Cassowaries, Emu

The Casuariiformes order consists of large, flightless birds, encompassing three species of cassowary and one species of emu, all native to Australia-New Guinea. Taxonomically, they are grouped into one or two families: Casuariidae for both cassowaries and emus, or Dromaiidae for the emu alone. These birds are adapted for running, with the number of recognized cassowary species reduced from nine to three due to minor differences. The fossil record for this group is sparse and includes some fascinating finds. For instance, Emuarius fossils blend characteristics of cassowaries and emus, and there have been misattributions like fossils initially identified as giant emus but later understood to be unrelated birds called mihirungs. Additionally, the South American Diogenornis was once considered a rhea but might belong to the Casuariiformes, extending this lineage's fossil range. Whether emus or cassowaries represent a more primitive form is debatable and awaits further analysis, potentially involving genome studies and considering plate tectonics. The taxonomy includes various species and subspecies of Casuarius and Dromaius, with numerous synonyms and different classifications based on features like casque shape. The modern emu, scientifically named Dromaius novaehollandiae, includes various now-extinct insular forms like the King Island emu, the Kangaroo Island emu, and the Tasmanian emu, in addition to the surviving mainland population.