White-patch nautilus
Nautilus stenomphalus, also known as the white-patch nautilus, is a species of nautilus native to the Great Barrier Reef. N. stenomphalus is very similar to N. pompilius and may in fact represent a subspecies. It is separated by the absence of a thickened callus and the presence of white patches in the umbilical and shoulder regions of the shell. The sheaths of this species have scalloped edges compared with the smooth sheaths of N. pompilius. N. stenomphalus also differs slightly in hood ornamentation. The shell is usually up to around 180 mm in diameter, although the largest specimen ever recorded measured 201 mm.
N. stenomphalus are scavengers that utilize two chemosensory rhinophores, rod-shaped structures located below the eye, to locate dead meat and consuming low-nutrients from the ocean floor. They dwell in darker waters in depths up to 300 meters, though moving towards shallower waters to scavenge at night. Though possessing primitive eyes, N. stenomphalus predominantly rely on chemoreception in order to locate food in their habitat. N. stenomphalus share many morphological similarities with its close relative N. pompilius such as “zigzag” shell color pattern
Nautilus stenomphalus are pelagic molluscs belonging to the Nautilidae cephalopod family predominantly found across coral reefs along the Indo-Pacific region. N. stenomphalus is specifically known to inhabit the Great Barrier Reef, whereas other members
