Western Zambian sable: Are they a Geographic Extension of the Giant sable Antelope?

Abstract

The giant sable (Hippotragus niger variani) is one of Africa's most spectacular large antelope. Years of civil unrest in Angola, a highly localized distribution and Interbreeding with its congener the roan antelope (H. equinus) has led to this subspecies being considered as critically endangered. Sable antelope occurring ∼600 km to the east in western Zambia superficially resemble giant sable in phenotype, prompting speculation in the popular media that the distribution of giant sable may be larger than currently documented. Our aim here was to Investigate the evolutionary placement of western Zambian sable using mitochondrial DNA control region data. Phylogenese analyses (maximum likelihood and Bayesian analyses) supported the monophyly of H. n. variant (Bayesian posterior probability of >0.95, bootstrap support >80%) and nested the western Zambian sable within H. n. niger. This finding was supported by an analysis of molecular variance that discretely grouped western Zambian sable from giant sable (ΦST = 0.645, P = 0.001). Significant genetic structure was also found across the range of H. n. nigera as Indicated by our phylogenetic analyses and analysis of molecular variance (ΦST = 0.418, P = 0.001). We conclude that although the western Zambian sable antelope and those of H. n. variani resemble one another in morphology, particularly with respect to facial markings, significant genetic differences underpin these two evolutionary lineages. Our findings hold Implications for the conservation of sable and highlight the need for active management Intervention.