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| Testudines, Chelonia |
Turtles are reptiles of the order Testudines (all living turtles belong to the crown group Chelonia), most of whose body is shielded by a special bony or cartilagenous shell developed from their ribs. The term turtle is usually used for the aquatic species, though aquatic fresh water turtles are also called terrapins. The term is sometimes used (esp. in North America) to refer to all members of the order, including tortoises, which are predominantly land-based. The order of Testudines includes both extant (living) and extinct species. About 300 species are alive today. Some species of turtles are highly endangered.
All turtles have a protective shell around their bodies. The top part of the shell is called the carapace, the bottom is called the plastron, and the two are connected by a bridge. Some are known to be able to breathe through their rectums as well. Reference the Rheodytes leukops species.
Sea turtles grow to large sizes and live in the oceans in the temperate and tropical regions of Earth. Pond turtles (terrapins) are usually much smaller, while some land terrapins (tortoises) are as large as sea turtles. The sizes of turtles vary from a few centimetres (forest and jungle species) to two metres (the leatherback turtle and the Galapagos tortoise).
Turtles generally live a long time; some individuals are known to have lived longer than 150 years. The oldest tortoise on record is Tui Malila, known to have lived at least 188 years.
Sea turtles lay their eggs on dry sandy beaches. The eggs of the largest species are spherical, while the eggs of the rest are elongated. Their albumen is white and will not coagulate when cooked because of the protein it contains which is different to that of bird eggs. Turtle eggs prepared to eat consist mainly of yolk. In some species, temperature of the egg during development determines whether an egg develops into a male or a female: a higher temperature causes a female, a lower temperature causes a male.
Although they spend large proportions of their lives underwater, turtles are air-breathing reptiles, and must surface at regular intervals to refill their lungs with fresh air. However, aquatic respiration in Australian freshwater turtles is currently being studied. Some species have large cloacal cavities lined with many finger-like projections. These projections, called "papillae", have a rich blood supply, and increase the surface area of the cloaca. The turtles can take up dissolved oxygen from the water through these papillae, in much the same way that fish use gills.
Turtles have a gelatinous substance in their upper and lower shell, called calipash and calipee respectively, the calipash being of a dull greenish and the calipee of a light yellow color.
The first turtles are believed to have existed in the era of the dinosaurs, 200 million years ago. Their exact ancestry is disputed. It was believed that they are the only surviving branch of the ancient clade Anapsida, which includes groups such as procolophonoids, millerettids, protorothyrids and pareiasaurs. All Anapsid skulls lack a temporal opening, while all other extant amniotes have temporal openings (although in mammals the hole has become the zygoid arch). Most anapsids became extinct in the late Permian period, except procolophonoids and possibly the precursors of the testudines (turtles).
However, it was recently suggested that the Anapsid-like turtle skull may be due to convergent evolution rather than to anapsid descent. More recent phylogenetic studies with this in mind placed turtles firmly within diapsids, slightly closer to Squamata than to Archosauria. All molecular studies have strongly upheld this new phylogeny, though some place turtles closer to Archosauria. Re-analysis of prior phylogenies suggests that they classified turtles as anapsids both because they assumed this classification (most of them studying what sort of anapsid turtles are) and because they did not sample fossil and extant taxa were broadly enough for constructing the cladogram. While the issue is far from resolved, most scientists now lean towards a Diapsid origin for turtles.
Suborder Paracryptodira (extinct)
Suborder Cryptodira
Suborder Pleurodira
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Suborder Pleurodira. The numeric character references in HTML and XML are "W" and "w" for upper and lower case respectively. Suborder Cryptodira. The EBCDIC code for capital W is 230 and for lowercase w is 166. Suborder Paracryptodira (extinct) Re-analysis of prior phylogenies suggests that they classified turtles as anapsids both because they assumed this classification (most of them studying what sort of anapsid turtles are) and because they did not sample fossil and extant taxa were broadly enough for constructing the cladogram. Bush's nickname of "Dubya". All molecular studies have strongly upheld this new phylogeny, though some place turtles closer to Archosauria. In the Texas dialect of American English, the name is often condensed to two syllables rather than three, resulting in George W. More recent phylogenetic studies with this in mind placed turtles firmly within diapsids, slightly closer to Squamata than to Archosauria. A few speakers therefore shorten the name "double u" into "dub" only, although this is rather rare and nonstandard; for example, University of Washington is known colloquially as "U Dub". However, it was recently suggested that the Anapsid-like turtle skull may be due to convergent evolution rather than to anapsid descent. This gives the nine-syllable initialism www the irony of being an abbreviation that takes more syllables to say than the unabbreviated form. Most anapsids became extinct in the late Permian period, except procolophonoids and possibly the precursors of the testudines (turtles). "Double U" is the only English letter name with more than one syllable. All Anapsid skulls lack a temporal opening, while all other extant amniotes have temporal openings (although in mammals the hole has become the zygoid arch). The equivalent representation of the [w] sound in the Cyrillic alphabet is Ў, a letter unique to the Belarusian language. It was believed that they are the only surviving branch of the ancient clade Anapsida, which includes groups such as procolophonoids, millerettids, protorothyrids and pareiasaurs. See more (in Hebrew). Their exact ancestry is disputed. For example many Israelis say "Hollyvud" rather than "Hollywood" or "Darvin" rather than "Darwin". The first turtles are believed to have existed in the era of the dinosaurs, 200 million years ago. In Hebrew the same letter, waw or vav is used to spell both [w] and [v], which can make problems in some cases. Turtles have a gelatinous substance in their upper and lower shell, called calipash and calipee respectively, the calipash being of a dull greenish and the calipee of a light yellow color. When a spelling for the [w] sound in a native word is needed, a spelling from the native alphabet, such as U or OU, can be used instead. The turtles can take up dissolved oxygen from the water through these papillae, in much the same way that fish use gills. In the alphabets of modern Romance languages, it is not used either, except in foreign names and words recently borrowed (le week-end, il watt, el kiwi). These projections, called "papillae", have a rich blood supply, and increase the surface area of the cloaca. It is however recognized and maintained in names, like "William". Some species have large cloacal cavities lined with many finger-like projections. In the Swedish and Finnish alphabets, "W" is seen as a variant of "V" and not a separate letter. However, aquatic respiration in Australian freshwater turtles is currently being studied. There are only four major European languages that use W in native words: English, German, Polish, and Dutch. Although they spend large proportions of their lives underwater, turtles are air-breathing reptiles, and must surface at regular intervals to refill their lungs with fresh air. In Dutch, W is a labiodental approximant (with the exception of words with EEUW, which have /eːw/), or other diphthongs containing -UW. In some species, temperature of the egg during development determines whether an egg develops into a male or a female: a higher temperature causes a female, a lower temperature causes a male. In German—as in Romance—the phoneme [w] was lost; this is why German W represents [v] rather than [w]. Turtle eggs prepared to eat consist mainly of yolk. The Latin [w] sound developed into Romance [v]; therefore V no longer adequately represented Germanic [w]. Their albumen is white and will not coagulate when cooked because of the protein it contains which is different to that of bird eggs. This digraph was not extensively used, the sound usually being represented instead by the runic wynn (Ƿ), but W gained popularity after the Norman Conquest, and by 1300 it had taken wynn's place in common use. The eggs of the largest species are spherical, while the eggs of the rest are elongated. The earliest form of the letter W was a doubled V used in the 7th century by the earliest writers of Old English; it is from this <uu> digraph that the modern name "double U" comes. Sea turtles lay their eggs on dry sandy beaches. Its name in English is double-u. The oldest tortoise on record is Tui Malila, known to have lived at least 188 years. W is the twenty-third letter of the modern Latin alphabet. Turtles generally live a long time; some individuals are known to have lived longer than 150 years. w or w/ is an abbreviation for the word "with". The sizes of turtles vary from a few centimetres (forest and jungle species) to two metres (the leatherback turtle and the Galapagos tortoise). In Final Fantasy XI, Japanese players use "w" to be used in the terms of "lol", also constantly used by English players as well. Pond turtles (terrapins) are usually much smaller, while some land terrapins (tortoises) are as large as sea turtles. In NetHack, "w" is the command to wield (or unwield) a weapon, and "W" is the command to wear armor. Sea turtles grow to large sizes and live in the oceans in the temperate and tropical regions of Earth. W is the symbol for Wario, a Nintendo character. Reference the Rheodytes leukops species. In computing and video games,
All turtles have a protective shell around their bodies. W is the name of a Canadian specialty service dedicated to women's issues, formerly called WTN; see W Network. . In television,
The order of Testudines includes both extant (living) and extinct species. W Hotels is an international chain of boutique hotels in urban centers. in North America) to refer to all members of the order, including tortoises, which are predominantly land-based. In publishing, W is the name of an American fashion magazine; see W (magazine). The term is sometimes used (esp. In weather forecasting, geography, and weather vanes, W stands for west, one of the four cardinal directions. The term turtle is usually used for the aquatic species, though aquatic fresh water turtles are also called terrapins. In the United Kingdom, W stands for West London. Turtles are reptiles of the order Testudines (all living turtles belong to the crown group Chelonia), most of whose body is shielded by a special bony or cartilagenous shell developed from their ribs. As the first letter of a postal code,
Superfamily Trionychoidea. In politics, W is a nickname of American President George W. Superfamily Testudinoidea. W is a kind of a subatomic particle, the W boson. W is often the variable for energy or work, measured in joules. In physics,
W is the symbol for the watt, the SI derived unit for power. In the SI system,
There is also a J-Pop act called W (Double You). In Japan, W is commonly used in slang and advertising to represent the English loanword "double". In Italy, W (which does not appear in the Italian alphabet) stands for Viva ("long live"). In the International Phonetic Alphabet, [w] represents a labial-velar approximant. In population genetics, w is the symbol for fitness. WZ denotes female in the WZ sex-determination system. In genetics W denotes the W chromosome.
W is the name of a graphical windowing system for Unix platforms; see W Window System. w is a command on Unix systems that displays information on users who are currently logged in. This is because in some programs (e.g., many Unix shells) the keystroke control-W is used to delete the previous word. ^W is often used jokingly to indicate the intended deletion of the previous word (see also H). In computing,
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