Orthocycloceras, from Ancient Greek ὀρθός (orthós), meaning "straight", κύκλος (kúklos), meaning "circle", and κέρας (kéras), meaning "horn", is an extinct genus of actively mobile carnivorous cephalopods, essentially a nautiloid, that lived in what would be Europe during the Silurian to Devonian from 428.2 to 412.3 mya, existing for approximately .PaleoBiology Database: Orthocycloceras, basic info
Taxonomy Orthocycloceras was assigned to Orthocerida Sepkoski (2002).J. J. Sepkoski. 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363:1-560
Morphology The shell is usually long, and may be straight ("orthoconic") or gently curved. In life, these animals may have been similar to the modern squid, except for the long shell.
Fossil distribution Fossil distribution is exclusive to Sardinia and Austria.
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