the Pacific Ocean ; to the southeast by Guatemala , Belize , and the Caribbean Sea ; and to the east by the Gulf of Mexico . Covering almost two million square kilometers ( over 760 , 000 sq mi ), Mexico is the sixth largest country in the Americas by total ___MASK57___ and the 13th largest independent nation in the world . With an estimated population of over 120 million , it is the eleventh most populous country and the most populous Spanish - speaking country in the world while being the second most populous country in Latin America . Mexico is a federation comprising 31 states and a federal district that is also its capital and most populous city . Other metropolises include Guadalajara , Monterrey , Puebla , Toluca , Tijuana and León . Amphibians are ectothermic , tetrapod vertebrates of the class ___MASK84___ . Modern amphibians are all ___MASK32___ . They inhabit a wide variety of habitats , with most species living within terrestrial , fossorial , arboreal or freshwater aquatic ecosystems . Thus amphibians typically start out as larvae living in water , but some species have developed behavioural adaptations to bypass this . The young generally undergo metamorphosis from larva with gills to an adult air - breathing form with lungs . Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin . They are superficially similar to lizards but , along with mammals and birds , reptiles are amniotes and do not require water bodies in which to breed . With their complex reproductive needs and permeable skins , amphibians are often ecological indicators ; in recent decades there has been a dramatic decline in amphibian populations for many species around the globe . ___MASK17___ ( O ' odham : " Al onak " [ ai onak ]) is a state in the southwestern region of the United States . It is also part of the Western United States and the Mountain West states . It is the sixth largest and the 14th most populous of the 50 states . Its capital and largest city is Phoenix . ___MASK17___ is one of the Four Corners states . It has borders with New Mexico , Utah , Nevada , California , and Mexico , and one point in common with the southwestern corner of Colorado . ___MASK17___ ' s border with Mexico is 389 miles ( 626 km ) long , on the northern border of the Mexican states of Sonora and Baja California . The ___MASK32___ are a group of tetrapods that includes all modern amphibians . Lissamphibians consist of three living groups : the ___MASK90___ ( frogs , toads , and their extinct relatives ), the Caudata ( salamanders , newts , and their extinct relatives ), and the ___MASK34___ ( the limbless caecilians and their extinct relatives ). A fourth group , the Allocaudata , was moderately successful , spanning 160 million years from the Middle Jurassic to the Early Pliocene , but became extinct 2 . 5 million years ago .