A soft body that rapidly changes color and texture characterizes the family Octopodidae. An octopus has no skeleton and therefore is astonishingly compressible; Octopodidae can ooze through an opening no bigger than one of its eyeballs. Its incredible flexibility comes from its musculature, which consists of fibers that run in three directions, permitting it to change shape. Like all Mollusca, Octopodidae possesses a mantle. However, the mantle is fused with the cephalized head on the dorsal side. The "skin" of Octopodidae is equipped with chromatophores, which are pigment cells that an animal can expand or contract by muscular action. These cells vary in color, and as the animals expands some or contracts others, its color changes. The nervous system consisting of a well-developed brain, controls the color changes an Octopodidae makes in response to its moods and surroundings. The central nervous system of the octopus is the largest and most complex in the invertebrate world, rivaling that of many vertebrates, including mammals. Also analogous with the vertebrates, members of Octopodidae possess two large, complex eyes that are camera-like in structure, and their vision is acute. Although Octopodidae has a closed circulatory system like higher animals as well, the blood is a poor carrier of oxygen. As a result, Octopodidae tires easily. To stay alive, it relies on a system involving three hearts and permanently high blood pressure. A major distinguishing feature of Octopodidae is its eight muscular arms, which radiate out from the body around the beak-like jaws. In males, the third right arm is modified into a hectocotylus for mating. Each arm bears two rows of whitish suckers that can move independently. Each sucker may have 10,000 neurons to handle both taste and touch, and an octopus has thousands of suckers. Octopodidae has an ability to regenerate an injured or lost arm. It usually takes about 6 weeks for an arm to regenerate. It has been found that, along with arms, Octopodidae can even regenerate part of an eye that is damaged.
The blue-ringed octopi actually include four closely related species Hapalochochlaena marculsa, Hapalochochlaena lunulata, Hapalochochlaena fasciata, and Hapalochochlaena nierstraszi . Its larger rings distinguish Hapalochochlaena lunulata, the Greater blue-ringed octopus, from the other species. Hapalochochlaena lunulata is about 20 cm at maximum spread, but under normal circumstances, it appears much smaller than this. H. lunulata is dark brown to dark yellow in color, but with brilliant blue rings thought to be warning coloration that "glow" when it is angry. The reason the rings are blue is thought to be that the visual range of the octopus is most sensitive in the blue part of the spectrum. At the small beak at the junction of its eight arms rather than manufacturing ink, H. lunulata makes poison like the tetrodotoxin found in poisonous puffer fishes. Bacteria in their salivary glands produce it. The venom, contained in its saliva and designed to subdue or kill its prey is particularly lethal to human beings.
(Campbell 2000, Ellis 1991, Encarta 1998, Environment Australia 1999, Norman 1998, Roper and Hochberg 1988, Stewart 1997)
Range mass: 10 to 100 g.
Other Physical Features: ectothermic ; bilateral symmetry
-H. lunulata- is found in shallow coral and rock pools, particularly after storms, digging around for crabs. It tends to hide in crevices amongst rocks, inside seashells, and discarded bottles and cans because of its soft-bodied vulnerability. It is easy to identify the home of -H. lunulata - or any Octopodidae: The area immediately in front of the opening is littered with the shells and hollowed-out legs of various crustaceans. It occupies a particular nest for a long time and ventures forth only to hunt for food or look for a mate. However, it cannot resist a new nest when one is offered. They, as well as other Octopodidae, are bottom dwellers and are not found in open water. Although Octopodidae may venture onto dry land in pursuit of a crab, if it remains there Octopodidae is doomed: Within half an hour, it will die from suffocation.
(Campbell 2000, Ellis 1991, Encarta 1998, Environment Australia 1999, Stewart 1997)
Aquatic Biomes: reef ; coastal
Hapalochochlaena sp. are found in the IndoWest Pacific and Indian Oceans. They are very common in shallow waters around the coast of Australia particularly in the cooler areas along the southern coast. Hapalochochlaena lunulata specifically is found along the coasts of Northern Australia and farther north in the tropic western Pacific Ocean.
(Ellis 1991, Environment Australia 1999, Norman 1998, Roper and Hochberg 1988)
Biogeographic Regions: indian ocean (Native ); pacific ocean (Native )
H. lunulata is carnivorous, feeding primarily on fish, crabs, mollusks and other small marine animals. It hunts every thing that it is able to overpower. It ambushes prey from the background. H. lunulata often lures its victim by wiggling the tip of an arm like a worm; or it glides near and pounces on a crab, trapping the prey in its arms and dragging it towards its powerful beak-like jaws. Once it has bitten its prey, the octopus injects it with poisonous saliva to kill it. Either H. lunulata cracks prey open with its jaws or it disarticulates them, and with the tips of its arms, removes any vestige of the edible parts. H. lunulata does not employ its beak other than to take from the suckers the portions that it has removed.
(Hutchinson 1998, Ellis 1991, Encarta 1998, Environment Australia 1999)
Although other Octopodidae are used for biomedical research, behavioral research, and as gourmet food source, Hapalochochlaena sp. are too small and too dangerous for much. of these uses. Medical and psychological research are interested in the tetrodotoxin neurotoxin found in its venom for its aphrodisiac effect and its ability to block voltage-sodium channels so action potential in neurons is inhibited or reduced. They also have value as an unusual luxury item. As strange as it may seem, a H. lunulata individual was sold for $4000 at an auction in Sidney, Australia recently.
(Brenner and Elgar 1999, Ellis 1991, Melki 2000)
Poison from Hapalochochlaena sp. has proven to be fatal to humans especially to young children. There is no antivenom for this poison. Of the several human fatalities attributed to this animal, all have involved the animal being picked up. The bite itself may not even be felt. Five minutes or so later however, the victim may complain of dizziness and increasing difficulty in breathing. The powerful venom acts on the victim's voluntary muscles, paralyzing the muscles required for body movement and breathing. Artificial respiration is necessary to maintain life. The poison gradually wears off after 24 hrs, apparently leaving no side effects. (Campbell 2000, Environment Australia 1999, Norman 2000)
A male interested in mating approaches a female just close enough to stretch out a modified arm, the hectocotylus, and caress the female. This arm has a deep groove between the two rows of suckers and ends in a spoon-like tip. After a period of caressing the female with the tip of the hectocotylus, the male inserts its arm under the mantle of the female, and the spermatophores then travel down the groove on the hectocotylus to the female's oviduct. Soon after mating, the female begins to lay 60-100 eggs, which she carries in a cluster underneath her tentacles. She then guards them for the next 50 days. The eggs hatch into planktonic paralarvae and spend their first weeks as ocean plankton, drifting at the surface. After gaining weight, they drop to the bottom. Because she stops eating while brooding her eggs, the mother dies almost as soon as they hatch. The young are ready to reproduce around four months after hatching.
(Ellis 1991, Encarta 1998, Environment Australia 1999, Stewart 1997, Roper and Hochberg 1988)
Chobotnice kroužkovaná (Hapalochlaena lunulata), také známa jako chobotnice modrokroužkovaná, je druh chobotnice z rodu Hapalochlaena. Popsali jej Jean René Constant Quoy a Joseph Paul Gaimard v roce 1832.[1] Obývá mělké vody severního pobřeží Austrálie a v západním Tichomoří, za potravou se může krátkodobě vydat i na pevninu. Žije v různých trhlinách a její úkryt lze poznat podle zbytků kořisti v jeho blízkosti. Může jej obývat dlouhou dobu[2] a tráví v něm většinu svého času.[3]
Chobotnice kroužkovaná váží 10 až 100 g a měří maximálně 20 cm. Její tělo je tmavohnědé, případně tmavožluté,[2] v případě, že se chobotnice rozruší, se jí následkem reakcí buněk chromatoforů objeví na těle okolo šedesáti modrých kruhů zvýrazňovaných pohyby svalů.[3] Z celého rodu Hapalochlaena má tento druh největší skvrny. Nemá inkoustový váček.[2]
Druh je jedovatý, ve slinných žlázách je za pomocí bakteríí tvořen jed tetrodotoxin (TTX). Ten chobotnice využívá jak k lovu kořisti, kterou tvoří například krabi nebo ryby, které nejprve přiláká pohyby konců chapadel a potom smrtelně pokouše, tak k obraně. Samotné kousnutí je bezbolestné, ale nebezpečné i pro člověka; začne se projevovat po pěti minutách a postupně způsobí ochrnutí. Záchrana spočívá v umělém dýchání po dobu jednoho dne, než jed v těle vyprchá. Toxin je lékařsky zkoumán, uvažuje se o jeho použití jako afrodiziakum či uvolnění napětí v sodíkových kanálech.[2]
Druh je teritoriální a setkání preferuje pouze tehdy, kdy se chystá spářit. Páření probíhá tak, že samec speciálně upraveným chapadlem vloží do vejcovodu samice své spermie. Nedokáže však rozpoznat pohlaví zvířete, proto se někdy zkouší spářit i s ostatními samci.[4] Samice naklade 60 až 100 vajíček, o která se stará 50 dnů a po vylíhnutí mláďat umírá. Mláďata první týdny plavou společně s planktonem, teprve později se přesunou na dno. Rozmnožovat se mohou ve čtyřech měsících.[2]
Obrázky, zvuky či videa k tématu chobotnice kroužkovaná ve Wikimedia Commons
Chobotnice kroužkovaná (Hapalochlaena lunulata), také známa jako chobotnice modrokroužkovaná, je druh chobotnice z rodu Hapalochlaena. Popsali jej Jean René Constant Quoy a Joseph Paul Gaimard v roce 1832. Obývá mělké vody severního pobřeží Austrálie a v západním Tichomoří, za potravou se může krátkodobě vydat i na pevninu. Žije v různých trhlinách a její úkryt lze poznat podle zbytků kořisti v jeho blízkosti. Může jej obývat dlouhou dobu a tráví v něm většinu svého času.
Chobotnice kroužkovaná váží 10 až 100 g a měří maximálně 20 cm. Její tělo je tmavohnědé, případně tmavožluté, v případě, že se chobotnice rozruší, se jí následkem reakcí buněk chromatoforů objeví na těle okolo šedesáti modrých kruhů zvýrazňovaných pohyby svalů. Z celého rodu Hapalochlaena má tento druh největší skvrny. Nemá inkoustový váček.
Druh je jedovatý, ve slinných žlázách je za pomocí bakteríí tvořen jed tetrodotoxin (TTX). Ten chobotnice využívá jak k lovu kořisti, kterou tvoří například krabi nebo ryby, které nejprve přiláká pohyby konců chapadel a potom smrtelně pokouše, tak k obraně. Samotné kousnutí je bezbolestné, ale nebezpečné i pro člověka; začne se projevovat po pěti minutách a postupně způsobí ochrnutí. Záchrana spočívá v umělém dýchání po dobu jednoho dne, než jed v těle vyprchá. Toxin je lékařsky zkoumán, uvažuje se o jeho použití jako afrodiziakum či uvolnění napětí v sodíkových kanálech.
Druh je teritoriální a setkání preferuje pouze tehdy, kdy se chystá spářit. Páření probíhá tak, že samec speciálně upraveným chapadlem vloží do vejcovodu samice své spermie. Nedokáže však rozpoznat pohlaví zvířete, proto se někdy zkouší spářit i s ostatními samci. Samice naklade 60 až 100 vajíček, o která se stará 50 dnů a po vylíhnutí mláďat umírá. Mláďata první týdny plavou společně s planktonem, teprve později se přesunou na dno. Rozmnožovat se mohou ve čtyřech měsících.
The greater blue-ringed octopus (Hapalochlaena lunulata) is one of four species of extremely venomous blue-ringed octopuses belonging to the family Octopodidae. This particular species of blue-ringed octopus is known as one of the most toxic marine animals in the world.
The greater blue-ringed octopus, despite its vernacular name, is a small octopus whose size does not exceed 10 centimeters, arms included, for an average weight of 80 grams. Its common name comes from the relatively large size of its blue rings (7 to 8 millimeters in diameter), which are larger than those of other members of the genus and help to distinguish this type of octopus. The head is slightly flattened dorsoventrally (front to back) and finished in a tip. Its eight arms are relatively short.
There are variable ring patterns on the mantle of Hapalochlaena lunulata with varied coloration in correlation to their ambient environment, from yellow ocher to light brown or even white-ish (when inactive). The blue rings, which number around 60, are spread throughout the entirety of its skin. The rings are roughly circular in shape and are based on a darker blotch than the background color of the skin. A black line, with thickness varying to increase contrast and visibility, borders the electric blue circles. The blue rings are an aposematic adornment to clearly show to all potential predators that the octopus is highly venomous. The octopus also has characteristic blue lines running through its eyes.
The octopus usually flashes its iridescent rings as a warning signal, each flash lasting around a third of a second. To test the theory if blue-ringed octopuses could produce their own blue iridescence, scientists bathed the octopus samples in a wide range of chemicals that were known to affect chromatophores and iridophores. It was found that none of the chemicals used affected the octopuses' ability to produce its blue rings. It was also found that after examining the blue rings (specifically the iridophores) were seen to shift to the UV end of the spectrum which is a defining characteristic of multi-layer reflectors. It was also found that the iridophores are nicely tucked into the modified skin folds, kind of like pouches, which could be contracted by the muscles that connect the center of each ring to the rim. When the muscles then relax, the muscles around the perimeter of the ring contract which in turn causes the pouch to open to expose the iridescent flash. The octopus can then expand the brown chromatophores on either side of its ring to enhance the contrast of its iridescence. After all of the testing was complete, it was determined that the muscle contracting mechanisms was key to how the blue-ringed octopus portrayed its iridescent signaling success.[2]
The greater blue-ringed octopus is a benthic animal that has a solitary way of life and is widespread throughout the tropical and subtropical waters of the Indo-West Pacific, from Sri Lanka to the Philippines and from Australia to Papua New Guinea, the Solomon Islands and Vanuatu. The animal prefers shallow waters with a mixed seabed (such as rubble, reefs and sandy areas). As is true for all octopuses, it lives in a burrow and only comes out to search for food or a mate. The entrance of the shelter is littered with remains from meals (empty shells and crab shell and legs) and is easily identifiable.[3]
The blue-ringed octopus diet typically consists of small crabs and shrimp. They also tend to take advantage of small injured fish if they can catch them. Its known hunting behavior consists of pouncing on its prey, seizing it with its arms, and then pulling it towards its mouth. It uses its horny beak to pierce through the tough crab or shrimp exoskeleton, releasing its venom. The venom paralyzes the muscles required for movement, which effectively kills the prey.
The initiation of physical contact is completely independent from sex, size, or residency status which left no notable changes of behavior based on sex alone. However, Spermatophores are only released during sexual interaction with females but not with males which indicates that upon copulation, the male can distinguish the difference on whether to inseminate or not. The copulation times between male-female are roughly 160.5 minutes, while the copulation times with the male-male interactions lasted about 30 seconds. Ultimately the studies that were conducted determined that until copulation occurs, prior to insertion of the hectocotylus, the male cannot determine the difference in sex.
The breeding season varies according to geographical area. The female lays between 60 and 100 eggs, which are kept under the female's arms during the incubation period, which lasts about a month. Newborns have a brief planktonic development passage before settling on the seabed.
The mating ritual begins when a male approaches a female and begins to caress her with his modified arm, the hectocotylus. Males then climb on the female's back, at times completely engulfing the female’s mantle obstructing her vision. The hectocotylus is inserted under the mantle of the female and spermatophores are released into the female’s oviduct. Males die after mating. The female then lays between 50 and 100 eggs and guards them by carrying them under her tentacle until they hatch about 50 days later into planktonic paralarvae. The female then dies as she refuses to eat while she guards her eggs. The blue-ringed octopus is about the size of a pea when hatched then grows to reach the size of a golf ball as an adult. They mature quickly and begin mating the following autumn. Their average lifespan is about 2 years.
The greater blue-ringed octopus is capable of inflicting a deadly bite to its predators that can potentially be fatal to humans. Octopuses from genus Hapalochlaena have two kinds of venom glands that impregnate their saliva. One is used to immobilize the hunted crustaceans before eating them. The second, tetrodotoxin, is used for defense and is found in several other sea creatures such as pufferfish. Tetrodotoxin, also known as TTX, is secreted from the posterior salivary glands which is connected to the beak. The greater blue-ringed octopus is known as one of the most venomous marine animals in the entire world. For humans, the minimal lethal dose of tetrodotoxin is estimated to be about 10,000 MU, which is about 2 mg in crystal form. TTX does not decompose during heating or boiling and there is no known antidote or antitoxin for this toxin. It is believed that the TTX serves as a hunting tool for paralyzing prey as well as a defense mechanism to other predators.[4] This toxin is a powerful neurotoxin and a strong paralytic. The bite is painless to humans but effects appear any time between 15 and 30 minutes and up to four hours, though the rate of onset of symptoms varies by individual, and children are more sensitive to the toxins.
The first phase of the poisoning is characterized by facial and extremity paresthesia, and the victim feels tingling and/or numbness on the face, tongue, lips, and other body extremities. The victim may also suffer excessive sweating, severe headaches coupled with dizziness, speech problems, hypersalivation, moderate emesis, movement disorders, a feeling of weakness, cyanosis to extremities and lips and petechial hemorrhages on the body.
The second phase of poisoning usually occurs after eight hours and includes hypotension and generalized spastic muscle paralysis. Death may occur between 20 minutes and 24 hours after the onset of symptoms, usually resulting from respiratory paralysis. Throughout each of the phases of poisoning, the state of consciousness of the victim is unaffected.[5]
Greater Blue Ringed Octopuses express VGSC (HlNav1) gene mutations that greatly reduce the channels TTX binding affinity which in turn render the octopus TTX resistant. TTX selectively binds and blocks the ion-conducting pore of the voltage-gated sodium channel which are responsible for the ability of an organism to move. The greater blue-ringed octopus naturally produced TTX and bears a phenotype in the genus for the resistance to TTX. It was found that the resistance was caused by a combination of amino acid substitutions in the TTX binding sites for the primary voltage-gated sodium ion channel.
The greater blue-ringed octopus (Hapalochlaena lunulata) is one of four species of extremely venomous blue-ringed octopuses belonging to the family Octopodidae. This particular species of blue-ringed octopus is known as one of the most toxic marine animals in the world.
El pulpo mayor de anillos azules (Hapalochlaena lunulata) es una de las cuatro especies de pulpos de anillos azules venenosas pertenecientes a la familia Octopodidae.
El pulpo mayor de anillos azules es, a pesar de su nombre vernáculo, un pulpo pequeño cuyo tamaño no exceda de 10 centímetros, con los brazos incluyen, por un peso medio de 80 gramos.[1] Su nombre común proviene del tamaño relativamente grande de su azul anillo (7 a 8 milímetros de diámetro), por lo que son de hecho más grande que los de los otros miembros del género y ayudan a distinguirlos.[2] La cabeza está ligeramente aplanada dorsoventral y terminó en una punta. Sus brazos son cortos de altura.
La coloración de este pulpo varía según las circunstancias y el medio ambiente a partir de ocre amarillo a marrón claro a través blanquecino (cuando está desactivada). Los anillos azules son aproximadamente 60, extendido por toda la capa de todo el animal.[3] Los anillos son más o menos circular y se basan en una mancha más oscuro que el color de fondo de la capa. Una línea de negro, cuyo espesor puede variar para aumentar el contraste y sea más visible, las fronteras de los círculos de color azul eléctrico.
Los anillos azules son un adorno aposemática cuyo propósito es mostrar claramente a todos los depredadores potenciales que este pulpo es muy venenoso. También tienen líneas azules característicos que se ejecutan a través de sus ojos.
La mayor hapalochlaena[4] está muy extendida en las aguas tropicales y subtropicales del Indo-Pacífico occidental de Sri Lanka a las Filipinas y Australia del Sur a Japón.[1]
La mayor hapalochlaena le gusta aguas poco profundas con fondo mixto (escombros, arrecifes, zonas de arena ...). Al igual que todos los pulpos, que vive en una madriguera y sólo sale en busca de comida o de un compañero. La entrada del refugio está lleno de las piernas de las comidas (cáscaras vacías y caparazón de cangrejo y las piernas) y es bastante fácil de identificar.
La mayor hapalochlaena es un animal bentónico que tiene una forma de vida solitaria. La época de reproducción varía según la zona geográfica, la hembra pone entre 60 y 100 huevos que se mantienen debajo de los brazos de la hembra durante el período de incubación, que dura alrededor de un mes.[1] Los recién nacidos tienen un breve paso el desarrollo de plancton antes de colocar en el fondo del mar.
Este pequeño pulpo es un carnívoro activo que se alimenta principalmente de crustáceos, conchas de bivalvos y peces pequeños de vez en cuando.
Incluso si la mayor hapalochlaena parece tranquilo y dócil, no deja de ser capaz de infligir una mordedura mortal para sus depredadores que pueden incluso ser mortal para los humanos. Los pulpos de género Hapalochlaena tienen dos tipos de glándulas de veneno, que impregnan su saliva. Uno se utiliza para inmovilizar los crustáceos cazados antes de comerlos. La segunda, como un objetivo de defensa que veneno de la toxina se nombra maculotoxin. Esta toxina es una potente neurotoxina que posee un fuerte poder paralizante. Sus efectos son similares a la tetrodotoxina. La picadura es indolora y los efectos aparecen en función de los individuos, los niños son más sensibles a ella, entre los 15 y 30 minutos o hasta cuatro horas.
La primera fase de la intoxicación se caracteriza por parestesia facial y de las extremidades, la víctima se siente hormigueo y / o entumecimiento en la cara, la lengua, los labios y otras extremidades del cuerpo. La víctima también puede tener más de sudoración, dolor de cabeza, mareos, problemas del habla, salivación excesiva, vómitos, náuseas, diarrea, dolor abdominal, trastornos del movimiento y una sensación de debilidad, cianosis en las extremidades y los labios, hemorragias petequiales en el cuerpo.[5]
La segunda fase de la intoxicación por lo general se produce después de ocho horas e incluye la hipotensión y la parálisis muscular generalizada como un tipo espástico, es decir, que los músculos se contraen en exceso y sin control voluntario. La muerte puede ocurrir entre 20 minutos y 24 horas después del inicio de los síntomas. La muerte es por lo general debido a la parálisis respiratoria. Sin embargo, a lo largo de las fases de la intoxicación el estado de conciencia de la víctima no se ve afectada.
Datos: Q1123809
Multimedia:
Especies: Hapalochlaena lunulata
El pulpo mayor de anillos azules (Hapalochlaena lunulata) es una de las cuatro especies de pulpos de anillos azules venenosas pertenecientes a la familia Octopodidae.
Grand poulpe à anneaux bleus, Grande pieuvre à cercles bleus
Hapalochlaena lunulata, communément nommé Grand poulpe à anneaux bleus ou Grande pieuvre à cercles bleus, est un céphalopode de la famille des Octopodidae.
Le grand poulpe à anneaux bleus est malgré son nom vernaculaire un petit poulpe dont la taille est maximale n'excède pas 10 centimètres[4] (ou 15-20 cm[5]) bras compris pour un poids moyen de 80 grammes [6]. Son nom commun provient de la taille de ses anneaux bleus (7 à 8 millimètres de diamètre)[6], ils sont en effet plus grands que ceux des autres membres du genre et permettent ainsi de les distinguer.
La tête est légèrement aplatie dorsoventralement et se termine en pointe. Ses huit bras sont courts. La coloration de ce poulpe varie selon les circonstances et l'environnement du jaune ocre au brun sable en passant par une teinte blanchâtre (lorsqu'il est inactif). Les anneaux bleus sont au nombre d'environ 60 répartis sur tout le manteau de l'animal[7]. Les anneaux sont plus ou moins circulaires et reposent sur une tache plus sombre que la couleur de fond du manteau. Un trait noir, dont l'épaisseur peut varier pour augmenter le contraste et être plus visible, cerne les cercles bleus électriques. Les anneaux bleus constituent une parure aposématique dont le but est de signaler clairement à tous les prédateurs potentiels que ce poulpe est venimeux.
Le grand poulpe à anneaux bleus est présent dans les eaux tropicales et subtropicales de la zone Indo-Ouest Pacifique du Sri Lanka aux Philippines et de l'Australie au sud du Japon[6].
Le grand poulpe à anneaux bleus apprécie les eaux peu profondes aux fonds mixtes (éboulis, récifs, zones sablonneuses...). Comme tous les poulpes, il vit dans un repère et ne sort que pour rechercher sa nourriture ou un partenaire afin de se reproduire. L'entrée de son abri est jonchée de débris de repas et donc assez facilement identifiable[8].
Le grand poulpe à anneaux bleus a un mode vie solitaire et benthique. Lors de la période de reproduction qui varie selon la zone géographique la femelle pond de 60 à 100 œufs qu'elle maintient sous elle durant la période d'incubation qui dure environ un mois [6]. Les nouveau-nés ont un bref passage de développement planctonique avant de s'installer sur le fond [6].
Ce petit poulpe est un carnivore actif qui se nourrit essentiellement de crustacés, de coquillages bivalves et plus rarement de petits poissons [6].
Même si le grand poulpe à anneaux bleus semble calme et docile, il n'en demeure néanmoins capable d'infliger une morsure mortelle à ses prédateurs et celle-ci peut même s'avérer fatale pour l'homme [9]. Les poulpes du genre Hapalochlaena possèdent deux glandes à venin dont s’imprègne la salive, l'une est utilisée pour immobiliser les crustacés chassés et s'en nourrir et la seconde comme un moyen de défense dont la toxine du venin est nommée maculotoxine. Cette toxine est une puissante neurotoxine dotée d'un fort pouvoir paralysant. Ses effets sont identiques à la tétrodotoxine. La morsure est indolore et les effets apparaissent selon les individus, les enfants sont plus sensibles, entre 15 et 30 minutes voire quatre heures[10].
La première phase de l'empoisonnement se caractérise par une paresthésie faciale et des extrémités, c'est-à-dire que la victime ressent des fourmillements et/ou engourdissements au niveau du visage, la langue, des lèvres et autres extrémités corporelles. La victime peut également avoir des sueurs, des maux de tête, des étourdissements, des problèmes d'élocution, une hypersalivation, avoir des vomissements, des nausées, la diarrhée, des douleurs abdominales, des troubles moteurs et une sensation de faiblesse, une cyanose des extrémités et des lèvres, hémorragies pétéchiales sur le corps[11].
La seconde phase de l'empoisonnement survient en général au bout de huit heures et comprend une hypotension et la généralisation de la paralysie musculaire qui est de type spastique, c'est-à-dire que les muscles se contractent de façon excessive sans contrôle volontaire. Le décès peut survenir entre 20 minutes et 24 heures après le début des symptômes. Le décès est souvent dû à une paralysie respiratoire. Toutefois, durant toutes les phases d’empoisonnement l'état de conscience de la victime n'est pas affecté[12].
Grand poulpe à anneaux bleus, Grande pieuvre à cercles bleus
Hapalochlaena lunulata, communément nommé Grand poulpe à anneaux bleus ou Grande pieuvre à cercles bleus, est un céphalopode de la famille des Octopodidae.
Il polpo dagli anelli blu settentrionale (Hapalochlaena lunulata Quoy e Gaimard, 1832), noto anche come polpo dagli anelli blu maggiore, è un mollusco cefalopode della famiglia Octopodidae, diffuso nelle barriere coralline dell'Indo-Pacifico.
Come gli altri membri del suo genere, noti in inglese come "blue-ringed octopus" (polpi dagli anelli blu), è una specie famosa per il suo veleno, una neurotossina mortale, considerata fatale anche per un uomo adulto e in salute.
H. lunulata è uno dei polpi più piccoli; i polpi dagli anelli blu sono infatti noti per le loro piccole dimensioni, che raramente superano quelle di una pallina da golf. Il corpo (mantello) di H. lunulata è lungo circa 5 cm e le braccia 7 cm, con un peso variabile da i 10 ai 100 grammi, sebbene la media sia di circa 55 grammi.
Questo piccolo polpo vive nelle acque tropicali dell'Oceano Pacifico occidentale, dall'Indonesia alla Grande barriera corallina australiana. Vive nelle barriere coralline, nelle baie e nelle lagune a pochi metri di profondità, ma è molto comune soprattutto nelle pozze coralline che si formano momentaneamente lungo la costa con la bassa marea.
I polpi dagli anelli blu fanno uso dei propri cromatofori per mimetizzarsi con l'ambiente circostante, ma se provocati cambiano rapidamente colore, divenendo giallo brillante e facendo risaltare gli anelli blu. Si tratta di un chiaro avvertimento aposematico.
Caccia crostacei e pesci di piccole dimensioni, principalmente piccoli granchi.
Il suo morso è altamente velenoso e potenzialmente mortale anche per l'uomo, sebbene l'indole di tale mollusco sia sostanzialmente pacifica e timida e difficilmente aggredisce se non infastidito.
Nelle ghiandole salivari del polpo dimorano specie batteriche simbionti le quali sono responsabili della produzione di una tossina altamente velenosa, la tetradotossina, una neurotossina che uccide provocando la paralisi progressiva della muscolatura volontaria. Il becco a pappagallo del polpo punge facilmente la pelle e il muscolo sottostante. Il morso è relativamente indolore, ma il veleno che inietta è 100 volte più tossico del cianuro[1] a causa della presenza della tetradotossina: reagisce rapidamente, colpisce e paralizza i muscoli della vittima, provocando la perdita immediata del gusto, della sensibilità e della vista. Se non si interviene si rischiano paralisi e arresto respiratorio. Un solo morso può uccidere un adulto in 90 minuti; non si conoscono antidoti, ma il massaggio cardiaco e la respirazione artificiale riescono a spostare le tossine nell'organismo e impediscono danni a lungo termine. In tutto il XX secolo si contano, però, solo tre vittime riconosciute.
Il polpo dagli anelli blu settentrionale (Hapalochlaena lunulata Quoy e Gaimard, 1832), noto anche come polpo dagli anelli blu maggiore, è un mollusco cefalopode della famiglia Octopodidae, diffuso nelle barriere coralline dell'Indo-Pacifico.
Come gli altri membri del suo genere, noti in inglese come "blue-ringed octopus" (polpi dagli anelli blu), è una specie famosa per il suo veleno, una neurotossina mortale, considerata fatale anche per un uomo adulto e in salute.
De grote blauwring-octopus (Hapalochlaena lunulata) is een van de drie (of misschien vier) soorten blauwgeringde octopussen.
Dit dier wordt amper 10 cm lang. Ze hebben een massa tussen de 10 en 100 gram hoewel de meeste exemplaren rond de 55 g zitten.
De soort voedt zich met kreeftachtigen, krabben, en vis die hij met een neurotoxine, namelijk tetrodotoxine (dat geproduceerd wordt door een bacterie in de speekselklier), injecteert waardoor de prooi verlamd raakt en hij ze kan opeten.
De soort komt voor in de Grote- en Indische Oceaan in wateren rondom Australië op koraalriffen.
De grote blauwring-octopus (Hapalochlaena lunulata) is een van de drie (of misschien vier) soorten blauwgeringde octopussen.
Hapalochlaena lunulata é uma das três espécies venenosas de polvos-de-anéis-azuis. Ao contrário das espécies meridionais a ela aparentadas (Hapalochlaena fasciata e Hapalochlaena maculosa), que só se encontram em águas australianas, a distribuição desta espécie de polvo estende-se para o Oceano Pacífico ocidental tropical. Podem pesar cerca de 10 a 100 gramas, dependendo da sua idade.[1]
Alimenta-se principalmente de crustáceos, como caranguejos e camarões, embora ocasionalmente se alimente de peixes. Recorrendo à técnica da emboscada, estes polvos ferem as presas com um seu bico. A presa fica paralisada devido à poderosa neurotoxina presente na saliva do polvo, sendo facilmente devorada a seguir.
A neurotoxina presente na saliva, a tetrodotoxina, é produzida por bactérias nas glândulas salivares. A tetrodotoxina bloqueia os canais de sódio, causando paralisia motora e paragem respiratória após alguns minutos de exposição, levando à paragem cardiorrespiratória devido à falta de oxigénio.[2][3] E segundo estudos, não há antídoto para essa toxina.
Hapalochlaena lunulata é uma das três espécies venenosas de polvos-de-anéis-azuis. Ao contrário das espécies meridionais a ela aparentadas (Hapalochlaena fasciata e Hapalochlaena maculosa), que só se encontram em águas australianas, a distribuição desta espécie de polvo estende-se para o Oceano Pacífico ocidental tropical. Podem pesar cerca de 10 a 100 gramas, dependendo da sua idade.
Büyük mavi halkalı ahtapot (Hapalochlaena lunulata), mavi halkalı ahtapot (Hapalochlaena) cinsinin 3 (belki de 4) türünden biri olup ölümcül zehirlidir.
Ağırlıkları çok farklı olabilir. 10 - 100 gr arasında değişebilmekle birlikte ortalama ağırlıkları 55 gr'dır.
Yalnızca Avustralya sularında görülen büyük mavi halkalı ahtapot, sık olmasa da Büyük Okyanus'un tropik kesimleriyle Hint Okyanusunda da görülebilmektedir.
Yengeç ve karides gibi kabuklularla beslenir. Ayrıca, mercan kayalıklarındaki balıkları da avlar. Avlarını nörotoksin etkiye sahip çok güçlü zehriyle felç ederek avlar.
Kuvvetli bir zehri vardır ve insanlar için ölümcüldür. Bu ahtapot tehlike anında mavi halkalarını bir araba farı gibi yanıp söndürerek karşısındakileri uyarır. Zehirlenme belirtileri genelde ilk gebeleme, karıncalanma, uyuşukluk, böbrek yetmezliği ve nefes almada zorluktur. En son ise kurban felç geçirerek ölür
İlkin ağızlılar ile ilgili bu madde bir taslaktır. Madde içeriğini geliştirerek Vikipedi'ye katkıda bulunabilirsiniz. Büyük mavi halkalı ahtapot (Hapalochlaena lunulata), mavi halkalı ahtapot (Hapalochlaena) cinsinin 3 (belki de 4) türünden biri olup ölümcül zehirlidir.
Bạch tuộc đốm xanh lớn, tên khoa học Hapalochlaena lunulata, là một trong 3 (hoặc có lẽ 4) loài của chi Hapalochlaena. Không giống như người anh em phía nam của nó, là bạch tuộc viền xanh và bạch tuộc đốm xanh phía nam chỉ được tìm thấy tại Úc, phạm vi của bạch tuộc đốm xanh lớn bao gồm một phần lớn vùng biển nhiệt đới Tây Thái Bình Dương. Bạch tuộc đốm xanh lớn có thể nặng từ 10 đến 100 gram tùy thuộc vào việc chúng là con non hay con trưởng thành.[1]
Bạch tuộc đốm xanh lớn ăn chủ yếu là động vật giáp xác như cua và tôm. Ngoài ra, nó ăn cá lạc tới quá gần. Nó bơm một chất độc thần kinh mạnh dễ dàng làm tê liệt con mồi, cho phép bạch tuộc có thể nuốt con mồi của nó.
Nọc độc của chúng (một loại nước bọt có độc tính mạnh) trong đó bao gồm một chất độc thần kinh được gọi là tetrodotoxin, được sản xuất bởi vi khuẩn trong tuyến nước bọt. Chúng gây tê liệt cơ và ngừng thở trong vòng vài phút tiếp xúc, dẫn đến tim ngừng đập do thiếu oxy.[2][3]
Bạch tuộc đốm xanh lớn, tên khoa học Hapalochlaena lunulata, là một trong 3 (hoặc có lẽ 4) loài của chi Hapalochlaena. Không giống như người anh em phía nam của nó, là bạch tuộc viền xanh và bạch tuộc đốm xanh phía nam chỉ được tìm thấy tại Úc, phạm vi của bạch tuộc đốm xanh lớn bao gồm một phần lớn vùng biển nhiệt đới Tây Thái Bình Dương. Bạch tuộc đốm xanh lớn có thể nặng từ 10 đến 100 gram tùy thuộc vào việc chúng là con non hay con trưởng thành.
Hapalochlaena lunulata (Quoy et Gaimard, 1832)
Большой синекольчатый осьминог (лат. Hapalochlaena lunulata) является одним из четырех видов рода ядовитых синекольчатых осьминогов, принадлежащих к семейству Octopodidae.
Несмотря на название, большой синекольчатый осьминог — небольшое животное, максимальный размер которого не превышает 10 сантиметров (вместе с щупальцами), и средней массой 80 грамм. Название объясняется размером голубых колец (7-8 мм), которые являются самыми крупными в роду. Всего колец до 60 штук, распределенных по всей поверхности.
Наиболее распространен Hapalochlaena в тропических и субтропических водах Индо-Тихоокеанской области, от Шри-Ланки и Филиппин до Южной Австралии и юга Японии.
Живет преимущественно на мелководьях со смешанным рельефом (рифы, песчаные участки и т. д.). Как и многие осьминоги, обитает в норах, выходя в поисках пищи или партнера. Вход в нору довольно легко опознать, так как он часто окружен остатками добычи (пустые панцири крабов и раков).
Является донным животным, ведет одиночный образ жизни. Сезон размножения варьирует в зависимости от географического района, самка откладывает от 60 до 100 яиц, которые крепятся к телу самки на время инкубационного периода, который длится около месяца. Новорожденные имеют короткий этап развития в свободно плавающем состоянии, прежде чем остановиться на морском дне.
Этот маленький осьминог является активным хищником, питается в основном ракообразными, двустворчатыми моллюсками, редко — мелкой рыбой.
Хотя большинство синекольчатых осьминогов кажутся маленькими и безобидными, они способны нанести агрессору смертельный укус, способный убить даже человека. Эти осьминоги имеют два типа ядовитых желез.
Яд первого типа желёз используется осьминогами для парализации добычи, такой как ракообразные, во время охоты. Яд второго типа желёз — макулотоксин — используется для защиты. Это мощный нейротоксин, который сильным парализующим действием, напоминающим действие тетродотоксина. Укус безболезненный, и эффект проявляется субъективно. Дети более чувствительны к воздействию яда. Действие макулотоксина длится от 15-30 минут вплоть до четырех часов.
Первая фаза интоксикации характеризуется парестезией лица и конечностей, жертва чувствует покалывание и/или онемение лица, языка, губ, других частей тела. У пострадавшего начинается повышенное потоотделение, головная боль, головокружение, обильное слюноотделение, рвота, тошнота, диарея, боль в животе. Из-за воздействия макулотоксина пострадавший невнятно говорит, ощущает расстройство движений и слабость. Отмечается цианоз в конечностях и губах, точечные кровоизлияния на теле.
Вторая фаза интоксикации, как правило, происходит через восемь часов после укуса и включает в себя гипотонию и обобщенный паралич мышц (то есть, мышцы сокращаются чрезмерно, без добровольного контроля). Смерть может наступить от 20 минут до 24 часов после появления симптомов, как правило, из-за паралича дыхания. Тем не менее, ни одна стадия отравления не влияет на сознание потерпевшего.
Большой синекольчатый осьминог (лат. Hapalochlaena lunulata) является одним из четырех видов рода ядовитых синекольчатых осьминогов, принадлежащих к семейству Octopodidae.
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