Capricious subspeciation in the plains zebra, part 2: a new suggestion re the extinct quagga

What if inappropriate founders were chosen for the Quagga Revival Project, based on incorrect assumptions?

Please see my last two Posts.

The idea behind the Quagga Revival Project has been that any capacity for re-expression of the phenotype of the extinct E. q. quagga would likely occur in the geographically adjacent subspecies, namely Equus quagga burchellii. And so individuals were chosen and captured from populations of E. q. burchellii, starting the process of selective breeding.

However, E. q. burchellii has an oddly disjunct distribution: Zululand vs northern Namibia-southwestern Angola. These areas are 1600 km apart, and the southeasternmost sites are twice as far from the equator (30 vs 14 degrees South) as the northwesternmost sites. What if these two populations are significantly different genetically, with that in Zululand having the most in common (albeit not necessarily expressed in the wild phenotype) with the extinct quagga?

In order to see that northern Namibia might have been an unsuitable source of founders - because it is so far from the distribution of the extinct quagga - we must for a moment discount any taxonomic controversy.

Whether we call the northern Namibian population burchellii or not, this population apparently extended northwards to about 14 degrees South, in southwestern Angola (see file:///C:/Users/Antoni%20Milewski/Downloads/Beja2019_Chapter_TheMammalsOfAngola%20(1).pdf). If so, then capturing individuals in the Etosha area, as was done for the Quagga Revival Project, meant resorting to a gene-pool living up to 2000 km from the nearest population of the extinct quagga.

Whether we call the Zululand population E. q. burchellii or not, this form lived at most a few hundred km from the nearest population of the extinct quagga, i.e. at least four times closer.

This is what I suspect.

Before European arrival, there were five genetically different types of the plains zebra in southern Africa south and west of the Zambezi River. Their ranges (see https://geology.com/world/south-africa-satellite-image.shtml) were:

1) Western Cape, Eastern Cape and the southern part of Northern Cape provinces, extending to southern Free State province (extinct quagga),

2) northern Free State province to northern Kwazulu-Natal province,

3) Mpumalanga and Limpopo provinces and northwards as far as northern Botswana (nobody quibbles with calling this E. q. chapmani),

4) North West province at the southern edge of the Kalahari (an extinct population from which the type specimens for both burchellii (see https://proxy.europeana.eu/90402/RP_T_1914_17_189?view=https%3A%2F%2Flh3.googleusercontent.com%2F3JVvYAinrEi1oFK84S6WTwm7OH1qI8RV6RGTqbvOZ86qiwActBN3TJ0GTIlNCIKdF1Sp9np0bvEsZdelndCHlgMTCQ%3Ds0&disposition=inline&api_url=https%3A%2F%2Fapi.europeana.eu%2Fapi and https://en.wikipedia.org/wiki/Burchell%27s_zebra) and its junior synonym antiquorum were collected), and

5) Namibia, extending to southwestern Angola.

Of these, the one geographically closest to the extinct quagga was 2).

If it were up to me to start the Quagga Revival Project from scratch, I would capture founders only in Zululand, and I would prioritise individuals with the darkest ground-colour rather than individuals with minimal striping on the legs and hindquarters. I would then breed selectively for overall darkness before trying to reduce the striping.

פורסם על-ידי milewski milewski, ספטמבר 09, 2021 12:22 לפנה"צ

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