Pacific Ocean, Bellybutton Nautilus, Nautilus macromphalus


The Bellybutton Nautilus (Nautilus macromphalus) is a species of nautilus native to the waters off New Caledonia, the Loyalty Islands, and northeastern Australia. The shell of this species lacks a callus, leaving the umbilicus exposed, in which the inner coils of the shell are visible. This opening constitutes approximately 15% of the shell diameter at its widest point.