Cephalopod
Sign in to saveA cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") 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.
AI overview
Cephalopods are marine animals that include squids, octopuses, cuttlefish, and nautiluses, and they're distinctive for having a prominent head with arms or tentacles that evolved from the foot of their molluscan ancestors. They're notable for their intelligence, their ability to squirt ink as a defense mechanism, and they're important enough to science that there's an entire branch of study dedicated to them called teuthology.
AI-generated from the Wikipedia summary — may contain errors.
Key dates
- Inception
- 400000000 BCE
via Wikidata · CC0
Wikidata facts
- Instance of
- taxon
- Parent taxon
- Conchifera
- Image
- Squid komodo.jpg
Show 6 more facts
- P105
- class
- P910
Article
43 sectionsContents
- Distribution
- Biology
- Nervous system and behavior
- Senses
- Vision
- Photoreception
- Hearing
- Use of light
- Coloration
- Chromatophores
- Adaptive value
- Origin
- Convergent evolution
- Ink
- Circulatory system
- Respiration
- Locomotion and buoyancy
- Octopus vs. squid locomotion
- Shell
- Head appendages
- Feeding
- Radula
- <span id="Renal appendage"></span> Excretory system
- Reproduction and life cycle
- Sexual maturity
- Fertilization
- Male–male competition{{anchor|Male-male_competition}}
- Mate choice
- Sexual dimorphism
- Embryology
- Development
- Evolution
- Genetics
- Phylogeny
- Taxonomy
- Suprafamilial classification of the ''Treatise on Invertebrate Paleontology''
- Shevyrev classification
- Cladistic classification
- In culture
- See also
- References
- Further reading
- External links
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") 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 700 kilograms (1,500 lb) heavy colossal squid, the largest extant invertebrate.