The Manus Island melomys is known only from Manus Island, Papua New Guinea. Camera records and captures in trees led authors to suggest it is largely arboreal, though it has also been trapped near the ground.
The paper measured two adult females at 162–165 mm head-and-body length, 175–180 mm tail length and 170–200 g. A photographed fresh individual appeared redder than older museum skins.
Early specimens came from cacao and sago palms, and cameras in 2013–2014 photographed animals in trees. The authors suggested strong arboreality, but later captures included sites near tree bases and under rattan.
An extinction-risk assessment has not been added yet.