Bigotites
Encyclopedia
Bigotites is strongly ribbed, round-whorled perisphinctid
Perisphinctaceae
Perisphinctoidea, formerly Perisphinctaceae, is a superfamily of Middle Jurassic to Lower Cretaceous ammonites, commonly with evolute shells with strong ribbing that typically divides about mid flank before crossing the venter....

 ammonitic cephalopod from the middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....

with a smooth band along the outer edge of the shell.
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