The many chambers of their shells likely helped these cephalopods glide through the planet’s warm, shallow seas. A thin, tubelike structure called a siphuncle pumped air through the interior ...

Ammonites were shelled cephalopods that died out about 66 million years ago. Fossils of them are found all around the world, sometimes in very large concentrations. The often tightly wound shells of ...

Tusoteuthis was a giant squid nearly equal in size to those that ply the oceans today—with their tentacles stretched out, the ancient cephalopods may have measured 25 to 35 feet (8 to 11 meters ...

According to the study, early mosasaurids, including basal species, had relatively simple teeth adapted for consuming small prey such as fish and soft-bodied cephalopods. “Early, basal ...