I said the other day that I was going to have go all ‘text lite’ for a while. Here is my solution: a series of short posts, one per day, each of which features a different stuffed megamammal. Yes, welcome to day 1 of stuffed megamammal week. All of the stuffed megamammals you’re going to see were photographed in the excellent collection at the National Museum of Ireland, Dublin. So here we go.
This remarkable creature is a Hartebeest Alcelaphus buselaphus, and, specifically, it’s a female hartebeest belonging to the subspecies known as the Khama, Cape or Red hartebeest A. b. caama. Like so many subspecies, the Khama was originally regarded as a distinct species, and in fact still is by some. Those who do regard it as a species split it into two subspecies: A. caama caama (described in 1816 and extinct by 1940) and A. caama selbournei.
Though some controversy remains, it does now seem that the massive variation present among the many regional forms of hartebeest – about 70 taxa have been named, ranging across most of sub-Saharan Africa* – can all be accommodated within a single species, and indeed there are various hybrid zones where confusing intermediate morphologies are present (Ruxton & Schwarz 1929). Some authors – notably Jonathan Kingdon – regard Lichtenstein’s hartebeest or the Nkonzi as a subspecies of A. buselaphus, but most workers regard it as a separate species that even warrants it own ‘genus': Sigmoceros lichstensteinii. In overall shape, all hartebeest are alike: they are long-legged, short-necked alcephaline antelopes with tall shoulders and very long, narrow faces.
* And, previously, north of the Sahara too. The ‘original’ hartebeest, the nominate form of the species, is the now extinct Bubal A. b. buselaphus, a semi-desert specialist and the smallest of all the hartebeest. Formerly widespread across northern Africa, it was hunted to extinction by about 1923 (or perhaps a little later).
Hartebeest might be similar in shape, but they differ in colour (varying from dark red with black patches to light golden brown) and in horn shape. In some forms, the horns are widely spaced, relatively short and with backswept tips, while in others the horns have long, virtually conjoined bases (or pedicels) and curve outwards and then inwards at their tips, thereby forming tall, lyre-like shapes. In fact Dutch settlers thought that the shape of the horns resembled that of a heart, hence the common name. The adjacent photo shows some hartebeest horns I photographed in an antiques shop last year. I think they are Khama horns.
Kingdon (1997) proposed that the forms with the short horn bases, like the Kongoni A. b. cokei, Korkay A. b. swaynei and Tora A. b. tora (all of which are from eastern Africa), are more primitive than the tall-pedicelled forms like the Khama (of the Kalahari) and Kanki A. b. major (of western Africa). This has been mostly confirmed by DNA evidence (Flagstad et al. 2001, 2004) which indicates that hartebeest originated in eastern Africa and colonised the rest of the continent from there. DNA and fossil evidence also indicates that the extant alcelaphines (hartebeest, wildebeest, topi and kin) became extinct across most of their Pleistocene range and survived into the Holocene in just a few refugia: for hartebeest, two of these were north of the equator and one was south of it (Arctander et al. 1999, Flagstad et al. 2001). It is well known that alcelaphines are a very young clade (perhaps less than five million years old), and that, within their short history, they diversified rapidly. Data shows that their diversification events match key climatic changes, and in fact their evolution inspired Elisabeth Vrba to come up with the ‘turnover pulse’ hypothesis.
And… so much more to say, but I gotta stop there.
Refs – –
Arctander, P., Johansen, C. & Coutellec-Vreto, M. A. 1999. Phylogeography of three closely related African bovids (tribe Alcelaphini). Molecular Biology and Evolution 16, 1724-1739.
Flagstad, Ø, Olsaker, I. & Røed, K. H. 2004. The use of heterologous primers for analysing microsatellite variation in Hartebeest Alcelaphus buselaphus. Hereditas 130, 337-340.
– ., Syvertsen, P. O., Stenseth, N. C. & Jakobsen, K. S. 2001. Environmental change and rates of evolution: the phylogeographic pattern within the hartebeest complex as related to climatic variation. Proceedings of the Royal Society of London B 268, 667-677.
Kingdon, J. 1997. The Kingdon Field Guide to African Mammals. Academic Press, San Diego.
Ruxton, A. E. & Schwarz, E. 1929. On hybrid hartebeests and on the distribution of the Alcelaphus buselaphus group. Proceedings of the Zoological Society of London 38, 567-583.