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Cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symmetry, bilateral body symmetry, a prominent head, and a set of cephalopod arm, arms or tentacles (muscular hydrostats) modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt Cephalopod ink, 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 taxon, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by ''Nautilus (genus), Nautilus'' and ''Allonautilus''. In the Coleoidea, the molluscan shell has been internalized or is absent, where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautiloid
Nautiloids are a group of cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and species rich, with over 2,500 recorded species. They flourished during the early Paleozoic era, when they constituted the main predatory animals. Early in their evolution, nautiloids developed an extraordinary diversity of shell shapes, including coiled morphologies and giant straight-shelled forms ( orthocones). No orthoconic and only a handful of coiled species, the nautiluses, survive to the present day. In a broad sense, "nautiloid" refers to a major cephalopod subclass or collection of subclasses (Nautiloidea ''sensu lato''). Nautiloids are typically considered one of three main groups of cephalopods, along with the extinct ammonoids (ammonites) and living coleoids (such as squid, octopus, and kin). While ammonoids and coleoids are monophyletic clades with exclusive ancestor-desce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octopus
An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the centre point of the eight limbs. An octopus can radically deform its shape, enabling it to squeeze through small gaps. They trail their appendages behind them as they swim. The siphon is used for respiration and locomotion (by water jet propulsion). Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse invertebrates. Octopuses inhabit various ocean habitats, including coral reefs, pelagic waters, and the seabed; some live in the intertidal zone and others at abyssal depths. Most species grow quickly, mature early, and are short-lived. In most species, the male uses a speciall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cuttlefish
Cuttlefish, or cuttles, are Marine (ocean), marine Mollusca, molluscs of the order (biology), suborder Sepiina. They belong to the class (biology), class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal mollusc shell, shell, the cuttlebone, which is used for control of buoyancy. Cuttlefish have large, W-shaped pupils, eight Cephalopod arm, arms, and two tentacles furnished with :wikt:denticulate, denticulated suckers, with which they secure their prey. They generally range in size from , with Cephalopod size, the largest species, the giant cuttlefish (''Sepia apama''), reaching in mantle (mollusc), mantle length and over in mass. Cuttlefish eat small molluscs, crabs, shrimp, fish, octopuses, worms, and other cuttlefish. Their predators include dolphins, larger fish (including sharks), seals, seabirds, and other cuttlefish. The typical life expectancy of a cuttlefish is about 1–2 years. Studies are said to indicate cuttlefis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus
A nautilus (; ) is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina. It comprises nine living species in two genera, the type genus, type of which is the genus ''Nautilus (genus), Nautilus''. Though it more specifically refers to the species ''chambered nautilus, Nautilus pompilius'', the name chambered nautilus is also used for any of the Nautilidae. All are protected under CITES CITES Appendix II, Appendix II. Depending on species, adult shell diameter is between . The Nautilidae, both extant and extinct, are characterized by involute or more or less convoluted shells that are generally smooth, with compressed or depressed whorl (mollusc), whorl sections, straight to sinuous Suture (anatomy), sutures, and a tubular, generally central siphuncle.Kümmel, B. 1964. Nautiloidae-Nautilida, in the Treatise on Invertebrate Paleontology, Geological Society of America and Univ of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squid
A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also called ''squid'' despite not strictly fitting these criteria). Like all other cephalopods, squid have a distinct head, Symmetry (biology)#Bilateral symmetry, bilateral symmetry, and a mantle (mollusc), mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius (cephalopod), gladius or pen, made of chitin. Squid diverged from other cephalopods during the Jurassic and occupy a similar Ecological niche, role to teleost fish as open-water predators of similar size and behaviour. They play an important role in the open-water food web. The two long tentacles are used to grab prey and the eight arms to hold and control it. The beak then cuts the food into suitable size chunks for swal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coleoidea
Coleoidea or Dibranchiata is one of the two subclasses of cephalopod molluscs containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus, squid and cuttlefish). Unlike its extant sister group Nautiloidea, whose members have a rigid outer shell for protection, the coleoids have at most an internal shell called cuttlebone or gladius that is used for buoyancy or as muscle anchorage. Some species, notably incirrate octopuses, have lost their internal shell altogether, while in some it has been replaced by a chitinous support structure. The major divisions of Coleoidea are based upon the number of arms or tentacles and their structure. The extinct and most primitive form, the Belemnoidea, presumably had ten equally-sized arms in five pairs numbered dorsal to ventral as I, II, III, IV and V. More modern species either modified or lost a pair of arms. The superorder Decapodiformes has arm pair IV modified into long tentacles w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopod Ink
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 the exception of the Nautilidae and the Cirrina (deep-sea octopuses), are able to release ink to confuse Predator, predators. The ink is released from the ink sacs (located between the gills) and is dispersed more widely when its release is accompanied by a jet of water from the Siphon (molluscs)#The hyponome of cephalopods, siphon. Its dark colour is caused by its main constituent, melanin. Each species of cephalopod produces slightly differently coloured inks; generally, octopuses produce black ink, squid ink is blue-black, and cuttlefish ink is sepia (color), a shade of brown. A number of other aquatic molluscs have similar responses to attack, including the gastropod clade known as sea hares. Properties and chemistry Cephalopod ink contains a number of chemicals in a variety of different concentrations, depending on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The number of additional fossil species is estimated between 60,000 and 100,000, and the proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine biology, marine phylum, comprising about 23% of all the named marine organisms. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat, as numerous groups are freshwater mollusc, freshwater and even terrestrial molluscs, terrestrial species. The phylum is typically divided into 7 or 8 taxonomy (biology), taxonomic class (biology), classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurobiology, neurologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonoidea
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family Nautilidae). The earliest ammonoids appeared during the Emsian stage of the Early Devonian (410.62 million years ago), with the last species vanishing during or soon after the Cretaceous–Paleogene extinction event (66 million years ago). They are often called ammonites, which is most frequently used for members of the order Ammonitida, the only remaining group of ammonoids from the Jurassic up until their extinction. Ammonoids exhibited considerable diversity over their evolutionary history, with over 10,000 species having been described. Ammonoids are excellent index fossils, and they have been frequently used to link rock layers in which a particular species or genus is found to specific Geologic time scale, geologic time periods. Their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endoceratoidea
Endocerida, from Ancient Greek ἔνδον (''éndon''), meaning "inside", and κέρας (''kéras''), meaning "horn", is an extinct Nautiloidea, nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in their siphuncle. Endocerida was a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silurian. Their shells were variable in form. Some were straight (orthoconic), others curved (cyrtoconic); some were long (longiconic), others short (breviconic). Some long-shelled forms like ''Endoceras'' attained shell lengths close to . The related ''Cameroceras'' is anecdotally reported to have reached lengths approaching , but these claims are problematic. The overwhelming majority of endocerids and nautiloids in general are much smaller, usually less than a meter long when fully grown. Morphology Endocerids had a relatively small body chamber as well as a proportionally large siphuncle, which in some genera reached nea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bactritoidea
The Bactritida are a small order of more or less straight-shelled (orthoconic) cephalopods that first appeared during the Emsian stage of the Devonian period (407 million years ago) with questionable origins in the Pragian stage before 409 million years ago, and persisted until the Carnian pluvial event in the upper middle Carnian stage of the Triassic period (231 million years ago). They are considered ancestors of the ammonoids, as well as of the coleoids (octopus, squid, cuttlefish, and the extinct belemnites). Bactritids are distinguished from the more primitive nautiloids by the small size and globular shape of the protoconch, the so-called embryonic shell. Nautiloids have relatively large embryonic shells, and living species lay a few large eggs. In contrast, bactritids and ammonoids produced large numbers of small eggs, each housing a small embryonic shell. Classification and description Bactritida (Erben 1964) are characterized by orthoconic to cyrtoconic shells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Octopus
The common octopus (''Octopus vulgaris'') is a Mollusca, mollusk belonging to the class Cephalopoda. ''Octopus vulgaris'' is one of the most studied of all octopus species, and also one of the most intelligent. It ranges from the eastern Atlantic, extends from the Mediterranean Sea, Black sea and the southern coast of England, to the southern coast of South Africa. It also occurs off the Azores, Canary Islands, and Cape Verde, Cape Verde Islands. The species is also common in the Western Atlantic. Characteristics ''Octopus vulgaris'' grows to in mantle (mollusc), mantle length with arms up to long.Norman, M.D. 2000. ''Cephalopods: A World Guide''. ConchBooks. It lives for 1–2 years and may weigh up to . Mating may become sexual cannibalism, cannibalistic. ''O. vulgaris'' is caught by bottom trawls on a huge scale off the northwestern coast of Africa. More than are harvested annually. The common octopus hunts at dusk. Crabs, crayfish, and bivalve mollusks (such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
