Brown et al. (pp. 63/64, if I counted correctly, - the page numbers on the PDF of the paper are “not for citation puposes”) suggest “that the giraffe might represent more than one species” and that their results and arguments “support viewing the giraffe as containing multiple distinct species rather than a single polymorphic form. Reciprocal monophyly in mtDNA sequences and nearly absolute partitioning in microsatellite data support minimally six species, corresponding to Giraffa peralta, G. rothschildii, G. reticulata, G. tippelskirchi, G. giraffa, and G. angolensis.” Also, “the Masai might constitute more than one species” and “additional taxa might be defined, pending analysis of the subspecies included in taxonomic schemes (Table 1) not sampled in our study design (e. g. G. c. antiquorum [10]). Finally many of these species appear to include multiple distinct population units that are genetically differentiated.”
