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94-418: The quagga ( / ˈ k w ɑː x ɑː / or / ˈ k w æ ɡ ə / ) ( Equus quagga quagga ) is an extinct subspecies of the plains zebra that was endemic to South Africa until it was hunted to extinction in the late 19th century. It was long thought to be a distinct species, but early genetic studies have supported it being a subspecies of plains zebra. A more recent study suggested that it

188-529: A phaeton by the sheriff of London in the early 19th century. In an attempt at domesticating the quagga, the British lord George Douglas, 16th Earl of Morton obtained a single male which he bred with a female horse of partial Arabian ancestry. This produced a female hybrid with stripes on its back and legs. Lord Morton's mare was sold and was subsequently bred with a black stallion, resulting in offspring that again had zebra stripes. An account of this

282-624: A change in one corresponding closely to a change in the other. In such cases it may be tentatively concluded that the cline is generated by primary differentiation and therefore moulded by environmental selective pressures. While selection can therefore clearly play a key role in creating clines, it is theoretically feasible that they might be generated by genetic drift alone. It is unlikely that large-scale clines in genotype or phenotype frequency will be produced solely by drift. However, across smaller geographical scales and in smaller populations, drift could produce temporary clines. The fact that drift

376-427: A character gradation from one extreme to the other, isophenes will transect clinal lines at a right angle. Although the term "cline" was first officially coined by Huxley in 1938, gradients and geographic variations in the character states of species have been observed for centuries. Indeed, some gradations have been considered so ubiquitous that they have been labelled ecological "rules" . One commonly cited example of

470-894: A cline. Clines are often cited to be the result of two opposing drivers: selection and gene flow (also known as migration). Selection causes adaptation to the local environment, resulting in different genotypes or phenotypes being favoured in different environments. This diversifying force is countered by gene flow, which has a homogenising effect on populations and prevents speciation through causing genetic admixture and blurring any distinct genetic boundaries. Clines are generally thought to arise under one of two conditions: "primary differentiation" (also known as "primary contact" or "primary intergradation"), or "secondary contact" (also known as "secondary introgression", or "secondary intergradation"). Clines produced through this way are generated by spatial heterogeneity in environmental conditions. The mechanism of selection acting upon organisms

564-442: A comprehensive restoration programme, including such ongoing efforts as eradication of non-native trees. Quaggas, wildebeest , and ostriches , which occurred together during historical times in a mutually beneficial association, could be kept together in areas where the indigenous vegetation has to be maintained by grazing. In early 2006, the third- and fourth-generation animals produced by the project were considered looking much like

658-530: A decreased fitness relative to the parental lines. When this hybrid disadvantage is great enough, natural selection will select for pre-zygotic traits in the homozygous parental lines that reduce the likelihood of disadvantageous hybridisation - in other words, natural selection will favour traits that promote assortative mating in the parental lines. This is known as reinforcement and plays an important role in parapatric and sympatric speciation . Clines can be portrayed graphically on maps using lines that show

752-417: A distinct type of cline where the geographical distribution in question is circular in shape, so that the two ends of the cline overlap with one another, giving two adjacent populations that rarely interbreed due to the cumulative effect of the many changes in phenotype along the cline. The populations elsewhere along the cline interbreed with their geographically adjacent populations as in a standard cline. In

846-733: A gradient in morphology is Gloger's Rule , named after Constantin Gloger , who observed in 1833 that environmental factors and the pigmentation of avian plumage tend to covary with each other, such that birds found in arid areas near the Equator tend to be much darker than those in less arid areas closer to the Poles. Since then, this rule has been extended to include many other animals, including flies, butterflies, and wolves. Other ecogeographical rules include Bergmann's Rule , coined by Carl Bergmann in 1857, which states that homeotherms closer to

940-456: A linear fashion. They may have been sympatric with Burchell's zebra between the Vaal and Orange rivers. This is disputed, and there is no evidence that they interbred. It could also have shared a small portion of its range with Hartmann's mountain zebra ( Equus zebra hartmannae ). Little is known about the behaviour of quaggas in the wild, and it is sometimes unclear what exact species of zebra

1034-465: A long time ago and gene flow has eroded the large character differentiation between the populations. The gradient of a cline is related to another commonly referred to property, clinal width. A cline with a steep slope is said to have a small, or narrow, width, while shallower clines have larger widths. According to Huxley, clines can be classified into two categories; continuous clines and discontinuous stepped clines. These types of clines characterise

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1128-411: A narrow cline of intermediate individuals could be produced, maintained by gene flow counteracting selection. Secondary contact could lead to a cline with a steep gradient if heterozygote disadvantage or frequency-dependent selection exists, as intermediates are heavily selected against. Alternatively, steep clines could exist because the populations have only recently established secondary contact, and

1222-399: A precursor to speciation was therefore ignored, as they were assumed to be evidence of the fact that in contiguous populations gene flow was too strong a force of homogenisation, and selection too weak a force of differentiation, for speciation to take place. However, the existence of particular types of clines, such as ring species , in which populations did not differentiate in allopatry but

1316-423: A selective advantage for quagga mares, as they would therefore have more food reserves when food was scarce. Dimorphism and coat colour could also have evolved through genetic drift due to isolation, but these influences are not mutually exclusive, and could have worked together. Quaggas have been identified in cave art attributed to the indigenous San people of Southern Africa. As it was easy to find and kill,

1410-496: A separate description is warranted. These distinct groups do not interbreed as they are isolated from another, but they can interbreed and have fertile offspring, e.g. in captivity. These subspecies, races, or populations, are usually described and named by zoologists, botanists and microbiologists. In a monotypic species, all populations exhibit the same genetic and phenotypical characteristics. Monotypic species can occur in several ways: Cline (biology) A cline

1504-483: A species is a binomial or binomen, and comprises two Latin words, the first denoting the genus and the second denoting the species. The scientific name of a subspecies is formed slightly differently in the different nomenclature codes. In zoology, under the International Code of Zoological Nomenclature (ICZN), the scientific name of a subspecies is termed a trinomen , and comprises three words, namely

1598-426: A species. Botanists and mycologists have the choice of ranks lower than subspecies, such as variety (varietas) or form (forma), to recognize smaller differences between populations. In biological terms, rather than in relation to nomenclature, a polytypic species has two or more genetically and phenotypically divergent subspecies, races , or more generally speaking, populations that differ from each other so that

1692-496: A stable cline to be maintained when two populations join there must usually be a selective pressure maintaining a degree of differentiation between the two populations. The mechanism of selection maintaining the clines in this scenario is often intrinsic. This means that the fitness of individuals is independent of the external environment, and selection is instead dependent on the genome of the individual. Intrinsic, or endogenous, selection can give rise to clines in characters through

1786-523: A steep cline could indicate large variation in the colour of plumage between adjacent bird populations. It has been previously outlined that such steep clines may be the result of two previously allopatric populations with a large degree of difference in the trait having only recently established gene flow, or where there is strong selection against hybrids. However, it may also reflect a sudden environmental change or boundary. Examples of rapidly changing environmental boundaries like this include abrupt changes in

1880-417: A subspecies. A common criterion for recognizing two distinct populations as subspecies rather than full species is the ability of them to interbreed even if some male offspring may be sterile. In the wild, subspecies do not interbreed due to geographic isolation or sexual selection . The differences between subspecies are usually less distinct than the differences between species. The scientific name of

1974-400: A type of barrier which encourages geographic differentiation. However, some degree of migration is often required to maintain a cline; without it, speciation is likely to eventually occur, as local adaptation can cause reproductive isolation between populations. A classic example of the role of environmental gradients in creating clines is that of the peppered moth, Biston betularia , in

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2068-430: A variety of mechanisms. One way it may act is through heterozygote disadvantage , in which intermediate genotypes have a lower relative fitness than either homozygote genotypes. Because of this disadvantage, one allele will tend to become fixed in a given population, such that populations will consist largely of either AA ( homozygous dominant) or aa (homozygous recessive) individuals. The cline of hetero zygotes that

2162-411: A very steep gradient. Because both primary differentiation and secondary contact can therefore give rise to similar or identical clinal patterns (e.g. gently sloping clines), distinguishing which of these two processes is responsible for generating a cline is difficult and often impossible. However, in some circumstances a cline and a geographic variable (such as humidity) may be very tightly linked, with

2256-438: Is a rank below species , used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology ), but that can successfully interbreed. Not all species have subspecies, but for those that do there must be at least two. Subspecies is abbreviated as subsp. or ssp. and the singular and plural forms are the same ("the subspecies is" or "the subspecies are"). In zoology , under

2350-469: Is a spatial gradient in a single specific trait, rather than in a collection of traits; a single population can therefore have as many clines as it has traits, at least in principle. Additionally, as Julian Huxley recognised, these multiple independent clines may not act in concordance with each other. For example, it has been observed that in Australia, birds generally become smaller the further towards

2444-469: Is a subspecies or a full species, the species name may be written in parentheses. Thus Larus (argentatus) smithsonianus means the American herring gull ; the notation within the parentheses means that some consider it a subspecies of a larger herring gull species and therefore call it Larus argentatus smithsonianus , while others consider it a full species and therefore call it Larus smithsonianus (and

2538-413: Is a weak force upholding the cline however means that clines produced this way are often random (i.e. uncorrelated with environmental variables) and subject to breakdown or reversal over time. Such clines are therefore unstable and sometimes called "transient clines". The steepness, or gradient, of a cline reflects the extent of the differentiation in the character across a geographic range. For example,

2632-436: Is because heterozygosity, mutations and recombination can all produce patterns that deviate from those well-established signals which mark prey as being unpalatable. These individuals are then predated more heavily relative to their counterparts with "normal" markings (i.e. selected against), creating populations dominated by a particular pattern of warning signal. As with heterozygote disadvantage, when these populations join,

2726-479: Is created when these respective populations come into contact is then shaped by the opposing forces of selection and gene flow; even if selection against heterozygotes is great, if there is some degree of gene flow between the two populations, then a steep cline may be able to be maintained. Because instrinsic selection is independent of the external environment, clines generated by selection against hybrids are not fixed to any given geographical area and can move around

2820-639: Is known about the quagga's behaviour, but it may have gathered into herds of 30–50. Quaggas were said to be wild and lively, yet were also considered more docile than the related Burchell's zebra . They were once found in great numbers in the Karoo of Cape Province and the southern part of the Orange Free State in South Africa. After the European settlement of South Africa began, the quagga

2914-462: Is referred to in old reports. The only source that unequivocally describes the quagga in the Free State is that of the British military engineer and hunter William Cornwallis Harris . His 1840 account reads as follows: The geographical range of the quagga does not appear to extend to the northward of the river Vaal. The animal was formerly extremely common within the colony; but, vanishing before

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3008-423: Is therefore external. Species ranges frequently span environmental gradients (e.g. humidity, rainfall, temperature, or day length) and, according to natural selection, different environments will favour different genotypes or phenotypes . In this way, when previously genetically or phenotypically uniform populations spread into novel environments, they will evolve to be uniquely adapted to the local environment, in

3102-559: The International Code of Zoological Nomenclature , the subspecies is the only taxonomic rank below that of species that can receive a name. In botany and mycology , under the International Code of Nomenclature for algae, fungi, and plants , other infraspecific ranks , such as variety , may be named. In bacteriology and virology , under standard bacterial nomenclature and virus nomenclature , there are recommendations but not strict requirements for recognizing other important infraspecific ranks. A taxonomist decides whether to recognize

3196-526: The Pleistocene , and possibly the penultimate glacial maximum. Its distinct coat pattern perhaps evolved rapidly because of geographical isolation and/or adaptation to a drier environment. In addition, plains zebra subspecies tend to have less striping the further south they live, and the quagga was the most southern-living of them all. Other large African ungulates diverged into separate species and subspecies during this period, as well, probably because of

3290-448: The mtDNA of the quagga diverged at a range of roughly 2 percent per million years, similar to other mammal species, and again confirmed the close relation to the plains zebra. Later morphological studies came to different conclusions. A 1999 analysis of cranial measurements found that the quagga was as different from the plains zebra as the latter is from the mountain zebra. A 2004 study of skins and skulls instead suggested that

3384-410: The Equator tend to be smaller than their more northerly or southerly conspecifics. One of the proposed reasons for this cline is that larger animals have a relatively smaller surface area to volume ratio and therefore improved heat conservancy – an important advantage in cold climates. The role of the environment in imposing a selective pressure and producing this cline has been heavily implicated due to

3478-468: The UK. During the 19th century, when the industrial sector gained traction, coal emissions blackened vegetation across northwest England and parts of northern Wales. As a result of this, lighter morphs of the moth were more visible to predators against the blackened tree trunks and were therefore more heavily predated relative to the darker morphs. Consequently, the frequency of the more cryptic melanic morph of

3572-434: The back. It appears to have had a high degree of polymorphism , with some having almost no stripes and others having patterns similar to the extinct southern population of Burchell's zebra, where the stripes covered most of the body except for the hind parts, legs and belly. It also had a broad dark dorsal stripe on its back. It had a standing mane with brown and white stripes. The only quagga to have been photographed alive

3666-412: The base colour is a creamy white and that the stripes are thick and dark. Living in the very southern end of the plains zebra's range, the quagga had a thick winter coat that moulted each year. Its skull was described as having a straight profile and a concave diastema , and as being relatively broad with a narrow occiput . Like other plains zebras, the quagga did not have a dewlap on its neck as

3760-645: The basis of differences in striping patterns, but these differences were since attributed to individual variation within the same populations. Some subspecies and even species, such as E. q. danielli and Hippotigris isabellinus , were based only on illustrations (iconotypes) of aberrant quagga specimens. One craniometric study from 1980 seemed to confirm its affiliation with the horse ( Equus ferus caballus ), but early morphological studies have been noted as being erroneous. Studying skeletons from stuffed specimens can be problematical, as early taxidermists sometimes used donkey and horse skulls inside their mounts when

3854-453: The binomen followed by the name of the subspecies. For example, the binomen for the leopard is Panthera pardus . The trinomen Panthera pardus fusca denotes a subspecies, the Indian leopard . All components of the trinomen are written in italics. In botany , subspecies is one of many ranks below that of species, such as variety , subvariety , form , and subform. To identify the rank,

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3948-797: The case of Larus gulls, the habitats of the end populations even overlap, which introduces questions as to what constitutes a species: nowhere along the cline can a line be drawn between the populations, but they are unable to interbreed. In humans, clines in the frequency of blood types has allowed scientists to infer past population migrations. For example, the Type B blood group reaches its highest frequency in Asia, but become less frequent further west. From this, it has been possible to infer that some Asian populations migrated towards Europe around 2,000 years ago, causing genetic admixture in an isolation by distance model. In contrast to this cline, blood Type A shows

4042-414: The character in the original allopatric populations had a large degree of differentiation. As genetic admixture between the population increases with time however, the steepness of the cline is likely to decrease as the difference in character is eroded. However, if the character in the original allopatric populations was not very differentiated to begin with, the cline between the populations need not display

4136-455: The cold and droughts that affects the Karoo plateau, conditions that were even more severe in prehistoric times, such as during ice ages (other plains zebras live in warmer areas). Isolation, cold, and aridity could thereby have affected quagga evolution, including coat colour and size dimorphism. Since plains zebra mares are pregnant or lactate for much of their lives, larger size could have been

4230-428: The depictions and preserved specimens of the quagga. This type of selective breeding is called breeding back . The practice is controversial, since the resulting zebras will resemble the quaggas only in external appearance, but will be genetically different. The technology to use recovered DNA for cloning has not yet been developed. Subspecies In biological classification , subspecies ( pl. : subspecies)

4324-510: The dreary and desolate plains of some portion of the interior, which has formed their secluded abode, seeking for those more luxuriant pastures where, during the summer months, various herbs thrust forth their leaves and flowers to form a green carpet, spangled with hues the most brilliant and diversified. The practical function of striping in zebras has been debated and it is unclear why the quagga lacked stripes on its hind parts. A cryptic function for protection from predators (stripes obscure

4418-598: The extinction of its kind at the time, and the zoo requested another specimen; hunters believed it could still be found "closer to the interior" in the Cape Colony. Since locals used the term quagga to refer to all zebras, this may have led to the confusion. The extinction of the quagga was internationally accepted by the 1900 Convention for the Preservation of Wild Animals, Birds and Fish in Africa . The last specimen

4512-509: The face of the earth, is surely a disgrace to our latter-day civilization." After the very close relationship between the quagga and extant plains zebras was discovered, Rau started the Quagga Project in 1987 in South Africa to create a quagga-like zebra population by selectively breeding for a reduced stripe pattern from plains zebra stock, with the eventual aim of introducing them to the quagga's former range. To differentiate between

4606-460: The fact that Bergmann's Rule has been observed across many independent lineages of species and continents. For example, the house sparrow , which was introduced in the early 1850s to the eastern United States, evolved a north-south gradient in size soon after its introduction. This gradient reflects the gradient that already existed in the house sparrow's native range in Europe. Ring species are

4700-693: The geographic landscape. Such hybrid zones where hybrids are a disadvantage relative to their parental lines (but which are nonetheless maintained through selection being counteracted by gene flow) are known as "tension zones". Another way in which selection can generate clines is through frequency-dependent selection . Characters that could be maintained by such frequency-dependent selective pressures include warning signals ( aposematism ). For example, aposematic signals in Heliconius butterflies sometimes display steep clines between populations, which are maintained through positive frequency dependence . This

4794-474: The heavy metal content of soils, and the consequent narrow clines produced between populations of Agrostis that are either adapted to these soils with high metal content, or adapted to "normal" soil. Conversely, a shallow cline indicates little geographical variation in the character or trait across a given geographical distance. This may have arisen through weak differential environmental selective pressure, or where two populations established secondary contact

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4888-478: The individual zebra in a herd) and biting flies (which are less attracted to striped objects), as well as various social functions, have been proposed for zebras in general. Differences in hind quarter stripes may have aided species recognition during stampedes of mixed herds, so that members of one subspecies or species would follow its own kind. It has also been evidence that the zebras developed striping patterns as thermoregulation to cool themselves down, and that

4982-409: The joining of two formerly isolated populations which differentiated in allopatry , creating an intermediate zone. This secondary contact scenario may occur, for example, when climatic conditions change, allowing the ranges of populations to expand and meet. Because over time the effect of gene flow will tend to eventually swamp out any regional differences and cause one large homogenous population, for

5076-599: The most docile of the zebras. The Dutch colonists in South Africa had considered this possibility, because their imported work horses did not perform very well in the extreme climate and regularly fell prey to the feared African horse sickness . In 1843, the English naturalist Charles Hamilton Smith wrote that the quagga was 'unquestionably best calculated for domestication, both as regards strength and docility'. Some mentions have been given of tame or domesticated quaggas in South Africa. In Europe, two stallions were used to drive

5170-618: The mountain zebra does. The 2004 morphological study found that the skeletal features of the southern Burchell's zebra population and the quagga overlapped, and that they were impossible to distinguish. Some specimens also appeared to be intermediate between the two in striping, and the extant Burchell's zebra population still exhibits limited striping. It can therefore be concluded that the two subspecies graded morphologically into each other. Today, some stuffed specimens of quaggas and southern Burchell's zebra are so similar that they are impossible to definitely identify as either, since no location data

5264-437: The north of the country they are found. In contrast, the intensity of their plumage colouration follows a different geographical trajectory, being most vibrant where humidity is highest and becoming less vibrant further into the arid centre of the country. Because of this, Huxley described the notion of clines as an "auxiliary taxonomic principle,” meaning that clinal variation in a species is not awarded taxonomic recognition in

5358-450: The originals were unavailable. The quagga is poorly represented in the fossil record, and the identification of these fossils is uncertain, as they were collected at a time when the name "quagga" referred to all zebras. Fossil skulls of Equus mauritanicus from Algeria have been claimed to show affinities with the quagga and the plains zebra, but they may be too badly damaged to allow definite conclusions to be drawn from them. The quagga

5452-407: The peppered moth increased drastically in northern England. This cline in morph colour, from a dominance of lighter morphs in the west of England (which did not suffer as heavily from pollution), to the higher frequency of melanic forms in the north, has slowly been degrading since limitations to sooty emissions were introduced in the 1960s. Clines generated through this mechanism have arisen through

5546-491: The populations of species are allopatric, meaning there is very little or no gene flow amongst populations. The genetic or phenotypic trait in question always shows a steeper gradient between groups than within groups, as in continuous clines. Discontinuous clines follow the same principles as continuous clines by displaying either It was originally assumed that geographic isolation was a necessary precursor to speciation ( allopatric speciation ). The possibility that clines may be

5640-430: The process of speciation . For example, through environmental selection acting on populations and favouring particular allele frequencies, large genetic differences between populations may accumulate (this would be reflected in clinal structure by the presence of numerous very steep clines). If the local genetic differences are great enough, it may lead unfavourable combinations of genotypes and therefore to hybrids being at

5734-416: The process potentially creating a gradient in a genotypic or phenotypic trait. Such clines in characters can not be maintained through selection alone if much gene flow occurred between populations, as this would tend to swamp out the effects of local adaptation. However, because species usually tend to have a limited dispersal range (e.g. in an isolation by distance model), restricted gene flow can serve as

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5828-527: The quagga and the zebras of the project, they refer to it as "Rau quaggas". The founding population consisted of 19 individuals from Namibia and South Africa, chosen because they had reduced striping on the rear body and legs. The first foal of the project was born in 1988. Once a sufficiently quagga-like population has been created, participants in the project plan to release them in the Western Cape. Introduction of these quagga-like zebras could be part of

5922-414: The quagga as a member of that species. They found no evidence for subspecific differentiation based on morphological differences between southern populations of zebras, including the quagga. Modern plains zebra populations may have originated from southern Africa, and the quagga appears to be less divergent from neighbouring populations than the northernmost living population in northeastern Uganda . Instead,

6016-462: The quagga lost them due to living in a cooler climate, although one problem with this is that the mountain zebra lives in similar environments and has a bold striping pattern. A 2014 study strongly supported the biting-fly hypothesis, and the quagga appears to have lived in areas with lesser amounts of fly activity than other zebras. A 2020 study suggested that the sexual dimorphism in size, with quagga mares being larger than stallions, could be due to

6110-467: The quagga was hunted by early Dutch settlers and later by Afrikaners to provide meat or for their skins. The skins were traded or exploited. The quagga was probably vulnerable to extinction due to its restricted range. Local farmers used them as guards for their livestock, as they were likely to attack intruders. Quaggas were said to be lively and highly strung, especially the stallions. Quaggas were brought to European zoos, and an attempt at captive breeding

6204-441: The quagga was not a distinct species, but a subspecies of the plains zebra. In spite of these findings, many authors subsequently kept the plains zebra and the quagga as separate species. A genetic study published in 2005 confirmed the subspecific status of the quagga. It showed that the quagga had little genetic diversity, and that it diverged from the other plains zebra subspecies only between 120,000 and 290,000 years ago, during

6298-486: The quagga was the first extinct animal whose DNA was analysed. The Quagga Project is trying to recreate the phenotype of hair coat pattern by selectively breeding the genetically closest subspecies, which is Burchell's zebra. It has been historically suggested that the name quagga is derived from the Khoikhoi word for zebra ( cf. Tshwa llkoaah 'zebra'), thereby being an onomatopoeic word, resembling

6392-413: The quagga's call, variously transcribed as "kwa-ha-ha", "kwahaah", or "oug-ga". The name is still used colloquially for the plains zebra . The quagga was originally classified as a distinct species , Equus quagga , in 1778 by Dutch naturalist Pieter Boddaert . Traditionally, the quagga and the other plains and mountain zebras were placed in the subgenus Hippotigris . Much debate has occurred over

6486-467: The rank of variety are taken to be names of subspecies (see International Code of Nomenclature of Prokaryotes ). As in botany, subspecies is conventionally abbreviated as "subsp.", and is used in the scientific name: Bacillus subtilis subsp. spizizenii . In zoological nomenclature , when a species is split into subspecies, the originally described population is retained as the "nominotypical subspecies" or "nominate subspecies", which repeats

6580-431: The same climate shift. The simplified cladogram below is based on the 2005 analysis (some taxa shared haplotypes and could, therefore, not be differentiated): Mountain zebra ( E. zebra ) Grévy's zebra ( E. grevyi ) Quagga ( E. q. quagga ) Damara zebra ( E. q. antiquorum )- Chapman's zebra ( E. q. chapmani ) Grant's zebra ( E. q. boehmi ) A 2018 genetic study of plains zebras populations confirmed

6674-418: The same name as the species. For example, Motacilla alba alba (often abbreviated M. a. alba ) is the nominotypical subspecies of the white wagtail ( Motacilla alba ). The subspecies name that repeats the species name is referred to in botanical nomenclature as the subspecies " autonym ", and the subspecific taxon as the "autonymous subspecies". When zoologists disagree over whether a certain population

6768-434: The stallions of extant zebras are the largest. Its coat pattern was unique among equids : zebra-like in the front but more like a horse in the rear. It had brown and white stripes on the head and neck, brown upper parts and a white belly, tail and legs. The stripes were boldest on the head and neck and became gradually fainter further down the body, blending with the reddish brown of the back and flanks, until disappearing along

6862-477: The status of the quagga in relation to the plains zebra. The British zoologist Reginald Innes Pocock in 1902 was perhaps the first to suggest that the quagga was a subspecies of the plains zebra. As the quagga was scientifically described and named before the plains zebra, the trinomial name for the quagga becomes E. quagga quagga under this scheme, and the other subspecies of the plains zebra are placed under E. quagga , as well. Historically, quagga taxonomy

6956-401: The strides of civilisation, is now to be found in very limited numbers and on the borders only. Beyond, on those sultry plains which are completely taken possession of by wild beasts, and may with strict propriety be termed the domains of savage nature, it occurs in interminable herds; and, although never intermixing with its more elegant congeners, it is almost invariably to be found ranging with

7050-529: The study supported a north–south genetic continuum for plains zebras, with the Ugandan population being the most distinct. Zebras from Namibia appear to be the closest genetically to the quagga. The quagga is believed to have been 257 cm (8 ft 5 in) long and 125–135 cm (4 ft 1 in – 4 ft 5 in) tall at the shoulders. Based on measurements of skins, mares were significantly longer and slightly taller than stallions, whereas

7144-563: The subspecific name must be preceded by "subspecies" (which can be abbreviated to "subsp." or "ssp."), as in Schoenoplectus californicus subsp. tatora . In bacteriology , the only rank below species that is regulated explicitly by the code of nomenclature is subspecies , but infrasubspecific taxa are extremely important in bacteriology; Appendix 10 of the code lays out some recommendations that are intended to encourage uniformity in describing such taxa. Names published before 1992 in

7238-484: The terminal ends of the cline nonetheless do not interbreed, cast into doubt whether complete geographical isolation of populations is an absolute requirement for speciation. Because clines can exist in populations connected by some degree of gene flow, the generation of new species from a previously clinal population is termed parapatric speciation . Both extrinsic and intrinsic selection can serve to generate varying degrees of reproductive isolation and thereby instigate

7332-442: The transition in character state from one end of the geographic range to the other. Character states can however additionally be represented using isophenes, defined by Ernst Mayr as "lines of equal expression of a clinally varying character". In other words, areas on maps that demonstrate the same biological phenomenon or character will be connected by something that resembles a contour line. When mapping clines therefore, which follow

7426-425: The user of the notation is not taking a position). A subspecies is a taxonomic rank below species – the only such rank recognized in the zoological code, and one of three main ranks below species in the botanical code. When geographically separate populations of a species exhibit recognizable phenotypic differences, biologists may identify these as separate subspecies; a subspecies is a recognized local variant of

7520-459: The way subspecies or species are. The term cline was coined by Huxley in 1938 from the Greek κλίνειν klinein , meaning "to lean.” While it and the term ecotype are sometimes used interchangeably, they do in fact differ in that ecotype refers to a population which differs from other populations in a number of characters, rather than the single character that varies amongst populations in

7614-526: The way that a genetic or phenotypic trait transforms from one end of its geographical range of the species to the other. In continuous clines, all populations of the species are able to interbreed and there is gene flow throughout the entire range of the species. In this way, these clines are both biologically (no clear subgroups) and geographically (contiguous distribution) continuous. Continuous clines can be further sub-divided into smooth and stepped clines. Unlike in continuous clines, in discontinuous clines

7708-434: The white-tailed gnu and with the ostrich, for the society of which bird especially it evinces the most singular predilection. Moving slowly across the profile of the ocean-like horizon, uttering a shrill, barking neigh, of which its name forms a correct imitation, long files of quaggas continually remind the early traveller of a rival caravan on its march. Bands of many hundreds are thus frequently seen doing their migration from

7802-583: The wild, in the Orange Free State , was extirpated in the late 1870s. The last known wild quagga died in 1878. The specimen in London died in 1872 and the one in Berlin in 1875. The last captive quagga, a female in Amsterdam's Natura Artis Magistra zoo, lived there from 9 May 1867 until it died on 12 August 1883, but its origin and cause of death are unclear. Its death was not recognised as signifying

7896-460: The world, including a juvenile, two foals, and a foetus. In addition, a mounted head and neck, a foot, seven complete skeletons, and samples of various tissues remain. A 24th mounted specimen was destroyed in Königsberg , Germany, during World War II , and various skeletons and bones have also been lost. The quagga had disappeared from much of its range by the 1850s. The last population in

7990-546: Was a mare at the Zoological Society of London 's Zoo . Five photographs of this specimen are known, taken between 1863 and 1870. On the basis of photographs and written descriptions, many observers suggest that the stripes on the quagga were light on a dark background, unlike other zebras. The German naturalist Reinhold Rau , pioneer of the Quagga Project , claimed that this is an optical illusion : that

8084-478: Was extensively hunted, as it competed with domesticated animals for forage. Some were taken to zoos in Europe, but breeding programmes were unsuccessful. The last wild population lived in the Orange Free State; the quagga was extinct in the wild by 1878. The last captive specimen died in Amsterdam on 12 August 1883. Only one quagga was ever photographed alive, and only 23 skins exist today. In 1984,

8178-457: Was featured on a Dutch stamp in 1988. The specimen itself was mounted and is kept in the collection of Naturalis Biodiversity Center in Leiden . It has been on display for special occasions. In 1889, the naturalist Henry Bryden wrote: "That an animal so beautiful, so capable of domestication and use, and to be found not long since in so great abundance, should have been allowed to be swept from

8272-428: Was further complicated because the extinct southernmost population of Burchell's zebra ( Equus quagga burchellii , formerly Equus burchellii burchellii ) was thought to be a distinct subspecies (also sometimes thought a full species, E. burchellii ). The extant northern population, the "Damara zebra", was later named Equus quagga antiquorum , which means that it is today also referred to as E. q. burchellii , after it

8366-488: Was made at London Zoo, but this was halted when a lone stallion killed itself by bashing itself against a wall after losing its temper. On the other hand, captive quaggas in European zoos were said to be tamer and more docile than Burchell's zebra. One specimen was reported to have lived in captivity for 21 years and 4 months, dying in 1872. The quagga was long regarded a suitable candidate for domestication, as it counted as

8460-628: Was published in 1820 by the Royal Society . It is unknown what happened to the hybrid mare itself. This led to new ideas on telegony , referred to as pangenesis by the British naturalist Charles Darwin . At the close of the 19th century, the Scottish zoologist James Cossar Ewart argued against these ideas and proved, with several cross-breeding experiments, that zebra stripes could appear as an atavistic trait at any time. There are 23 known stuffed and mounted quagga specimens throughout

8554-544: Was realised they were the same taxon . The extinct population was long thought very close to the quagga, since it also showed limited striping on its hind parts. As an example of this, Shortridge placed the two in the now disused subgenus Quagga in 1934. Most experts now suggest that the two subspecies represent two ends of a cline . Different subspecies of plains zebras were recognised as members of Equus quagga by early researchers, though much confusion existed over which species were valid. Quagga subspecies were described on

8648-659: Was recorded. The quagga was the southernmost distributed plains zebra, mainly living south of the Orange River . It was a grazer, and its habitat range was restricted to the grasslands and arid interior scrubland of the Karoo region of South Africa , today forming parts of the provinces of Northern Cape , Eastern Cape , Western Cape , and the Free State . These areas were known for distinctive flora and fauna and high amounts of endemism . Quaggas have been reported gathering into herds of 30–50, and sometimes travelled in

8742-437: Was the first extinct animal to have its DNA analysed, and this 1984 study launched the field of ancient DNA analysis. It confirmed that the quagga was more closely related to zebras than to horses, with the quagga and mountain zebra ( Equus zebra ) sharing an ancestor 3–4 million years ago. An immunological study published the following year found the quagga to be closest to the plains zebra. A 1987 study suggested that

8836-519: Was the southernmost cline or ecotype of the species. The quagga is believed to have been around 257 cm (8 ft 5 in) long and 125–135 cm (4 ft 1 in – 4 ft 5 in) tall at the shoulders. It was distinguished from other zebras by its limited pattern of primarily brown and white stripes, mainly on the front part of the body. The rear was brown and without stripes, and appeared more horse-like. The distribution of stripes varied considerably between individuals. Little

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