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| Argonauts Temporal range: Miocene – Recent | |
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| Eggcases of various Argonauta species | |
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| Family: | Argonautidae |
| Genus: | Argonauta Linnaeus, 1758 |
Argonauta, the argonauts, is the only living genus in the Argonautidae family. They are a group of pelagic octopods.
They are also called paper nautiluses, because of the paper-thin eggcase that females make. This structure does not have the gas-filled chambers of nautilus shells, and is not a true cephalopod shell. It is an evolutionary innovation unique to the genus Argonauta.
Argonauts are found in tropical and subtropical waters worldwide: they live in open ocean. Like most octopods, they have a rounded body, eight arms and no fins. However, unlike octopuses, argonauts live close to the sea surface rather than on the seabed. Argonauta species have very large eyes and small distal webs. They have a mantle-funnel locking apparatus, which is a way to identify the genus. It consists of knob-like cartilages in the mantle and corresponding depressions in the funnel. Unlike the closely related genera Ocythoe and Tremoctopus, Argonauta species lack water pores.
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