although previous genetic analyses have suggested that the quagga was genetically similar to plains zebras in mitochondrial DNA sequence (Higuchi et al. 1984, 1987), not all species of zebra were included in the comparison and genetic diversity in the quagga remained unknown. Morphological analyses of the quagga and all other zebra species have come to conflicting conclusions. In a study based on cranial measurements, the quagga was found to be as different from plains zebra as the plains zebra is from the mountain zebra (Klein & Cruz-Uribe 1999). Another study, based on pelage as well as cranial characters, found the quagga and the plains zebra to be highly similar and argued for subspecific status of the quagga (Groves & Bell 2004).