Khoisan

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Khoisan

 

Khoisan

San man of Namibia (2006 photograph)
Total population
~ 400,000 (c. 2010)
Regions with significant populations
Southern Africa
Languages
Afrikaans, Khoisan languages
Religion
Mainly Christian and African Traditional Religion (San religion)
Related ethnic groups
perhaps Sandawe people

Khoisan (/ˈkɔɪsɑːn/), or according to the contemporary Khoekhoegowab orthography Khoe-Sān (pronounced: [kxʰoesaːn]), is a catch-all term for the "non-Bantu" indigenous peoples of Southern Africa, combining the Khoekhoen (formerly "Khoikhoi") and the Sān or Sākhoen (also, in Afrikaans: Boesmans, or in English: Bushmen, after Dutch Boschjesmens; and Saake in the Nǁng language).

Khoekhoen, specifically, were formerly known as “Hottentots”, which was an onomatopoeic term (from Dutch hot-en-tot) referring to the click consonants prevalent in the Khoekhoe languages, as they are in all the languages grouped under "Khoesān". Dutchmen in the early Cape settlement would ply Khoekhoen with liquor as an inducement for them to perform a ritual dance. The lyric accompanying the dance sounded, in Dutch ears, like “hot-en-tot”.

Sān are popularly thought of as foragers in the Kalahari Desert and regions of Botswana, Namibia, Angola, Zambia, Zimbabwe, Lesotho and South Africa. The word sān is from the Khoekhoe language and simply refers to foragers ("those who pick things up from the ground") who do not own livestock. As such it was used in reference to all hunter-gatherer populations of the Southern African region who Khoekhoe-speaking communities came into contact with, and was largely a term referring to a lifestyle, distinct from a pastoralist or agriculturalist one, not any particular ethnicity. While there are attendant cosmologies and languages associated with such a radical lifestyle, the term is an economic designator, rather than a cultural or ethnic one. However, Khoekhoen is considered to have ethnic meaning, as it refers to a number of historical populations of speakers of closely related languages that are considered to be the historical pastoralist communities in the South African Cape region, through to Namibia, where Khoekhoe populations of Nama and Damara people are prevalent ethnicities.

These Khoekhoe nations and Sān are grouped under the single term Khoesān as representing the indigenous substrate population of Southern Africa prior to the hypothesised Bantu expansion reaching the area, roughly between 1,500–2,000 years ago.

Many Khoesān peoples are the direct descendants of a very early dispersal of anatomically modern humans to Southern Africa, before 150,000 years ago. Their languages show a vague typological similarity, largely confined to the prevalence of click consonants, and they are not verifiably derived from a common proto-language, but are today split into at least three separate and unrelated language families (Khoe-Kwadi, !Ui-Taa and Kx'a). It has been suggested that the Khoekhoeǁaen (Khoekhoe peoples) may represent Late Stone Age arrivals to Southern Africa, possibly displaced by Bantu immigration.

The compound term Khoisan / Khoesān is a modern anthropological convention, in use since the early-to-mid 20th century. Khoisan is a coinage by Leonhard Schulze in the 1920s and popularised by Isaac Schapera. It enters wider usage from the 1960s, based on the proposal of a "Khoisan" language family by Joseph Greenberg.

Khoesān peoples were historically also grouped as Cape Blacks (Afrikaans: Kaap Swartes) or Western Cape Blacks (Afrikaans: Wes-Kaap Swartes) to distinguish them from the Niger-Congo-speaking "Bantoid" or "Congoid" blacks of the other parts of sub-Saharan Africa. Derived from this is the term Capoid used in 20th century anthropological literature. An equivalent term derived from the compound Khoisan is Khoisanid, in use primarily in genetic genealogy.

The term Khoisan (also spelled KhoiSan, Khoi-San, Khoe-San) has also been introduced in South African usage as a self-designation after the end of apartheid, in the late 1990s. Since the 2010s, there has been a "Khoisan activist" movement demanding recognition and land rights from the Bantu majority.

San man collecting devil's claw (2017)

 

History

Origins

Approximate area of the origin of L0d and L0k haplogroups in southern Africa, dated to before 90,000 years ago by Behar et al. (2008).

 

It is suggested that the ancestors of the modern Khoisan expanded to Southern Africa before 150,000 years ago, possibly as early as before 260,000 years ago, so that by the beginning of the MIS 5 "megadrought", 130,000 years ago, there were two ancestral population clusters in Africa, bearers of mt-DNA haplogroup L0 in southern Africa, ancestral to the Khoi-San, and bearers of haplogroup L1-6 in central/eastern Africa, ancestral to everyone else.

Due to their early expansion and separation, the populations ancestral to the Khoisan have been estimated as having represented the "largest human population" during the majority of the anatomically modern human timeline, from their early separation before 150 ka until the recent peopling of Eurasia some 70 kya. They were much more widespread than today, their modern distribution being due to their decimation in the course of the Bantu expansion. They were dispersed throughout much of Southern and South-Eastern Africa. There was also a significant back-migration of bearers of L0 towards eastern Africa between 120 and 75 kya. Rito et al. (2013) speculate that pressure from such back-migration may even have contributed to the dispersal of East African populations out of Africa at about 70 kya. "By ~130 ka two distinct groups of anatomically modern humans co-existed in Africa: broadly, the ancestors of many modern-day Khoe and San populations in the south and a second central/eastern African group that includes the ancestors of most extant worldwide populations. Early modern human dispersals correlate with climate changes, particularly the tropical African “megadroughts” of MIS 5 (marine isotope stage 5, 135–75 ka) which paradoxically may have facilitated expansions in central and eastern Africa, ultimately triggering the dispersal out of Africa of people carrying haplogroup L3 ~60 ka. Two south to east migrations are discernible within haplogroup L0. One, between 120 and 75 ka, represents the first unambiguous long-range modern human dispersal detected by mtDNA and might have allowed the dispersal of several markers of modernity. A second one, within the last 20 ka signalled by L0d, may have been responsible for the spread of southern click-consonant languages to eastern Africa, contrary to the view that these eastern examples constitute relics of an ancient, much wider distribution." 

      Approximate distribution of Middle Stone Age Capoids at the end of the Pleistocene (12,000 years ago) shown in magenta (according to C. S. Coon 1963).

 

The term Capoid was introduced as a racial category uniting the Khoikhoi and San peoples as separate from other sub-Saharan populations was proposed by Carleton S. Coon (1962). It is named for the Cape of Good Hope. Coon (1962) proposed that the term "Negroid" should be abandoned, and the sub-Saharan African populations of West African stock (including the Bantu) should be termed "Congoid" instead. Cavalli-Sforza at al. (1994) used the term Khoisanid instead of Coon's "Capoid". The observation of a significant difference between the Khoisan and the populations of West African stock was not original to Coon, it had been noted as early as 1684 François Bernier, the early modern author who originally introduced the French word race to refer to the large divisions of mankind. Bernier outside of five large divisions described in more detail proposes the possible addition of more categories, primarily for "the Blacks of the Cape of Good Hope" (les Noirs du Cap de bonne Esperance), which seemed to him to be of significantly different build from most other populations below the Sahara.

Late Stone Age

Schematic representation of the "out of South Africa" migration of the post-Eemian Middle to Late Stone Age (after 100 kya) inferred from mtDNA haplogroup L0 in modern African populations (Rito et al. 2013).

 

The Khoisanid populations ancestral to the Khoisan were spread throughout much of Southern and Eastern Africa throughout the Late Stone Age, after about 75 ka. A further expansion, dated to about 20 ka, has been proposed based on the distribution of the L0d haplogroup. Rosti et al. suggest a connection of this recent expansion with the spread of click consonants to eastern African languages (Hadza language).

The Late Stone Age Sangoan industry occupied southern Africa in areas where annual rainfall is less than a metre (1000 mm; 39.4 in). The contemporary San and Khoi peoples resemble those represented by the ancient Sangoan skeletal remains.

Against the traditional interpretation that finds a common origin for the Khoi and San, other evidence has suggested that the ancestors of the Khoi peoples are relatively recent pre-Bantu agricultural immigrants to Southern Africa, who abandoned agriculture as the climate dried and either joined the San as hunter-gatherers or retained pastoralism.

Bantu expansion

Since the arrival of the Bantu expansion in Southern Africa over 1,500 years ago, linguistic influence is seen in the adoption of click consonants and loan words from Khoisan into the Xhosa and Zulu languages. Bantu-speaking communities would have reached southern Africa from the Congo basin by about the 6th century AD. The advancing Bantu encroached on the Khoikhoi territory, forcing survivors of the indigenous populations to move to more arid areas of the Kalahari.

Their husbandry of sheep, goats and cattle grazing in fertile valleys across the region provided a stable, balanced diet, and allowed the Khoikhoi to live in larger groups in a region previously occupied by the San, who were subsistence hunter-gatherers. Advancing Bantu in the 3rd-6th century AD encroached on the Khoikhoi territory, pushing them into more arid areas. The Bantu people, with advanced agriculture and metalworking technology, outcompeted and intermarried with the Khoisan, becoming the dominant population of South-Eastern Africa before the arrival of the Dutch colonists in 1652.

After the arrival of the Bantu, the Khoisan and their pastoral or hunter-gatherer ways of life remained predominant west of the Fish River in South Africa and in deserts throughout their region, where the drier climate precluded the growth of Bantu crops suited for warmer and wetter climates.

Historical period

The Khoikhoi enter the historical record with their first contact with Portuguese explorers, about 1,000 years after their displacement by the Bantu. Local population dropped after the Khoi were exposed to smallpox from Europeans. The Khoi waged more frequent attacks against Europeans when the Dutch East India Company enclosed traditional grazing land for farms. Khoikhoi social organisation was profoundly damaged and, in the end, destroyed by colonial expansion and land seizure from the late 17th century onwards. As social structures broke down, some Khoikhoi people settled on farms and became bondsmen (bondservants) or farm workers; others were incorporated into existing clan and family groups of the Xhosa people. Georg Schmidt, a Moravian Brother from Herrnhut, Saxony, now Germany, founded Genadendal in 1738, which was the first mission station in southern Africa, among the Khoi people in Baviaanskloof in the Riviersonderend Mountains. Early European settlers sometimes intermarried with Khoikhoi women, resulting in a sizeable mixed-race population now known as the Griqua.

Andries Stockenström facilitated the creation of the "Kat River" Khoi settlement near the eastern frontier of the Cape Colony. The settlements thrived and expanded, and Kat River quickly became a large and successful region of the Cape that subsisted more or less autonomously. The people were predominantly Afrikaans-speaking Gonaqua Khoi, but the settlement also began to attract other Khoi, Xhosa and mixed-race groups of the Cape.

The so-called "Bushman wars" were to a large extent the response of the San after their dispossession.

At the start of the 18th century, the Khoikhoi in the Western Cape lived in a co-operative state with the Dutch. By the end of the century the majority of the Khoisan operated as 'wage labourers', not that dissimilar to slaves. Geographically, the further away the labourer was from Cape Town, the more difficult it became to transport agricultural produce to the markets. The issuing of grazing licences north of the Berg River in what was then the Tulbagh Basin propelled colonial expansion in the area. This system of land relocation led to the Khoijhou losing their land and livestock as well as dramatic change in the social, economic and political development.

After the defeat of the Xhosa rebellion in 1853, the new Cape Government endeavoured to grant the Khoi political rights to avert future racial discontent. The government enacted the Cape franchise in 1853, which decreed that all male citizens meeting a low property test, regardless of colour, had the right to vote and to seek election in Parliament. This non-racial principle was later abolished by the apartheid Government.

In the Herero and Namaqua genocide in German South-West Africa, over 10,000 Nama are estimated to have been killed during 1904–1907.

The San of the Kalahari were described in Specimens of Bushman Folklore by Wilhelm H. I. Bleek and Lucy C. Lloyd (1911). They were brought to the globalised world's attention in the 1950s by South African author Laurens van der Post in a six-part television documentary. The Ancestral land conflict in Botswana concerns the Central Kalahari Game Reserve (CKGR), established in 1961 for wildlife, while the San were permitted to continue their hunter-gatherer lifestyle. In the 1990s, the government of Botswana began a policy of "relocating" CKGR residents outside the reserve. In 2002, the government cut off all services to CKGR residents. A legal battle began, and in 2006 the High Court of Botswana ruled that the residents had been forcibly and unconstitutionally removed. The policy of relocation continued, however, and in 2012 the San people (Basarwa) appealed to the United Nations to force the government to recognise their land and resource rights.

Following the end of Apartheid in 1994, the term "Khoisan" has gradually come to be used as a self-designation by South African Khoikhoi as representing the "first nations" of South Africa vis-a-vis the ruling Bantu majority. A conference on "Khoisan Identities and Cultural Heritage" was organised by the University of the Western Cape in 1997. and "Khoisan activism" has been reported in the South African media beginning in 2015.

The South African government allowed Khoisan families (up until 1998) to pursue land claims which existed prior to 1913. The South African Deputy Chief Land Claims Commissioner, Thami Mdontswa, has said that constitutional reform would be required to enable Khoisan people to pursue further claims to land from which their direct ancestors were removed prior to 9 June 1913.

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  "Bosjemans frying locusts", aquatint by Samuel Daniell (1805).
  
  
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  San woman in Namibia (1984 photograph)
  

Languages

Green: The modern distribution of the Khoisan languages spoken by Khoi and San peoples, plus the Sandawe language and Hadza language of Tanzania.

The "Khoisan languages" were proposed as a linguistic phylum by Joseph Greenberg in 1955. Their genetic relationship was questioned later in the 20th century, and the term now serves mostly as a convenience term without implying genetic unity, much like "Papuan" and "Australian" are. Their most notable uniting feature is their click consonants. 

They are categorized in two families, and a number of possible language isolates.

The Kx'a family was proposed in 2010, combining the ǂ’Amkoe (ǂHoan) language with the ǃKung (Juu) dialect cluster. !Kung includes about a dozen dialects, with no clear-cut delineation between them. Sands et al. (2010) propose a division into four clusters:

• Northern !Kung (Sekele), spoken in Angola around the Cunene, Cubango, Cuito, and Cuando rivers (but with many refugees now in Namibia),
• North-Central !Kung (Ekoka), spoken in Namibia between the Ovambo River and the Angolan border,
• Central !Kung, spoken around Grootfontein, Namibia, west of the central Omatako River and south of the Ovambo River
• Southeastern !Kung (Juǀ'hoan), spoken in Botswana east of the Okavango Delta, and northeast Namibia from near Windhoek to Rundu, Gobabis, and the Caprivi Strip.

The Khoi (Khoe) family is divided into a Khoikhoi (Khoekhoe and Khoemana dialects) and a Kalahari (Tshu–Khwe) branch. The Kalahari branch of Khoe includes Shua and Tsoa (with dialects), and Kxoe, Naro, Gǁana and ǂHaba (with dialects). Khoe also has been tentatively aligned with Kwadi ("Kwadi–Khoe"), and more speculatively with the Sandawe language of Tanzania ("Khoe–Sandawe"). The Hadza language of Tanzania has been associated with the Khoisan group due to the presence of click consonants. 

Physical characteristics and genetics

Drawing of a Khoikhoi woman and man, the woman shown as exhibiting steatopygia (1900 drawing).

 

Charles Darwin wrote about the Khoisan and sexual selection in The Descent of Man in 1882, commenting that their steatopygia evolved through sexual selection in human evolution, and that "the posterior part of the body projects in a most wonderful manner".

In the 1990s, genomic studies of the world's peoples found that the Y chromosome of San men share certain patterns of polymorphisms that are distinct from those of all other populations. Because the Y chromosome is highly conserved between generations, this type of DNA test is used to determine when different subgroups separated from one another, and hence their last common ancestry. The authors of these studies suggested that the San may have been one of the first populations to differentiate from the most recent common paternal ancestor of all extant humans. Various Y-chromosome studies since confirmed that the Khoisan carry some of the most divergent (oldest) Y-chromosome haplogroups. These haplogroups are specific sub-groups of haplogroups A and B, the two earliest branches on the human Y-chromosome tree.

Similar to findings from Y-Chromosome studies, mitochondrial DNA studies also showed evidence that the Khoisan people carry high frequencies of the earliest haplogroup branches in the human mitochondrial DNA tree. The most divergent (oldest) mitochondrial haplogroup, L0d, has been identified at its highest frequencies in the southern African Khoi and San groups. The distinctiveness of the Khoisan in both matrilineal and patrilineal groupings is a further indicator that they represent a population historically distinct from other Africans.

Quagga

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Quagga

 

Quagga
Quagga mare at London Zoo, 1870, the only specimen photographed alive
Conservation status
Extinct  (1883) (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Perissodactyla
Family:	Equidae
Genus:	Equus
Species:	E. quagga
Subspecies:	†E. q. quagga
Trinomial name
Equus quagga quagga (Boddaert, 1785)
Former range in red

The quagga (/ˈkwɑːxɑː/ or /ˈkwæɡə/) (Equus quagga quagga) was a subspecies of plains zebra that lived in South Africa until becoming extinct late in the 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 was merely the southernmost cline or ecotype of the species. The name was derived from its call, which sounded like "kwa-ha-ha".

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 shoulder. 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 therefore more horse-like. The distribution of stripes varied considerably between individuals. Little 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 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 Dutch settlement of South Africa began, the quagga was heavily 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, and 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 are preserved today. In 1984, the quagga was the first extinct animal to have its DNA analysed, and the Quagga Project is trying to recreate the phenotype of hair coat pattern and related characteristics by selectively breeding Burchell's zebras.

Taxonomy

1804 illustration by Samuel Daniell, which was the basis of the supposed subspecies E. q. danielli

 

The name "quagga" is derived from the Khoikhoi word for zebra and is onomatopoeic, being said to resemble 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 the status of the quagga in relation to the plains zebra. It 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. Quaggas have also been identified in cave art attributed to the San. Reginald Innes Pocock was perhaps the first to suggest that the quagga was a subspecies of plains zebra in 1902. 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 plains zebra are placed under E. quagga, as well.

Historically, quagga taxonomy 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 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 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 only based on illustrations (iconotypes) of aberrant quagga specimens. Some authors have described the quagga as a kind of wild horse rather than a zebra, and one craniometric study from 1980 seemed to confirm its affiliation with the horse (Equus caballus). Early morphological studies have been pointed out to be erroneous; using skeletons from stuffed specimens can be problematical, as early taxidermists sometimes used donkey and horse skulls inside their mounts when the originals were unavailable.

Evolution

The mare in London Zoo, 1870

The quagga 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 the mtDNA of the quagga diverged at a range of roughly 2% per million years, similar to other mammal species, and again confirmed the close relation to the plains zebra.

Later morphological studies came to conflicting 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 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.

Skin in Berlin's Natural History Museum, which has been sampled for DNA

 

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 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 the same climate shift.

A 2018 genetic study of plains zebras populations confirmed the quagga as a member of the 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, 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.

Description

Painting of a stallion in Louis XVI's menagerie at Versailles by Nicolas Maréchal, 1793

 

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 shoulder. 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 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 London mare with keeper, 1864

 

The only quagga to have been photographed alive 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. Reinhold Rau, pioneer of the Quagga Project, claimed that this is an optical illusion: that the base colour is a creamy white and that the stripes are thick and dark. Embryological evidence supports zebras being dark coloured with white as an addition.

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 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 was recorded. The female specimens used in the study were larger than the males on average.

Behaviour and ecology

Specimen with passenger pigeon, Naturhistorisches Museum, Basel

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.

Little is known about the behaviour of quaggas in the wild, and it is sometimes unclear what exact species of zebra is referred to in old reports. The only source that unequivocally describes the quagga in the Free State is that of the English military engineer and hunter Major Sir 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 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 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 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.

1777 illustration of a live quagga colt and a bagged adult Burchell's zebra male, by Robert Jacob Gordon

 

Quaggas have been reported gathering into herds of 30–50, and sometimes travelled in 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).

Quaggas were said to be lively and highly strung, especially the stallions. During the 1830s, quaggas were used as harness animals for carriages in London, the males probably being gelded to mitigate their volatile nature. Local farmers used them as guards for their livestock, as they were likely to attack intruders. 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.

Live stallion at the Royal College of Surgeons, painted by Jacques-Laurent Agasse in the early 1800s

 

Since the practical function of striping has not been determined for zebras in general, it is unclear why the quagga lacked stripes on its hind parts. A cryptic function for protection from predators (stripes obscure 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 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.

Decline and extinction

One of seven known skeletons, Grant Museum

As it was easy to find and kill, the quagga was hunted by early Dutch settlers and later by Afrikaners to provide meat or for their skins. The skins were traded or used locally. The quagga was probably vulnerable to extinction due to its limited distribution, and it may have competed with domestic livestock for forage. The quagga had disappeared from much of its range by the 1850s. The last population in the wild, in the Orange Free State, was extirpated in the late 1870s. The last known wild quagga died in 1878.

Quaggas were captured and shipped to Europe, where they were displayed in zoos. Lord Morton tried to save the animal from extinction by starting a captive-breeding programme. He was only able to obtain a single male, which in desperation he bred with a female horse. This produced a female hybrid with zebra 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 was published in 1820 by the Royal Society. This led to new ideas on telegony, referred to as pangenesis by 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 can pop up as an atavistic trait at any time.

The quagga was long regarded a suitable candidate for domestication, as it counted as the most docile of the striped horses. The earliest Dutch colonists in South Africa had already fantasized about 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'. Only a few descriptions have been given of tame or domesticated quaggas in South Africa. In Europe, the only confirmed cases are two stallions driven in a phaeton by Joseph Wilfred Parkins, sheriff of London in 1819-1820, and the quaggas and their hybrid offspring of London Zoo, which were used to pull a cart and transport vegetables from the market to the zoo. Nevertheless, the reveries continued long after the death of the last quagga in 1883. 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 the face of the earth, is surely a disgrace to our latter-day civilization."

The last known quagga and a great auk, in Naturalis, Leiden

 

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 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 was featured on a Dutch stamp in 1988. There are 23 known stuffed and mounted quagga specimens throughout 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.

Breeding back project

Regular plains zebras and Quagga Project zebras in Mokala National Park

 

After the very close relationship between the quagga and extant plains zebras was discovered, Reinhold 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 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 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 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.

Evolutionary taxonomy

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Evolutionary_taxonomy 

 

Evolutionary taxonomy, evolutionary systematics or Darwinian classification is a branch of biological classification that seeks to classify organisms using a combination of phylogenetic relationship (shared descent), progenitor-descendant relationship (serial descent), and degree of evolutionary change. This type of taxonomy may consider whole taxa rather than single species, so that groups of species can be inferred as giving rise to new groups. The concept found its most well-known form in the modern evolutionary synthesis of the early 1940s.

Evolutionary taxonomy differs from strict pre-Darwinian Linnaean taxonomy (producing orderly lists only), in that it builds evolutionary trees. While in phylogenetic nomenclature each taxon must consist of a single ancestral node and all its descendants, evolutionary taxonomy allows for groups to be excluded from their parent taxa (e.g. dinosaurs are not considered to include birds, but to have given rise to them), thus permitting paraphyletic taxa.

Origin of evolutionary taxonomy

​Jean-Baptiste Lamarck's 1815 diagram showing branching in the course of invertebrate evolution

 

Evolutionary taxonomy arose as a result of the influence of the theory of evolution on Linnaean taxonomy. The idea of translating Linnaean taxonomy into a sort of dendrogram of the Animal and Plant Kingdoms was formulated toward the end of the 18th century, well before Charles Darwin's book On the Origin of Species was published. The first to suggest that organisms had common descent was Pierre-Louis Moreau de Maupertuis in his 1751 Essai de Cosmologie, Transmutation of species entered wider scientific circles with Erasmus Darwin's 1796 Zoönomia and Jean-Baptiste Lamarck's 1809 Philosophie Zoologique. The idea was popularised in the English-speaking world by the speculative but widely read Vestiges of the Natural History of Creation, published anonymously by Robert Chambers in 1844.

Following the appearance of On the Origin of Species, Tree of Life representations became popular in scientific works. In On the Origin of Species, the ancestor remained largely a hypothetical species; Darwin was primarily occupied with showing the principle, carefully refraining from speculating on relationships between living or fossil organisms and using theoretical examples only. In contrast, Chambers had proposed specific hypotheses, the evolution of placental mammals from marsupials, for example.

Following Darwin's publication, Thomas Henry Huxley used the fossils of Archaeopteryx and Hesperornis to argue that the birds are descendants of the dinosaurs. Thus, a group of extant animals could be tied to a fossil group. The resulting description, that of dinosaurs "giving rise to" or being "the ancestors of" birds, exhibits the essential hallmark of evolutionary taxonomic thinking. 

The past three decades have seen a dramatic increase in the use of DNA sequences for reconstructing phylogeny and a parallel shift in emphasis from evolutionary taxonomy towards Hennig's 'phylogenetic systematics'.

Today, with the advent of modern genomics, scientists in every branch of biology make use of molecular phylogeny to guide their research. One common method is multiple sequence alignment.

Cavalier-Smith, G. G. Simpson and Ernst Mayr are some representative evolutionary taxonomists.

New methods in modern evolutionary systematics

Efforts in combining modern methods of cladistics, phylogenetics, and DNA analysis with classical views of taxonomy have recently appeared. Certain authors have found that phylogenetic analysis is acceptable scientifically as long as paraphyly at least for certain groups is allowable. Such a stance is promoted in papers by Tod F. Stuessy and others. A particularly strict form of evolutionary systematics has been presented by Richard H. Zander in a number of papers, but summarized in his "Framework for Post-Phylogenetic Systematics".

Briefly, Zander's pluralistic systematics is based on the incompleteness of each of the theories: A method that cannot falsify a hypothesis is as unscientific as a hypothesis that cannot be falsified. Cladistics generates only trees of shared ancestry, not serial ancestry. Taxa evolving seriatim cannot be dealt with by analyzing shared ancestry with cladistic methods. Hypotheses such as adaptive radiation from a single ancestral taxon cannot be falsified with cladistics. Cladistics offers a way to cluster by trait transformations but no evolutionary tree can be entirely dichotomous. Phylogenetics posits shared ancestral taxa as causal agents for dichotomies yet there is no evidence for the existence of such taxa. Molecular systematics uses DNA sequence data for tracking evolutionary changes, thus paraphyly and sometimes phylogenetic polyphyly signal ancestor-descendant transformations at the taxon level, but otherwise molecular phylogenetics makes no provision for extinct paraphyly. Additional transformational analysis is needed to infer serial descent. 

Cladogram of the moss genus Didymodon showing taxon transformations. Colors denote dissilient groups.

 

The Besseyan cactus or commagram is the best evolutionary tree for showing both shared and serial ancestry. First, a cladogram or natural key is generated. Generalized ancestral taxa are identified and specialized descendant taxa are noted as coming off the lineage with a line of one color representing the progenitor through time. A Besseyan cactus or commagram is then devised that represents both shared and serial ancestry. Progenitor taxa may have one or more descendant taxa. Support measures in terms of Bayes factors may be given, following Zander's method of transformational analysis using decibans.

Cladistic analysis groups taxa by shared traits but incorporates a dichotomous branching model borrowed from phenetics. It is essentially a simplified dichotomous natural key, although reversals are tolerated. The problem, of course, is that evolution is not necessarily dichotomous. An ancestral taxon generating two or more descendants requires a longer, less parsimonious tree. A cladogram node summarizes all traits distal to it, not of any one taxon, and continuity in a cladogram is from node to node, not taxon to taxon. This is not a model of evolution, but is a variant of hierarchical cluster analysis (trait changes and non-ultrametric branches. This is why a tree based solely on shared traits is not called an evolutionary tree but merely a cladistic tree. This tree reflects to a large extent evolutionary relationships through trait transformations but ignores relationships made by species-level transformation of extant taxa.

A Besseyan cactus evolutionary tree of the moss genus Didymodon with generalized taxa in color and specialized descendants in white. Support measures are given in terms of Bayes factors, using deciban analysis of taxon transformation. Only two progenitors are considered unknown shared ancestors.

Phylogenetics attempts to inject a serial element by postulating ad hoc, undemonstrable shared ancestors at each node of a cladistic tree. There are in number, for a fully dichotomous cladogram, one less invisible shared ancestor than the number of terminal taxa. We get, then, in effect a dichotomous natural key with an invisible shared ancestor generating each couplet. This cannot imply a process-based explanation without justification of the dichotomy, and supposition of the shared ancestors as causes. The cladistic form of analysis of evolutionary relationships cannot falsify any genuine evolutionary scenario incorporating serial transformation, according to Zander.

Zander has detailed methods for generating support measures for molecular serial descent and for morphological serial descent using Bayes factors and sequential Bayes analysis through Turing deciban or Shannon informational bit addition.

The Tree of Life

Evolution of the vertebrates at class level, width of spindles indicating number of families. Spindle diagrams are often used in evolutionary taxonomy.

As more and more fossil groups were found and recognized in the late 19th and early 20th century, palaeontologists worked to understand the history of animals through the ages by linking together known groups. The Tree of life was slowly being mapped out, with fossil groups taking up their position in the tree as understanding increased. 

These groups still retained their formal Linnaean taxonomic ranks. Some of them are paraphyletic in that, although every organism in the group is linked to a common ancestor by an unbroken chain of intermediate ancestors within the group, some other descendants of that ancestor lie outside the group. The evolution and distribution of the various taxa through time is commonly shown as a spindle diagram (often called a Romerogram after the American palaeontologist Alfred Romer) where various spindles branch off from each other, with each spindle representing a taxon. The width of the spindles are meant to imply the abundance (often number of families) plotted against time.

Vertebrate palaeontology had mapped out the evolutionary sequence of vertebrates as currently understood fairly well by the closing of the 19th century, followed by a reasonable understanding of the evolutionary sequence of the plant kingdom by the early 20th century. The tying together of the various trees into a grand Tree of Life only really became possible with advancements in microbiology and biochemistry in the period between the World Wars.

Terminological difference

The two approaches, evolutionary taxonomy and the phylogenetic systematics derived from Willi Hennig, differ in the use of the word "monophyletic". For evolutionary systematicists, "monophyletic" means only that a group is derived from a single common ancestor. In phylogenetic nomenclature, there is an added caveat that the ancestral species and all descendants should be included in the group. The term "holophyletic" has been proposed for the latter meaning. As an example, amphibians are monophyletic under evolutionary taxonomy, since they have arisen from fishes only once. Under phylogenetic taxonomy, amphibians do not constitute a monophyletic group in that the amniotes (reptiles, birds and mammals) have evolved from an amphibian ancestor and yet are not considered amphibians. Such paraphyletic groups are rejected in phylogenetic nomenclature, but are considered a signal of serial descent by evolutionary taxonomists.