Southern white rhino at Marwell Wildlife, photographed c 2003. They argue that ‘taxonomic inflation’ is an unfair term given the positive taxonomic neglect that has afflicted the animals concerned and show how, time and time again, taxa have suffered – both as subjects of conservation and management priority, and via the consequences of outbreeding depression in captivity – from a lack of research and from a priori assumptions. (2017) for a modern critique of the taxonomic inflation argument. One could, of course, write a whole essay on this issue I’m trying to avoid doing so here, and I’d point those interested to Gippoliti et al. The populations concerned are often at least as distinct as other species that are universally regarded as ‘good’, and the fact that we tend not to regard them as species in the first place is due to a mid-20th century phase of mass laissez-fair lumping and taxonomic inertia more than to actual analysis (many of the populations concerned were described as distinct species, then uncritically lumped in a few influential reviews due to the existence of hybrid and intermediate populations, and then assumed thereafter to be part of a single super-variable species). I tend to be ambivalent about all the recently proposed splits in extant mega-mammals – take it or leave it, to be frank – but I mostly find the case for splitting to be pretty good. Credit: Fabio b Wikimedia (CC BY-SA 2.5)Īs, of course, we all know, this is the issue that just won’t go away. 2013, Zachos 2014), and that a biological species definition is better and justified by hybridisation data anyway, and (5) that the split is inconvenient and irksome, and merely symptomatic of a rash ‘taxonomic inflation’ phase ( Meiri & Mace 2007)… who needs 58 bushbuck species when 1 species with 58 subspecies does the job just as well? Map showing historical ranges of the two white rhino taxa, though Ceratotherium was, of course, far more widely distributed in the geological past. 2013) and easily accommodated within a species, (4) that the PSC underlying these decisions is problematic and inconsistent (Zachos et al. 2013), (3) that the variation concerned is trivial (Heller et al. 2004), (2) that the evidence for the split is weak and even a bit of a joke when it comes to sample size (Heller et al. The responses to splittings of this sort include, variously, that (1) the split has only been made for conservation-mitigated reasons (Isaac et al. Southern white rhinos in captivity, at Marwell Wildlife, England. There are also reported differences between the two in behaviour and vocalisation. 2010) more specifically, between 750,000 and 1.5 million years ago. Genetic evidence indicates that the two forms diverged about 1 million years ago ( Groves et al. Southern white rhinos are also supposedly hairier on the body and ears. The two can be distinguished in virtually all measurements (pertaining to skull and tooth dimensions, limb bone lengths and so on), southern white rhinos are generally larger (males can be 2000-2400 kg as opposed to 1400-1600 kg), longer-bodied, have a longer palate, more concave skull roof, and more prominent grooves between their ribs and around the tops of their limbs while northern white rhinos seemingly are longer-limbed, have a straighter back, smaller, lower-crowned teeth and a straighter skull roof ( Groves et al. simum cottoni in ‘the north’ (by which I mean – historically – Uganda, South Sudan, Democratic Republic of Congo, Chad and Central African Republic). simum simum in the south of Africa, and C. Until recently, the consensus view was that white rhinos are one species ( Ceratotherium simum), consisting of two subspecies: C. A wooden installation that used to be on show at Marwell Wildlife, UK. A reminder of how big a white rhino is - specifically, a southern white rhino.
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