The Full Wiki

More info on Orthoconic

Orthoconic: Wikis


Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.


(Redirected to Orthocone article)

From Wikipedia, the free encyclopedia

Fossilised Orthoceras orthocones.

An orthocone is a usually long straight shell of a nautiloid cephalopod. During the 18th and 19th centuries, all shells of this type were named Orthoceras, but it is now known that many groups of nautiloids developed or retained this type of shell.

An orthocone can be thought of as like a Nautilus shell, but with the shell straight and uncoiled. It was previously believed that these represented the most primitive form of nautiloid, but it is now known that the earliest nautiloids had shells that were slightly curved. An orthoconic form evolved several times among cephalopods, and among nautiloid cephalopods is prevalent among the ellesmerocerids, endocerids, actinocerids, orthocerids, and bactritids.

Orthocones existed from the Late Cambrian to the Late Triassic, but they were most common in the early Paleozoic. Revivals of the orthocone design later occurred in other cephalopod groups, notably baculitid ammonites in the Cretaceous Period. Orthocone nautiloids range in size from less than an inch to (in some giant endocerids of the Ordovician) seventeen feet (or five meters) long.


Got something to say? Make a comment.
Your name
Your email address