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64-411: Tortoises ( / ˈ t ɔːr t ə s . ɪ z / TOR -təs-iz ) are reptiles of the family Testudinidae of the order Testudines ( Latin for "tortoise"). Like other turtles , tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like other members of the suborder Cryptodira , they retract their necks and heads directly backward into
128-562: A clade ( monophyletic group) including birds, though the precise definition of this clade varies between authors. Others prioritize the clade Sauropsida , which typically refers to all amniotes more closely related to modern reptiles than to mammals . The earliest known proto-reptiles originated from the Carboniferous period, having evolved from advanced reptiliomorph tetrapods which became increasingly adapted to life on dry land. The earliest known eureptile ("true reptile")
192-447: A temnospondyl ). A series of footprints from the fossil strata of Nova Scotia dated to 315 Ma show typical reptilian toes and imprints of scales. These tracks are attributed to Hylonomus , the oldest unquestionable reptile known. It was a small, lizard-like animal, about 20 to 30 centimetres (7.9 to 11.8 in) long, with numerous sharp teeth indicating an insectivorous diet. Other examples include Westlothiana (for
256-411: A cloacal kiss in most birds. Birds that mate using this method touch their cloacae together, in some species for only a few seconds, sufficient time for sperm to be transferred from the male to the female. For palaeognaths and waterfowl , the males do not use the cloaca for reproduction, but have a phallus . One study has looked into birds that use their cloaca for cooling. Among falconers ,
320-639: A female spur-thighed tortoise , lived to be about 165 years old. For 38 years, she was carried as a mascot aboard various ships in Britain's Royal Navy . Then in 1892, at age 53, she retired to the grounds of Powderham Castle in Devon . Up to the time of her death in 2004, she was believed to be the United Kingdom's oldest resident. Jonathan , a Seychelles giant tortoise living on the island of St Helena , may be as old as 192 years. DNA analysis of
384-461: A few exceptions noted below, mammals have no cloaca. Even in the marsupials that have one, the cloaca is partially subdivided into separate regions for the anus and urethra . The monotremes (egg-laying mammals) possess a true cloaca. In marsupials , the genital tract is separate from the anus, but a trace of the original cloaca does remain externally. This is one of the features of marsupials (and monotremes) that suggest their basal nature, as
448-410: A longer, more protruding neck plate than their female counterparts, while in others, the claws are longer on the females. The male plastron is curved inwards to aid reproduction. The easiest way to determine the sex of a tortoise is to look at the tail. The females, as a general rule, have smaller tails, dropped down, whereas the males have much longer tails which are usually pulled up and to the side of
512-448: A more specific term for slow-moving terrestrial species. General American usage agrees; turtle is often a general term; tortoise is used only in reference to terrestrial turtles or, more narrowly, only those members of Testudinidae, the family of modern land tortoises; and terrapin may refer to turtles that are small and live in fresh and brackish water, in particular the diamondback terrapin ( Malaclemys terrapin ). In America, for example,
576-495: A section of the clade Amniota : The section that is left after the Mammalia and Aves have been hived off. It cannot be defined by synapomorphies , as is the proper way. Instead, it is defined by a combination of the features it has and the features it lacks: reptiles are the amniotes that lack fur or feathers. At best, the cladists suggest, we could say that the traditional Reptilia are 'non-avian, non-mammalian amniotes'. Despite
640-415: A source of nutrition for the first three to seven days until they have the strength and mobility to find food. Juvenile tortoises often require a different balance of nutrients than adults, so may eat foods which a more mature tortoise would not. For example, the young of a strictly herbivorous species commonly will consume worms or insect larvae for additional protein. The number of concentric rings on
704-569: A tiny gecko, Sphaerodactylus ariasae , which can grow up to 17 mm (0.7 in) to the saltwater crocodile , Crocodylus porosus , which can reach over 6 m (19.7 ft) in length and weigh over 1,000 kg (2,200 lb). In the 13th century, the category of reptile was recognized in Europe as consisting of a miscellany of egg-laying creatures, including "snakes, various fantastic monsters, lizards, assorted amphibians, and worms", as recorded by Beauvais in his Mirror of Nature . In
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#1732794005274768-435: Is detrimental in herbivorous species, and has been associated with shell deformities and other medical problems. Different tortoise species vary greatly in their nutritional requirements. Communication in tortoises is different from many other reptiles. Because they are restricted by their shell and short limbs, visual communication is not a strong form of communication in tortoises. Tortoises use olfactory cues to determine
832-479: Is equivalent to the more common definition of Sauropsida, which Modesto and Anderson synonymized with Reptilia, since the latter is better known and more frequently used. Unlike most previous definitions of Reptilia, however, Modesto and Anderson's definition includes birds, as they are within the clade that includes both lizards and crocodiles. General classification of extinct and living reptiles, focusing on major groups. The cladogram presented here illustrates
896-577: Is the rear orifice that serves as the only opening for the digestive , reproductive , and urinary tracts (if present) of many vertebrate animals. All amphibians , reptiles , birds , and a few mammals ( monotremes , afrosoricids , and marsupial moles ) have this orifice, from which they excrete both urine and feces ; this is in contrast to most placental mammals, which have two or three separate orifices for evacuation and reproduction. Excretory openings with analogous purpose in some invertebrates are also sometimes called cloacae. Mating through
960-627: Is used to refer to a larger group of semiaquatic turtles than the restricted meaning in America. Australian usage is different from both American and British usage. Land tortoises are not native to Australia, and traditionally freshwater turtles have been called "tortoises" in Australia. Some Australian experts disapprove of this usage—believing that the term tortoises is "better confined to purely terrestrial animals with very different habits and needs, none of which are found in this country"—and promote
1024-499: Is where reproductive activity occurs. Some turtles , especially those specialized in diving, are highly reliant on cloacal respiration during dives. They accomplish this by having a pair of accessory air bladders connected to the cloaca, which can absorb oxygen from the water. Sea cucumbers use cloacal respiration. The constant flow of water through it has allowed various fish , polychaete worms and even crabs to specialize to take advantage of it while living protected inside
1088-1050: The Bahamas , the Greater Antilles (including Cuba and Hispaniola ), the Lesser Antilles , the Canary Islands , Malta , the Seychelles , the Mascarene Islands (including Mauritius and Reunion ), and Madagascar . Most of these tortoises were wiped out by human arrival. Many of these giant tortoises are not closely related (belonging to different genera such as Megalochelys , Chelonoidis , Centrochelys , Aldabrachelys , Cylindraspis , and Hesperotestudo ), but are thought to have independently evolved large body size through convergent evolution . Giant tortoises are notably absent from Australasia and many south Pacific islands, but
1152-781: The Galapagos giant tortoise and the Aldabra giant tortoise . They are usually diurnal animals with tendencies to be crepuscular depending on the ambient temperatures. They are generally reclusive animals. Tortoises are the longest-living land animals in the world, although the longest-living species of tortoise is a matter of debate. Galápagos tortoises are noted to live over 150 years, but an Aldabra giant tortoise named Adwaita may have lived an estimated 255 years. In general, most tortoise species can live 80–150 years. Tortoises are placid and slow-moving, with an average walking speed of 0.2–0.5 km/h. Differences exist in usage of
1216-861: 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 ( / r ɛ p ˈ t ɪ l i ə / rep- TIL -ee-ə ), 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
1280-455: The amniotes from which mammals evolved had a cloaca, and probably so did the earliest mammals . Unlike other marsupials, marsupial moles have a true cloaca. This fact has been used to argue that they are not marsupials. Most adult placental mammals have no cloaca. In the embryo, the embryonic cloaca divides into a posterior region that becomes part of the anus, and an anterior region that develops depending on sex: in males, it forms
1344-418: The amniotic egg . The terms Sauropsida ("lizard faces") and Theropsida ("beast faces") were used again in 1916 by E.S. Goodrich to distinguish between lizards, birds, and their relatives on the one hand (Sauropsida) and mammals and their extinct relatives (Theropsida) on the other. Goodrich supported this division by the nature of the hearts and blood vessels in each group, and other features, such as
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#17327940052741408-405: The carapace and plastron . The plastron of a female tortoise often has a noticeable V-shaped notch below the tail which facilitates passing the eggs. Upon completion of the incubation period, a fully formed hatchling uses an egg tooth to break out of its shell. It digs to the surface of the nest and begins a life of survival on its own. They are hatched with an embryonic egg sac which serves as
1472-422: The development of the urinary and reproductive organs . However, a few human congenital disorders result in persons being born with a cloaca, including persistent cloaca and sirenomelia (mermaid syndrome). In reptiles, the cloaca consists of the urodeum , proctodeum , and coprodeum . Some species have modified cloacae for increased gas exchange (see reptile respiration and reptile reproduction ). This
1536-459: The genomes of the long-lived tortoises, Lonesome George , the iconic last member of Chelonoidis abingdonii , and the Aldabra giant tortoise Aldabrachelys gigantea led to the detection of lineage-specific variants affecting DNA repair genes that might contribute to their long lifespan. Many species of tortoises are sexually dimorphic , though the differences between males and females vary from species to species. In some species, males have
1600-402: The penile urethra , while in females, it develops into the vestibule or urogenital sinus that receives the urethra and vagina. However, some placental mammals retain a cloaca as adults: those are members of the order Afrosoricida (small mammals native to Africa) as well as some shrews . Being placental animals, humans have an embryonic cloaca which divides into separate tracts during
1664-1741: The "family tree" of reptiles, and follows a simplified version of the relationships found by M.S. Lee, in 2013. All genetic studies have supported the hypothesis that turtles are diapsids; some have placed turtles within Archosauromorpha, though a few have recovered turtles as Lepidosauromorpha instead. The cladogram below used a combination of genetic (molecular) and fossil (morphological) data to obtain its results. Synapsida ( mammals and their extinct relatives) [REDACTED] † Millerettidae [REDACTED] † Eunotosaurus † Lanthanosuchidae [REDACTED] † Pareiasauromorpha [REDACTED] † Procolophonoidea [REDACTED] † Captorhinidae [REDACTED] † Paleothyris † Araeoscelidia [REDACTED] † Claudiosaurus [REDACTED] † Younginiformes [REDACTED] † Kuehneosauridae [REDACTED] Rhynchocephalia ( tuatara and their extinct relatives) [REDACTED] Squamata ( lizards and snakes ) [REDACTED] [REDACTED] † Eosauropterygia [REDACTED] † Placodontia [REDACTED] † Sinosaurosphargis † Odontochelys † Proganochelys Testudines ( turtles ) [REDACTED] † Choristodera [REDACTED] † Prolacertiformes [REDACTED] † Rhynchosauria [REDACTED] † Trilophosaurus [REDACTED] Archosauriformes ( crocodiles , birds , dinosaurs and extinct relatives) [REDACTED] [REDACTED] The placement of turtles has historically been highly variable. Classically, turtles were considered to be related to
1728-418: The 17th century, Francesco Redi performed an experiment that involved removing the brain of a land tortoise, which then proceeded to live six months. Freshwater tortoises, when subjected to the same experiment, continued similarly, but did not live so long. Redi also cut the head off a tortoise entirely, and it lived for 23 days. Tortoises are found from southern North America to southern South America, around
1792-453: The 18th century, the reptiles were, from the outset of classification, grouped with the amphibians . Linnaeus , working from species-poor Sweden , where the common adder and grass snake are often found hunting in water, included all reptiles and amphibians in class "III – Amphibia" in his Systema Naturæ . The terms reptile and amphibian were largely interchangeable, reptile (from Latin repere , 'to creep') being preferred by
1856-484: The French. J.N. Laurenti was the first to formally use the term Reptilia for an expanded selection of reptiles and amphibians basically similar to that of Linnaeus. Today, the two groups are still commonly treated under the single heading herpetology . It was not until the beginning of the 19th century that it became clear that reptiles and amphibians are, in fact, quite different animals, and P.A. Latreille erected
1920-491: The Mediterranean basin, across Eurasia to Southeast Asia, in sub-Saharan Africa, Madagascar, and some Pacific islands. They are absent from Australasia . They live in diverse habitats, including deserts, arid grasslands, and scrub to wet evergreen forests, and from sea level to mountains. Most species, however, occupy semiarid habitats. Many large islands are or were characterized by species of giant tortoises . Part of
1984-657: The anapsid condition has been found to occur so variably among unrelated groups that it is not now considered a useful distinction. By the early 21st century, vertebrate paleontologists were beginning to adopt phylogenetic taxonomy, in which all groups are defined in such a way as to be monophyletic ; that is, groups which include all descendants of a particular ancestor. The reptiles as historically defined are paraphyletic , since they exclude both birds and mammals. These respectively evolved from dinosaurs and from early therapsids, both of which were traditionally called "reptiles". Birds are more closely related to crocodilians than
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2048-419: The average incubation period are between 100 and 160.0 days. Egg-laying typically occurs at night, after which the mother tortoise covers her clutch with sand, soil, and organic material. The eggs are left unattended, and depending on the species, take from 60 to 120 days to incubate. The size of the egg depends on the size of the mother and can be estimated by examining the width of the cloacal opening between
2112-487: The carapace, much like the cross-section of a tree , can sometimes give a clue to how old the animal is, but, since the growth depends highly on the accessibility of food and water, a tortoise that has access to plenty of forage (or is regularly fed by its owner) with no seasonal variation will have no noticeable rings. Moreover, some tortoises grow more than one ring per season, and in some others, due to wear, some rings are no longer visible. Tortoises generally have one of
2176-605: The care of the Tongan royal family until its death by natural causes on May 19, 1965, at the age of 188. The Alipore Zoo in India was the home to Adwaita , which zoo officials claimed was the oldest living animal until its death on March 23, 2006. Adwaita (also spelled Addwaita) was an Aldabra giant tortoise brought to India by Lord Wellesley, who handed it over to the Alipur Zoological Gardens in 1875 when
2240-421: The class Batracia (1825) for the latter, dividing the tetrapods into the four familiar classes of reptiles, amphibians, birds, and mammals. The British anatomist T.H. Huxley made Latreille's definition popular and, together with Richard Owen , expanded Reptilia to include the various fossil " antediluvian monsters", including dinosaurs and the mammal-like ( synapsid ) Dicynodon he helped describe. This
2304-482: The cloaca is called cloacal copulation and cloacal kissing. The cloacal region is also often associated with a secretory organ, the cloacal gland, which has been implicated in the scent-marking behavior of some reptiles, marsupials, amphibians, and monotremes . The word is from the Latin verb cluo , "(I) cleanse", thus the noun cloaca , " sewer , drain". Birds reproduce using their cloaca; this occurs during
2368-444: The common terms turtle , tortoise, and terrapin , depending on the variety of English being used; usage is inconsistent and contradictory. These terms are common names and do not reflect precise biological or taxonomic distinctions. The American Society of Ichthyologists and Herpetologists uses "turtle" to describe all species of the order Testudines, regardless of whether they are land-dwelling or sea-dwelling, and uses "tortoise" as
2432-753: The distantly related meiolaniid turtles are thought to have filled the same niche. Giant tortoises are also known from the Oligocene - Pliocene of mainland North America , South America , Europe , Asia , and Africa , but are all now extinct, which is also attributed to human activity. Tortoises are generally considered to be strict herbivores , feeding on grasses, weeds, leafy greens, flowers, and some fruits. However, hunting and eating of birds has been observed on occasion. Pet tortoises typically require diets based on wild grasses, weeds, leafy greens and certain flowers. Certain species consume worms or insects and carrion in their normal habitats. Too much protein
2496-503: The dominant large herbivores on many islands due to their low metabolic rate and reduced need for fresh water compared to mammals. Today there are only two living species of giant tortoises, the Aldabra giant tortoise on Aldabra Atoll and the dozen subspecies of Galapagos giant tortoise found on the Galapagos Islands . However, until recently giant tortoises could be found on nearly every major island group, including
2560-554: The early proposals for replacing the paraphyletic Reptilia with a monophyletic Sauropsida , which includes birds, that term was never adopted widely or, when it was, was not applied consistently. When Sauropsida was used, it often had the same content or even the same definition as Reptilia. In 1988, Jacques Gauthier proposed a cladistic definition of Reptilia as a monophyletic node-based crown group containing turtles, lizards and snakes, crocodilians, and birds, their common ancestor and all its descendants. While Gauthier's definition
2624-453: The fetus develops within the mother, using a (non-mammalian) placenta rather than contained in an eggshell . As amniotes, reptile eggs are surrounded by membranes for protection and transport, which adapt them to reproduction on dry land. Many of the viviparous species feed their fetuses through various forms of placenta analogous to those of mammals , with some providing initial care for their hatchlings. Extant reptiles range in size from
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2688-466: The hypothesis that turtles belong to a separate clade within Sauropsida , outside the saurian clade altogether. The origin of the reptiles lies about 310–320 million years ago, in the steaming swamps of the late Carboniferous period, when the first reptiles evolved from advanced reptiliomorphs . The oldest known animal that may have been an amniote is Casineria (though it may have been
2752-508: The late 19th century, a number of definitions of Reptilia were offered. The biological traits listed by Lydekker in 1896, for example, include a single occipital condyle , a jaw joint formed by the quadrate and articular bones, and certain characteristics of the vertebrae . The animals singled out by these formulations, the amniotes other than the mammals and the birds, are still those considered reptiles today. The synapsid/sauropsid division supplemented another approach, one that split
2816-508: The latter are to the rest of extant reptiles. Colin Tudge wrote: Mammals are a clade , and therefore the cladists are happy to acknowledge the traditional taxon Mammalia ; and birds, too, are a clade, universally ascribed to the formal taxon Aves . Mammalia and Aves are, in fact, subclades within the grand clade of the Amniota. But the traditional class Reptilia is not a clade. It is just
2880-796: The living reptiles, there are many diverse groups that are now extinct , in some cases due to mass extinction events . In particular, the Cretaceous–Paleogene extinction event wiped out the pterosaurs , plesiosaurs , and all non-avian dinosaurs alongside many species of crocodyliforms and squamates (e.g., mosasaurs ). Modern non-bird reptiles inhabit all the continents except Antarctica. Reptiles are tetrapod vertebrates , creatures that either have four limbs or, like snakes, are descended from four-limbed ancestors. Unlike amphibians , reptiles do not have an aquatic larval stage. Most reptiles are oviparous , although several species of squamates are viviparous , as were some extinct aquatic clades –
2944-551: The longest lifespans of any animal, and some individuals are known to have lived longer than 150 years. Because of this, they symbolize longevity in some cultures, such as Chinese culture . The oldest tortoise ever recorded, and one of the oldest individual animals ever recorded, was Tu'i Malila , which was presented to the Tongan royal family by the British explorer James Cook shortly after its birth in 1777. Tu'i Malila remained in
3008-414: The members of the genus Terrapene dwell on land, yet are referred to as box turtles rather than tortoises. British usage, by contrast, tends not to use "turtle" as a generic term for all members of the order, and also applies the term "tortoises" broadly to all land-dwelling members of the order Testudines, regardless of whether they are actually members of the family Testudinidae. In Britain, terrapin
3072-484: The moment considered a reptiliomorph rather than a true amniote ) and Paleothyris , both of similar build and presumably similar habit. However, microsaurs have been at times considered true reptiles, so an earlier origin is possible. Cloacal A cloaca ( / k l oʊ ˈ eɪ k ə / kloh- AY -kə ), pl. : cloacae ( / k l oʊ ˈ eɪ s i / kloh- AY -see or / k l oʊ ˈ eɪ k i / kloh- AY -kee ), or vent ,
3136-422: The other euryapsids, and given the older name Parapsida. Parapsida was later discarded as a group for the most part (ichthyosaurs being classified as incertae sedis or with Euryapsida). However, four (or three if Euryapsida is merged into Diapsida) subclasses remained more or less universal for non-specialist work throughout the 20th century. It has largely been abandoned by recent researchers: In particular,
3200-416: The primitive anapsid reptiles. Molecular work has usually placed turtles within the diapsids. As of 2013, three turtle genomes have been sequenced. The results place turtles as a sister clade to the archosaurs , the group that includes crocodiles, non-avian dinosaurs, and birds. However, in their comparative analysis of the timing of organogenesis , Werneburg and Sánchez-Villagra (2009) found support for
3264-433: The rear shell. The brain of a tortoise is extremely small. Red-footed tortoises, from Central and South America, do not have an area in the brain called the hippocampus , which relates to emotion, learning, memory and spatial navigation. Studies have shown that red-footed tortoises may rely on an area of the brain called the medial cortex for emotional actions, an area that humans use for actions such as decision making. In
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#17327940052743328-402: The reason for this is that tortoises are good at oceanic dispersal . Despite being unable to swim, tortoises are able to survive long periods adrift at sea because they can survive months without food or fresh water. Tortoises have been known to survive oceanic dispersals of more than 740 km. Once on islands tortoises faced few predators or competitors and could grow to large sizes and become
3392-438: The reptiles into four subclasses based on the number and position of temporal fenestrae , openings in the sides of the skull behind the eyes. This classification was initiated by Henry Fairfield Osborn and elaborated and made popular by Romer 's classic Vertebrate Paleontology . Those four subclasses were: The composition of Euryapsida was uncertain. Ichthyosaurs were, at times, considered to have arisen independently of
3456-971: The sex of other tortoises so that they can find a potential mate. Tactile communication is important in tortoises during combat and courtship. In both combat and courtship, tortoises use ramming to communicate with other individuals. This species list largely follows Turtle Taxonomy Working Group (2021) and the Turtle Extinctions Working Group (2015). Family Testudinidae Batsch 1788 A molecular phylogeny of tortoises, following Le et al. (2006: 525): Ergilemys Manouria Gopherus Indotestudo Testudo Malacochersus Centrochelys sulcata Geochelone platynota Geochelone elegans Chersina Homopus Stigmochelys Psammobates Aldabrachelys Pyxis Astrochelys radiata Astrochelys yniphora Kinixys Chelonoidis A separate phylogeny via mtDNA analysis
3520-514: The shell to protect them. Tortoises can vary in size with some species, such as the Galápagos giant tortoise , growing to more than 1.2 metres (3.9 ft) in length, whereas others like the Speckled cape tortoise have shells that measure only 6.8 centimetres (2.7 in) long. Several lineages of tortoises have independently evolved very large body sizes in excess of 100 kg, including
3584-789: The structure of the forebrain. According to Goodrich, both lineages evolved from an earlier stem group, Protosauria ("first lizards") in which he included some animals today considered reptile-like amphibians , as well as early reptiles. In 1956, D.M.S. Watson observed that the first two groups diverged very early in reptilian history, so he divided Goodrich's Protosauria between them. He also reinterpreted Sauropsida and Theropsida to exclude birds and mammals, respectively. Thus his Sauropsida included Procolophonia , Eosuchia , Millerosauria , Chelonia (turtles), Squamata (lizards and snakes), Rhynchocephalia , Crocodilia , " thecodonts " ( paraphyletic basal Archosauria ), non- avian dinosaurs , pterosaurs , ichthyosaurs , and sauropterygians . In
3648-409: The use of the term "freshwater turtle" to describe Australia's primarily aquatic members of the order Testudines because it avoids misleading use of the word "tortoise" and also is a useful distinction from marine turtles. Most species of tortoises lay small clutch sizes, seldom exceeding 20 eggs, and many species have clutch sizes of only 1–2 eggs. Incubation is characteristically long in most species,
3712-431: The word vent is also a verb meaning "to defecate". Among fish, a true cloaca is present only in elasmobranchs (sharks and rays) and lobe-finned fishes . In lampreys and in some ray-finned fishes , part of the cloaca remains in the adult to receive the urinary and reproductive ducts, although the anus always opens separately. In chimaeras and most teleosts , however, all three openings are entirely separated. With
3776-590: The years following Gauthier's paper. The first such new definition, which attempted to adhere to the standards of the PhyloCode , was published by Modesto and Anderson in 2004. Modesto and Anderson reviewed the many previous definitions and proposed a modified definition, which they intended to retain most traditional content of the group while keeping it stable and monophyletic. They defined Reptilia as all amniotes closer to Lacerta agilis and Crocodylus niloticus than to Homo sapiens . This stem-based definition
3840-670: The zoo was set up. West Bengal officials said records showed Adwaita was at least 150 years old, but other evidence pointed to 250. Adwaita was said to be the pet of Robert Clive . Harriet was a resident at the Australia Zoo in Queensland from 1987 to her death in 2006; she was believed to have been brought to England by Charles Darwin aboard the Beagle and then on to Australia by John Clements Wickham . Harriet died on June 23, 2006, just shy of her 176th birthday. Timothy ,
3904-650: Was Hylonomus , a small and superficially lizard-like animal which lived in Nova Scotia during the Bashkirian age of the Late Carboniferous , around 318 million years ago . Genetic and fossil data argues that the two largest lineages of reptiles, Archosauromorpha (crocodilians, birds, and kin) and Lepidosauromorpha (lizards, and kin), diverged during the Permian period. In addition to
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#17327940052743968-592: Was close to the modern consensus, nonetheless, it became considered inadequate because the actual relationship of turtles to other reptiles was not yet well understood at this time. Major revisions since have included the reassignment of synapsids as non-reptiles, and classification of turtles as diapsids. Gauthier 1994 and Laurin and Reisz 1995's definition of Sauropsida defined the scope of the group as distinct and broader than that of Reptilia, encompassing Mesosauridae as well as Reptilia sensu stricto . A variety of other definitions were proposed by other scientists in
4032-477: Was found by Kehlmaier et al. (2021): Reptiles See text for extinct groups. Reptiles , as commonly defined, are a group of tetrapods with an ectothermic ('cold-blooded') metabolism and amniotic development . Living reptiles comprise four orders : Testudines ( turtles ), Crocodilia ( crocodilians ), Squamata ( lizards and snakes ), and Rhynchocephalia (the tuatara ). As of May 2023, about 12,000 living species of reptiles are listed in
4096-627: Was not the only possible classification scheme: In the Hunterian lectures delivered at the Royal College of Surgeons in 1863, Huxley grouped the vertebrates into mammals , sauroids, and ichthyoids (the latter containing the fishes and amphibians). He subsequently proposed the names of Sauropsida and Ichthyopsida for the latter two groups. In 1866, Haeckel demonstrated that vertebrates could be divided based on their reproductive strategies, and that reptiles, birds, and mammals were united by
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