The park said the sea monster, also known as a hippocampus by carousel enthusiasts, was taken on Nov. 16, 1985. It said a handful of collectors had been keeping an eye out for it. Its location was ...

So, if Bill Manville and Gilbert Manter’s eyes had been deceiving them, and the footprints in the sand weren’t left by a sea monster, what exactly was happening on Nantucket that summer?

With serpentine necks, flippers and a mouth full of needle-sharp teeth, plesiosaurs have captured imaginations since ...