Typically, two distinct but very similar species of mulgara have been recognized: the
brush-tailed mulgara (
D. blythi) and the
crest-tailed mulgara or ampurta (
D. hillieri, recently resurrected from synonymy with
D. cristicauda). The brush-tailed mulgara has a relatively uncrested tail, two upper premolars, and six nipples. The crest-tailed mulgara has a crested tail, three upper premolars, and eight nipples. Recently, three additional species have been described: the
southern mulgara (
D. archeri), the
little mulgara (
D. marlowi), and the
northern mulgara (
D. woolleyae). The question remains as to why some widely co-occurring and similarly-sized
Dasycercus species would have gone extinct, since European colonisation, but others (i.e. the brush-tailed mulgara) have remained relatively common. The most distinguishing feature in identifying the two extant species is the crest of hair on the tail. The crest-tailed mulgara has a crest of long black hairs on the upper side of the distal end of the tail, although this feature may be present in
D. cristicauda,
D. archeri,
D. hillieri and
D. woolleyae. The brush-tailed mulgara has a brush of black hairs along the final two-thirds of the tail, though this is now no longer considered a unique feature. The species also have a slightly different dental formation, which is difficult to observe in live animals, and the brush-tailed mulgara has six nipples while the crest-tailed mulgara has eight. == Diet ==