other Phalangeroidea and primitive macropodines. These features discount all potoroids from being ancestors to the macropodids on these structural grounds. They consist of a compressed trigonid on the first lower molar, straight molar row and strongly twisted dentary. Primitive macropodines have the straight molar row in common. Ekaltadeta also has plesiomorphic features in that the dental canal and masseteric canal are separated anteriorly, below premolar three and the first molar, with the masseteric canal terminating in a cul-de-sac. This it shares with no other macropodids. Another feature that it only shares with Hypsipromnodon is that the lower second premolar is not evicted by the third premolar. Pleistocene developments Extinctions Balbaridae, Bulungamayinae, Sthernuridae all became extinct by the Pleistocene. The reason for their extinctions are unknown but hypotheses include outdated model, climate and habitat changes. Some species of Sthenurus could have been around when humans arrived in Australia, but by this time they were already progressing towards extinction.</ref> The taxonomic affiliations within the family and with other groups of marsupials is still in flux. Current speciation References Diprotodonts