The Mount Goliath Lorikeet, also called Lory, is one of four subspecies of the Papuan Lorikeet /Lory (Charmosyna papou). In addition to the nominate species, (Charmosyna papou papou), and the Mount Goliath (Charmosyna papou goliathina), are Stella's Lorikeet (Charmosyna papou stellae) and Charmosyna papou wahnesi.
All have slight variations in plumage and all come from Indonesia and Papua New Guinea. (Photos above and below are all of Mount Goliath subspecies of Papuan Lorikeet).
The Mount Goliath, together with the Stella and Wahnesi subspecies, has a melanistic form where most red and yellow becomes black (but green and blue remain).
The blue on the nape and rump remains.
The tail is longer than the bird.
A regular melanistic Mount Goliath Lory
This one got a little mixed up and retained its red rear.
All three melanistic versions dining together (with friends)
This one also got mixed up and introduced yellow barring on its green wings
Superficially similar to, but smaller than, the Mount Goliath Lorikeet/Lory is Josephine's Lorikeet, also called Josephine's Lory.
Also a Charmosyna species and also from Indonesia and Papua New Guinea. It is also superficially similar to the much smaller Fairy Lorikeet/Lory (link below).
Josephine's Lorikeet tends to have a slightly greyer crown and wider grey bare skin around the eyes than the Papuan (Mount Goliath) Lorikeet. It also has red on top of the much shorter tail (accounts for much of the difference in overall length).