Taxonomy
There was long confusion regarding the taxonomic status and geographic origin of the King Island Emu, particularly with respect to their relationship to the Kangaroo Island Emu, specimens of which were also transported to France as part of the same French expedition to Australia in the early 1800s. The logbooks of the expedition failed to clearly state where and when the small Emu individuals were collected, and this has resulted in a plethora of scientific names subsequently being erected for either bird, many on questionable grounds, and the idea that all specimens had originated from Kangaroo Island. The French also referred to both Emus and cassowaries as "Casoars" at the time, which has lead to some confusion.
Louis Jean Pierre Vieillot first coined the binomial Dromaius ater in 1817. In 1906, Walter Baldwin Spencer coined the name Dromaius minor based on some Pleistocene sub-fossil bones and egg-shells found on King Island the same year, believing they were the first physical evidence of an Emu from there. In his 1907 book Extinct Birds, Walter Rothschild claimed Vieillot's description actually referred to the Australian Emu, and that the name D. ater was therefore preoccupied. Believing the skin in Muséum national d'Histoire naturelle of Paris was from Kangaroo Island, he made it the type specimen of his new species Dromaius peroni, named after the French naturalist François Péron, who is the main source of information about the bird in life. The Australian amateur ornithologist Gregory Mathews coined further names in the early 1910s, including a new genus name, Peronista, as he believed the King and Kangaro Island birds were generically distinct from the mainland Emu. Later writers claimed that the subfossil remains found on King and Kangaroo island were not discernibly different, and that they therefore belonged to the same taxon.
In 1959, the French ornithologist Christian Jouanin proposed that none of the skins were actually from Kangaroo Island. In 1990, Jouanin and Jean-Christophe Balouet demonstrated that the mounted skin in Paris came from a King Island, and that at least one live bird had been brought from each island. All scientific names given to the Kangaroo Island bird were therefore based on specimens from King Island or were otherwise invalid, leaving it nameless. More recent finds of sub-fossil material and subsequent studies on King and Kangaroo Island Emu, notably by Shane A. Parker in 1984, confirmed their separate geographic origin and distinct morphology. Parker named the Kangaroo Island bird Dromaius baudinianus, after the leader of the French expedition.
There are few morphological differences that distinguish the extinct insular Emus from the modern Emu besides their size, but all three taxa were most often considered distinct species. A 2011 genetic study of nuclear and mitochondrial DNA, which was extracted from five sufossil King Island Emu bones, showed that its genetic variation fell within that of the extant mainland Emus. It was therefore interpreted as conspecific with the Emus of the Australian mainland, and was reclassified as a subspecies of Dromaius novaehollandiae; D. n. ater. Other animals present on King Island are also considered as subspecies of their mainland or Tasmanian counterparts rather than distinct species. The authors suggested that further studies using different methods might be able to find features which distinguish the taxa.
Read more about this topic: Dark Emu