A realistic approach to subspecies-identification in the springbok

@jakob @jwidness @tandala @bobby23 @tonyrebelo @alanhorstmann @michalsloviak @colin25 @oviscanadensis_connerties @rogerioferreira

Naturalists interested in the subspecies of the springbok (Antidorcas marsupialis) should read https://www.zobodat.at/pdf/Zeitschrift-Saeugetierkunde_46_0189-0197.pdf.

Although now forty years old, Groves (1981) is still the best reference on a topic which will probably never be resolved satisfactorily.

The basic problem is that zoologists failed to document the nominate subspecies.

The Karoo springbok (Antidorcas marsupialis marsupialis) occurred in Namaqualand, the Karoo, Eastern Cape, Free State, Gauteng, and the southern part of Northwest Province, with possible extensions into Mpumalanga, Limpopo, and even Kwazulu-Natal Provinces.

Despite the extreme abundance of this form, the museums of the world have virtually no study-skins and only a few skulls.

The Karoo springbok was, like the extinct quagga (Equus quagga quagga, https://en.wikipedia.org/wiki/Quagga), taken for granted until it was too late. Furthermore, far fewer specimens were collected scientifically than for the quagga.

We cannot know exactly what subspecies marsupialis looked like in its original, fully wild condition.

It is technically extinct because

  • artificial reintroductions failed to discriminate against subspecies hofmeyri of the Northern Cape, and then
  • there has been nearly a century of advertent and inadvertent selective breeding by farmers, partly to promote mutant genotypes.

Furthermore,

  • body size is too adaptable to mean much, and
  • the facial colouration varies individually in all the subspecies.

South Africa has thus lost its national mammal as a subspecific genetic entity. Even more unfortunately, we can never define what that entity was in the first place.

Our best guess, based on a south-north cline from the northeastern Karoo to Angola (Groves 1981), is that the springbok of the Klein Karoo and Eastern Cape

Groves found only 33 study-skins of the whole species of the springbok to examine in the museums of the world. And, ironically, 39% of these came from Angola and Kaokoland (https://en.wikipedia.org/wiki/Kaokoland), which remain so remote that iNaturalist still features few photos from these areas.

More particularly, we have an odd situation:

Subspecies angolensis is the best-represented of all the subspecies, in terms of study-skins (13 of the 33 specimens examined by Groves). Subspecies hofmeyri, south of the Kunene River, in Kaokoland, is also surprisingly well-represented, by 7 study-skins.

However, ssp. angolensis is so poorly represented photographically that, to this day, no photo shows clearly the darkness of colouration that Groves found, relative to ssp. hofmeyri.

The false notion that angolensis extends to northern Namibia, including Etosha, seems to have arisen in Cain et al. (2004) Mammalian Species no. 753 (which is freely available on the Web, but cannot be linked here for some technical reason).

Although ostensibly an authoritative summary of the springbok, Cain et al. (2004) misportrayed the subspecies by means of an erroneous distribution map.

In summary, the matter of subspecies has been botched in several different ways, not so?

My suggestion for iNaturalist:

  • for observations from Angola, assume angolensis;
  • for observations from northern Namibia, the Namib south of the Kunene River, Botswana, and the Kgalagadi Transfrontier Park, assume hofmeyri; and
  • for all other locations, just identify to species-level, because the subspecies-status has been irretrievably compromised.

Also see:

https://www.inaturalist.org/posts/53665-is-the-golden-springbok-a-semi-domestic-sport-or-a-throwback-to-an-extinct-species#

https://www.inaturalist.org/journal/milewski/69433-do-wildlife-photographers-have-a-blind-spot-for-adult-females-a-test-using-the-springbok#

Posted by milewski milewski, May 06, 2021 20:16

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