chambered nautilus - (nautilus pompilius)

allonautilus ammonite ancient cambrian cambrian-level cephalopod cephalopods chambered chambers counterparts created creation cretaceous deep depths endangered evolution fossil fossilized found headfoot identical jurassic living mesozoic meters modern mollusk nautilidae nautilus ocean oceans paleozoic pennsylvanian permian pompilius pompilus remains rock sea sediment sedimentary silurian strata tentacles triassic unchagnged virtually