how was the quagga related to other zebras?
There has never been unanimous agreement between zoologists regarding the Quagga’s relationship to other members of the horse family. Some regarded the Quagga as a full zebra species, while others treated it as the southern-most subspecies of the widely distributed Plains Zebra (often referred to as Burchell’s Zebra). While most scientists accept the Quagga as belonging to the zebras, in 1980 one researcher did suggest that the Quagga was more closely related to the horse than to the zebra.
It was thought that this question about the Quagga’s relationship to other Equids, would probably never be answered, as the Quagga had long since become extinct, thus precluding the study of the living animal.
Against all expectations, the question of the taxonomic status of the Quagga was answered in 1984. Three groups of scientists from the University of California undertook molecular studies on dried flesh and blood samples that had been removed from Quagga skins during re-mounting by Reinhold Rau (Taxidermist, South African Museum) of four old museum specimens in 1969/70 and 1980/81. The biochemists obtained protein and DNA fragments from the samples. The DNA fragments were successfully cloned. Both the protein and the DNA confirmed the status of the Quagga as a subspecies of the Plains Zebra.
There is a lot of confusion about Burchell’s Zebra, Quagga and other zebras, despite there being only three zebra species.
The reason for this is in the history of zebra descriptions and naming. Whenever an early explorer took a zebra skin from Africa to Europe, it did not match any of those in collections, so, it "needed a name".
That there is enormous individual variation in, especially, the Plains Zebra (which is often refered to as Burchell’s Zebra), had not been expected nor realized until the early 1900’s. By then, the Quagga, which had been described and named in 1788, had become extinct. The Burchell’s Zebra, described and named in 1824, was still around.
Gradually, further north, somewhat more extensively-striped zebra populations became known. It was noticed that they were very similar to Burchell’s Zebra, and they were described and named as subspecies of Burchell’s Zebra. These subspecies were usually given names of explorers, like Chapman, Wahlberg, Selous, Grant, Boehm, etc. Eventually the zebra population from which William Burchell had taken a skin to the British Museum, had been wiped out, but "Burchell’s Zebra subspecies" continue to exist in many areas of Africa.
Now I must explain why I prefer to speak of Plains Zebra, rather than Burchell’s Zebra, as is often done. The original Burchell’s Zebra (sometimes refered to as the "true" Burchell’s Zebra) is, or rather was, one of the subspecies of the species under discussion. Consequently, all the other subspecies (with explorers’ names) should be called Chapman’s Burchell’s Zebra, Wahlberg’s Burchell’s Zebra, Selous’s Burchell’s Zebra, and the "extinct" subspecies burchelli should be called Burchell’s Burchell’s Zebra. This would be ridiculous. Because the species that we are discussing here, lives on the plains, in contrast to the Mountain Zebra, which prefers mountainous terrain, the term "Plains Zebra" for the species as a whole, with its various subspecies (and there is no agreement among scientists how many "subspecies" there are), is a much more sensible term than Burchell’s Zebra. Fortunately this usage seems to be favoured more and more. It will certainly gradually eliminate the enormous confusion that exists.
When it was realized that there are far too many names for zebras, and many were consequently made synonyms, the Quagga was no longer there. How it was related to the other zebras, was not certain. So, one left it as a species (as it had been described, after all), and called the few zebra subspecies that live on the plains, "Burchell’s Zebras".
Then there was, of course, the Mountain Zebra, and, in East Africa, the Grevy Zebra. Three living zebra species, and one extinct "species"? No one was certain about this. Some scientists tended to see the Quagga as a subspecies, others as a species. What is more, it was thought that the question about the Quagga’s taxonomic position could no longer be answered, because there were no more Quaggas around to be studied.
But then, in the early 1980’s, to everybody’s surprise, that question WAS answered, through the analysing of the Quagga’s DNA from tissue that was removed during the remounting of several of the stuffed original Quaggas in museums.
These developments are fairly new, and the results of the Quagga DNA analysis, namely that the Quagga WAS one of the Plains Zebra subspecies, not a species of its own, have not yet been absorbed everywhere, especially where people are not involved in Equid taxonomy.
Now, was the Quagga a subspecies of Burchell’s Zebra, or the other way around? That is simple, because if it is established that two former species names in fact refer to one and the same species, then the older of the two names takes precedence over the younger.
Equus quagga ---1788, Equus burchelli ---1824.
All plains zebras therefore, including the Quagga and the "true" Burchell’s Zebra (as it is sometimes called) are subspecies of Equus quagga. The Quagga’s full name is Equus quagga quagga; its immediate northern cousin was Equus quagga burchelli; the next subspecies in a northerly direction presently is Equus quagga antiquorum, etc.
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