Its shell is strongly ribbed and is in the form of a widely open spiral .
Allocrioceras is an ammonoid cephalopod from the Turonian to Santonian stages of the Late Cretaceous , included in the turrilitoid family Anisoceratidae .
Allocrioceras ' shell is strongly ribbed and is in the form of a widely open spiral .
Allocrioceras is an ammonoid cephalopod from the Turonian to Santonian stages of the Late Cretaceous , included in the turrilitoid family Anisoceratidae .