Fig. 1From: Nautilus: biology, systematics, and paleobiology as viewed from 2015 Nautilus pompilius, Vanuatu. This population swims to near surface depths. It is recognized by having the highest percent pigmentation of N. pompilius. Of all nautiluses, only N. macromphalus has the same degree of pigmentation on shell (as a percentage of shell area when viewed from the side). Like the Vanuatu population, N. macromphalus comes to near-surface depths. All deeper water nautiluses show less pigmentation. The only difference between N. pompilius and N. macromphalus is the absence of an umbilical plug and a slightly higher D shell-coiling statistic. Photo P.D. WardBack to article page