Admin note: Please find to follow a series of artistic reconstructions of important and varied nautiloid, ammonoid and ammonite genera. The images were obtained from this Japanese website but the brief descriptive text I have compiled from a number of varied sources. These images are simply too excellent not to use in this context. I have placed the species in approximate chronological order and provided dates where possible. Those forms that I have provided a single date for rather than a range of dates does not mean that that species was very short-lived, but rather I have been unable to establish a date range, I will update this as and when I can. Please note that the soft-bodied animal depicted in the drawings is by no means definitive and is conjectural, (e.g. number of arms, colour, presence of a hood etc) but they do provide an excellent suggestion of what these ancient shelled cephalopods may have looked like. (Given my absolute lack of Japanese language ability and an appropriate keyboard, if any kind TONMO volunteer would like to notify the Japanese webmaster of this thread I would be most greatful. Also, I have made this thread sticky as it would be a pity for it to disappear down the forum as it has taken many hours to compile. In addition, I have locked it so that we can keep it to purely a list of species and descriptions. That way we can add more at a future date without sandwiching them between discussion threads.) If anyone would like to discuss any of the fossil cephalopods listed, please do so in this thread: Discussion of the Reconstructions of Nautiloids and Ammonoids Many thanks, hope you enjoy it, Phil Endoceras (nautiloid) Ordovician 485-458mya Order: Endoceratida Family: Endoceratidae The first ancient cephalopod in our list is represented by this depiction of the giant nautiloid Endoceras. The shell of Endoceras is absolutely typical of the orthoconic nautiloids and consists of a characteristic long conical shell composed of a series of interlinked cones (endocones) connected with a sub-ventral siphuncle. Due to the size and fragility of the shell, complete large fossils are unknown, but fragments are commonly found that have been projected to huge sizes. Endoceras probably reached at least 3.5m in length, but some other members of the Endoceratidae (e.g Cameroceras see below) may have reached much larger sizes. Such a shell shape allowed Endoceras to cut through the water at great speed as it would have minimised drag, though it may have not been especially manouverable. It represents the top predator of its time, and probably fed on trilobites and other small shelly creatures. It had a worldwide distribution, but is mostly known from North America and Sweden, deposits of this fossil are known as ‘Orthoceras Limestone’ and often used for a resilient flooring material. The Endoceratida were the first of the nautiloid orders to go extinct. To learn more about Endoceras, click here. Cameroceras (nautiloid) Ordovician 485-458mya Order: Endoceratida Family: Endoceratidae A close relative of Endoceras, this gigantic cephalopod is certainly one of the very largest cephalopods that has ever existed. It's shell is thought to have reached up to 11m in length. The top predator of it's time, Cameroceras failed to survive the Middle Ordovician. Due to it's immense bulk, Cameroceras is not thought to have been a very fast or manoeverable swimmer, and it probably drifted over the sea floor rooting out sea scorpions and tribolites with its arms. Fossils are restricted to North America and Europe.