Taking a lesson in evolutionary adaptation from octopus, squid

Cephalopods such as octopus and squid evolutionarily diverged from mollusks like slugs and snails. These animals have elaborate compact nervous systems located within specialized arm appendages, which can perform a surprisingly ...

How squid and octopus get their big brains

Cephalopods—which include octopus, squid, and their cuttlefish cousins—are capable of some truly charismatic behaviors. They can quickly process information to transform shape, color, and even texture, blending in with ...

Cephalopods: Older than previously thought?

Possibly the oldest cephalopods in the Earth's history stem from the Avalon Peninsula in Newfoundland (Canada) discovered by scientists from Heidelberg University. The 522-million-year-old fossils could turn out to be the ...

First gene knockout in cephalopod achieved

A team at the Marine Biological Laboratory (MBL) has achieved the first gene knockout in a cephalopod using the squid Doryteuthis pealeii, an exceptionally important research organism in biology for nearly a century. The ...

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Cephalopod

A cephalopod is any member of the molluscan class Cephalopoda (Greek plural Κεφαλόποδα (kephalópoda); "head-feet"). These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles (muscular hydrostats) modified from the primitive molluscan foot. Fishermen sometimes call them inkfish, referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology.

Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by Nautilus and Allonautilus. In the Coleoidea, the molluscan shell has been internalized or is absent, whereas in the Nautiloidea, the external shell remains. About 800 living species of cephalopods have been identified. Two important extinct taxa are the Ammonoidea (ammonites) and Belemnoidea (belemnites).

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