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While subspecies taxonomy of Elephas maximus has varied among authors, the most recent treatment (Shoshani and Eisenberg 1982) recognizes three subspecies: E. m. indicus on the Asian mainland, E. m. maximus on Sri Lanka, and E. m. sumatranus on the Indonesian island of Sumatra. Borneo's elephants have traditionally been included in E. m. indicus (Shoshani and Eisenberg 1982) or E. m. sumatranus (Medway 1977; but see Fernando et al. 2003 and Cranbrook et al. 2008 for discussion of whether the elephants of Borneo are indigenous to the island). These subspecies designations were based primarily on body size and minor differences in coloration, plus the fact that E. m. sumatranus has relatively larger ears and an extra pair of ribs (Shoshani and Eisenberg 1982). The Sri Lankan subspecies designation was weakly supported by analysis of allozyme loci (Nozawa and Shotake 1990), but not by analysis of mitochondrial DNA (mtDNA) sequences (Hartl et al. 1996, Fernando et al. 2000, Fleischer et al. 2001, Vidya et al. 2009). However, current patterns of mtDNA variation suggest that the Sumatran subspecies is monophyletic (Fleischer et al. 2001), and consequently this taxon could be defined as an evolutionarily significant unit (ESU). This suggests that Sumatran elephants should be managed separately from other Asian Elephants in captivity, and is also an argument for according particularly high priority to the conservation of Sumatran elephants in the wild. Borneo's elephants have traditionally been included within Elephas maximus indicus (Shoshani and Eisenberg 1982) or Elephas maximus sumatranus (Medway 1977 …