'Lliving fossils' nautilus and allonautilus shaped by depths and diets over 500 million years

Nautilus and Allonautilus cephalopods and their extinct ancestors have been drifting through the mesophotic zone of the ocean for more than 500 million years. Researchers have spent the last 40 years trying to understand how these mysterious "living fossils" thrive in areas with limited nutrients. Nautilus and Allonautilus cephalopods and their extinct ancestors have been drifting through the mesophotic zone of the ocean for more than 500 million years. Researchers have spent the last 40 years trying to understand how these mysterious "living ... [795 chars]