Common blanket octopus

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Common blanket octopus
Tremoctopus violaceus Merculiano.jpg
Tremoctopus violaceus d'Orbigny.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Family: Tremoctopodidae
Genus: Tremoctopus
Species:
T. violaceus
Binomial name
Tremoctopus violaceus
Distribution of Tremoctopus violaceus Distribution of Tremoctopus violaceus.png
Distribution of Tremoctopus violaceus
Range of Tremoctopus violaceus [2]
Synonyms [3]
  • Octopus atlanticus
    D'Orbigny, 1834 in 1834–1847
  • Octopus gracilis
    Souleyet, 1852
  • Octopus koellikerii
    Verany, 1847
  • Octopus mycrostoma
    Reynaud, 1831
  • Octopus quoyanus
    D'Orbigny, 1834 in 1834–1847
  • Ocythoe velata
    Risso, 1854
  • Octopus velifer
    Ferussac, 1835 in 1834–1848
  • Tremoctopus joubini
    Hoyle, 1909
  • Tremoctopus lucifer
    Akimushkin, 1963
  • Tremoctopus microstomus
    (Reynaud, 1831)

The common blanket octopus or violet blanket octopus (Tremoctopus violaceus) [4] is a large octopus of the family Tremoctopodidae found worldwide in the epipelagic zone of warm seas. The degree of sexual dimorphism in this species is very high, with females growing up to two meters in length, whereas males grow to about 2.4 cm. The first live specimen of a male was not seen until 2002 off the Great Barrier Reef. Individual weights of males and females differ by a factor of about 10,000 and potentially more. [5]

Contents

Males and small females of less than 7 cm have been reported to carry with them the tentacles of the Portuguese man o' war. It is speculated that these tentacles serve both as a defensive mechanism and possibly as a method of capturing prey. This mechanism is no longer useful at larger sizes, which may be why males of this species are so small. The web between the arms of the mature female octopus serves as a defensive measure as well, making the animal appear larger, and being easily detached if bitten into by a predator. [6] The complete mitogenome of T. violaceus is a circular double-stranded DNA sequence that is 16,015 base-pairs long. [7]

Mating behaviour

The third right arm in male blanket octopus is called the hectocotylus, which has a sperm-filled pouch between the arms. When the male is ready to mate, the pouch ruptures, and sperm is released into the arm. He then cuts this arm off and gives it to a female. It is likely that the male dies after mating. The female stores the arm in her mantle to be used when she is ready to fertilize her eggs. She may store several hectocotyli from different males at once. [5]

Sexual dimorphism

The common blanket octopus exhibits one of the highest degrees of sexual size-dimorphism found in large animals. There are several theories as to why this developed. It is advantageous for females to be big; their large eggs take a lot of energy to maintain. The bigger a female is, the more eggs she can carry, and she can birth more offspring that could potentially survive to adulthood. Sperm does not require much energy or space to maintain, so males do not face the same pressure to be big. The use of the Portuguese man o' war tentacles is effective only in smaller animals. So selection may have favoured males to remain small in order to continue to utilize this defence mechanism. [5]

Defense mechanisms

Predators of the common blanket octopus include the blue shark, [8] tuna, [9] and the billfish. [9] Female blanket octopuses can roll up and unfurl their webbed blanket as needed. [10] The blanket serves to make the octopus look bigger, and the females can also sever the blanket off to distract predators. [11]

The male blanket octopuses was first observed to be using Portuguese man o' war stingers in 1963. The octopus has Portuguese man o' war tentacles attached to its four dorsal arms. It is unknown whether the blanket octopus is immune to the toxins in the stingers or if they only hold the stingers at insensitive tissue. The use of these tentacles could serve both as defensive and offensive mechanisms. The toxin from the Portuguese man o' war wards off predators, but it could also be used to catch prey. [12]

Related Research Articles

<span class="mw-page-title-main">Octopus</span> Soft-bodied eight-limbed order of molluscs

An octopus 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 center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.

<span class="mw-page-title-main">Cephalopod</span> Class of mollusks

A cephalopod is any member of the molluscan class Cephalopoda 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 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.

<span class="mw-page-title-main">Portuguese man o' war</span> Marine invertebrate found in the Atlantic and Indian Oceans

The Portuguese man o' war, also known as the man-of-war, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is considered to be the same species as the Pacific man o' war or bluebottle, which is found mainly in the Pacific Ocean. The Portuguese man o' war is the only species in the genus Physalia, which in turn is the only genus in the family Physaliidae.

<span class="mw-page-title-main">Giant squid</span> Deep-ocean dwelling squid in the family Architeuthidae

The giant squid is a species of deep-ocean dwelling squid in the family Architeuthidae. It can grow to a tremendous size, offering an example of abyssal gigantism: recent estimates put the maximum size at around 12–13 m (39–43 ft) for females and 10 m (33 ft) for males, from the posterior fins to the tip of the two long tentacles. The mantle of the giant squid is about 2 m long, and the length of the squid excluding its tentacles rarely exceeds 5 m (16 ft). Claims of specimens measuring 20 m (66 ft) or more have not been scientifically documented.

<span class="mw-page-title-main">Argonaut (animal)</span> Genus of cephalopods

The argonauts are a group of pelagic octopuses. They are also called paper nautili, referring to the paper-thin eggcase that females secrete. This structure lacks the gas-filled chambers present in chambered nautilus shells and is not a true cephalopod shell, but rather an evolutionary innovation unique to the genus. It is used as a brood chamber, and to trap surface air to maintain buoyancy. It was once speculated that argonauts did not manufacture their eggcases but utilized shells abandoned by other organisms, in the manner of hermit crabs. Experiments by pioneering marine biologist Jeanne Villepreux-Power in the early 19th century disproved this hypothesis, as Villepreux-Power successfully reared argonaut young and observed their shells' development.

<span class="mw-page-title-main">Bolitaeninae</span> Subfamily of octopuses

The Bolitaeninae are a subfamily, in the family Amphitretidae, of small, common pelagic octopuses found in all tropical and temperate oceans of the world. The taxonomy of this taxon is not entirely certain; recent research suggests just two genera exist, Bolitaena and Japetella, both of which are thought to be monotypic by some authorities and under this view, the family would represent two very similar species: Bolitaena pygmaea and Japetella diaphana. However, currently a second species of Bolitaena, B. massyae is also recognised.

<i>Ocythoe tuberculata</i> Species of cephalopods

Ocythoe tuberculata, also known as the tuberculate pelagic octopus or football octopus, is a pelagic octopus. It is the only known species in the family Ocythoidae.

<span class="mw-page-title-main">Spermatophore</span> Packet containing sperm in invertebrate reproduction

A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores may additionally contain nourishment for the female, in which case it is called a nuptial gift, as in the instance of bush crickets. In the case of the toxic moth Utetheisa ornatrix, the spermatophore includes sperm, nutrients, and pyrrolizidine alkaloids which prevent predation because it is poisonous to most organisms. However, in some species such as the Edith's checkerspot butterfly, the "gift" provides little nutrient value. The weight of the spermatophore transferred at mating has little effect on female reproductive output.

<span class="mw-page-title-main">Hectocotylus</span> Cephalopod sex organ

A hectocotylus is one of the arms of male cephalopods that is specialized to store and transfer spermatophores to the female. Structurally, hectocotyli are muscular hydrostats. Depending on the species, the male may use it merely as a conduit to the female, analogously to a penis in other animals, or he may wrench it off and present it to the female.

<span class="mw-page-title-main">Blanket octopus</span> Genus of cephalopods

Tremoctopus is a genus of pelagic cephalopods, containing four species that occupy surface to mid-waters in subtropical and tropical oceans. They are commonly known as blanket octopuses, in reference to the long, transparent webs that connect the dorsal and dorsolateral arms of the adult females. The other arms are much shorter and lack webbing.

<span class="mw-page-title-main">Cephalopod intelligence</span> Measure of cognitive ability of cephalopods

Cephalopod intelligence is a measure of the cognitive ability of the cephalopod class of molluscs.

<i>Argonauta hians</i> Species of mollusc

Argonauta hians, also known as the winged argonaut, muddy argonaut or brown paper nautilus, is a species of pelagic octopus. The common name comes from the grey to brown coloured shell. The Chinese name for this species translates as "Grey Sea-horse's Nest". The female of the species, like all argonauts, creates a paper-thin eggcase that coils around the octopus much like the way a nautilus lives in its shell. The eggcase is characterised by a wide keel that gives it a square appearance, few rounded tubercles along the keel, and less than 40 smooth ribs across the sides of the shell. The shell is usually approximately 80 mm in length, although it can exceed 120 mm in exceptional specimens; the world record size is 121.5 mm.

<i>Euprymna tasmanica</i> Species of mollusc

Euprymna tasmanica, also known as the southern dumpling squid or southern bobtail squid, is a bobtail squid that lives in the shallow temperate coastal waters of southern Australia's continental shelf. It lives for between 5 and 8 months and the adults can grow up to 6 or 7 cm long with a mantle length of 3 to 4 cm. They are found in seagrass beds or areas with soft silty or muddy bottoms from Brisbane on the east coast to Shark Bay on the west, as well as around Tasmania. Southern dumpling squid are nocturnal and during the day hide in sand or mud covered in a mucus-lined coat of sediment. If disturbed acid glans can quickly remove this coat as an additional decoy to ink squirting.

<i>Metasepia tullbergi</i> Species of cuttlefish

The paintpot cuttlefish is a small, poorly researched species of cuttlefish found in the Indo-Pacific, between Japan and Hong Kong. It is one of the two species classified in the genus Metasepia. Metasepia cuttlefish are characterized by their small, thick, diamond-shaped cuttlebone, and distinctive body coloration.

<i>Metasepia pfefferi</i> Species of cuttlefish

Metasepia pfefferi, also known as the flamboyant cuttlefish, is a species of cuttlefish occurring in tropical Indo-Pacific waters off northern Australia, southern New Guinea, as well as numerous islands of the Philippines, Indonesia and Malaysia.

<i>Velodona</i> Genus of octopuses

Velodona togata is a species of octopus in the monotypic genus Velodona. First described by Carl Chun in 1915, with a second subspecies discovered by Guy Coburn Robson in 1924, it was named for the distinctive membranes on its arms.

<span class="mw-page-title-main">Cephalopod limb</span> Limbs of cephalopod molluscs

All cephalopods possess flexible limbs extending from their heads and surrounding their beaks. These appendages, which function as muscular hydrostats, have been variously termed arms, legs or tentacles.

<span class="mw-page-title-main">Caribbean reef octopus</span> Species of cephalopod

The Caribbean reef octopus is a coral reef marine animal. It has eight long arms that vary in length and diameter. In comparison to the arms, the mantle is large and bulky. This species is difficult to describe because it changes color and texture to blend into its surroundings, using specialised skin cells known as chromatophores. Its color range is very large; it can change from crimson to green, and bumpy to smooth. It weighs around 3.3 lb or 1.5 kg.

<span class="mw-page-title-main">Spawn (biology)</span> Process of aquatic animals releasing sperm and eggs into water

Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, to spawn refers to the process of freely releasing eggs and sperm into a body of water ; the physical act is known as spawning. The vast majority of non-mammalian, non-avian and non-reptilian aquatic and/or amphibious lifeforms reproduce through this process, including the:

<span class="mw-page-title-main">Sepioloidea lineolata</span> Species of cuttlefish

Sepioloidea lineolata or more commonly known as the striped pyjama squid or the striped dumpling squid is a type of bottletail squid that inhabits the Indo-Pacific Oceans of Australia. Although traditionally falling within Sepiida, the cuttlefish order, it lacks a cuttlebone. More recent phylogenomic evidence suggests bottletail and bobtail squid may form their own order, Sepiolida. The striped pyjama squid lives on the seafloor and is both venomous and poisonous. When fully mature, a striped pyjama squid will only be about 7 to 8 centimetres in length. Baby striped pyjama squid can be smaller than 10 millimetres (0.39 in).

References

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  7. Yuh-Wen Chiu; Chih-Wei Chang; Kang-Ning Shen; Yu-Min Ju; Hung-Du Lin (2018). "Complete mitochondrial genome and the phylogenetic position of the pelagic octopus Tremoctopusviolaceus (Mollusca: Tremoctopodidae)". Mitochondrial DNA Part B. 3 (2): 1248–1249. doi: 10.1080/23802359.2018.1532347 . PMC   7799641 . PMID   33474480.
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  10. "The Blanket Octopus and it's AMAZING Blanket!!". YouTube. 2019.
  11. Thomas, Ronald F. (1977). "Systematics, Distribution, and Biology of Cephalopods of the Genus Tremoctopus (Octopoda: Tremoctopodidae)". Bulletin of Marine Science. 27 (3): 353–392.
  12. Jones, Everet C. (1963-02-22). "Tremoctopus violaceus Uses Physalia Tentacles as Weapons". Science. 139 (3556): 764–766. Bibcode:1963Sci...139..764J. doi:10.1126/science.139.3556.764. ISSN   0036-8075. PMID   17829125. S2CID   40186769.

Further reading