Temporal range: Late Cambrian – present;[1] possible Early Cambrian presence[2]
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Extant and extinct cephalopods; clockwise from top-left: common octopus (Octopus vulgaris), Caribbean reef squid (Sepioteuthis sepioidea), chambered nautilus (Nautilus pompilius), Orthosphynctes, Clarkeiteuthis conocauda, and common cuttlefish (Sepia officinalis)
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Mollusca
Subphylum:
Conchifera
Class:
Cephalopoda Cuvier, 1797
Subclasses
Nautiloidea sensu lato (paraphyletic)
Plectronoceratoidea † (paraphyletic)
Multiceratoidea † (paraphyletic?)
Nautiloidea sensu stricto
Endoceratoidea †
Orthoceratoidea † (paraphyletic)
Bactritoidea † (paraphyletic)
Ammonoidea †
Coleoidea
?Paracoleoidea † (disputed)
A cephalopod/ˈsɛfələpɒd/ is any member of the molluscan class Cephalopoda/sɛfəˈlɒpədə/ (Greek plural κεφαλόποδες, kephalópodes; "head-feet")[3] such as a squid, octopus, cuttlefish, or nautilus. 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. Fishers sometimes call cephalopods "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). Extant cephalopods range in size from the 10 mm (0.3 in) Idiosepius thailandicus to the 14 m (45.1 ft) colossal squid, the largest extant invertebrate.
^Wilbur, Karl M.; Trueman, E.R.; Clarke, M.R., eds. (1985), The Mollusca, vol. 11. Form and Function, New York: Academic Press, ISBN 0-12-728702-7
^Hildenbrand, Anne; Austermann, Gregor; Fuchs, Dirk; Bengtson, Peter; Stinnesbeck, Wolfgang (2021). "A potential cephalopod from the early Cambrian of eastern Newfoundland, Canada". Communications Biology. 4 (1): 388. doi:10.1038/s42003-021-01885-w. PMC 7987959. PMID 33758350.
^Queiroz, K.; Cantino, P. D.; Gauthier, J. A. (2020). Phylonyms: A Companion to the PhyloCode. CRC Press. p. 1843. ISBN 978-1-138-33293-5.
A cephalopod /ˈsɛfələpɒd/ is any member of the molluscan class Cephalopoda /sɛfəˈlɒpədə/ (Greek plural κεφαλόποδες, kephalópodes; "head-feet") such as...
The cephalopods have a long geological history, with the first nautiloids found in late Cambrian strata, and purported stem-group representatives present...
Cephalopod intelligence is a measure of the cognitive ability of the cephalopod class of molluscs. Intelligence is generally defined as the process of...
Cephalopod ink is a dark-coloured or luminous ink released into water by most species of cephalopod, usually as an escape mechanism. All cephalopods, with...
All extant cephalopods have a two-part beak, or rostrum, situated in the buccal mass and surrounded by the muscular head appendages. The dorsal (upper)...
All cephalopods possess flexible limbs extending from their heads and surrounding their beaks. These appendages, which function as muscular hydrostats...
Vertebrate Octopus Cephalopods, as active marine predators, possess sensory organs specialized for use in aquatic conditions. They have a camera-type...
Cephalopods, which include squids and octopuses, vary enormously in size. The smallest are only about 1 centimetre (0.39 in) long and weigh less than...
Cephalopod attacks on humans have been reported since ancient times. A significant portion of these attacks are questionable or unverifiable tabloid stories...
Coleoidea or Dibranchiata is one of the two subclasses of cephalopods containing all the various taxa popularly thought of as "soft-bodied" or "shell-less"...
ναυτίλος nautílos 'sailor') is an ancient pelagic marine mollusc of the cephalopod family Nautilidae. The nautilus is the sole extant family of the superfamily...
Cephalopod fins, sometimes known as wings, are paired flap-like locomotory appendages. They are found in ten-limbed cephalopods (including squid, bobtail...
outgrowths, as well as drags, wooden or not, readily conjure up the image of a cephalopod, making it a descriptive name initially. This idea seems to first have...
relatives. Cuttlefish, like other cephalopods, have sophisticated eyes. The organogenesis and the final structure of the cephalopod eye fundamentally differ from...
Nautiloids are a group of marine cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living Nautilus and Allonautilus...
divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most...
class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth...
Orthoceras is a genus of extinct nautiloid cephalopod restricted to Middle Ordovician-aged marine limestones of the Baltic States and Sweden. This genus...
The ectocochleate (externally shelled) cephalopods are the oldest known representatives of their class, dating back to the Cambrian period. Their aragonitic...
called squid despite not strictly fitting these criteria. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are...
Cephalopods, usually specifically octopuses, squids, nautiluses and cuttlefishes, are most commonly represented in popular culture in the Western world...
Examples of cephalopds Pain in cephalopods is a contentious issue. Pain is a complex mental state, with a distinct perceptual quality but also associated...
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