#box jellyfish

[critter-creature-or-beast]

These are...

critters

creatures

beasts

Voting ended onMay 4

By Peter Southwood, CC-BY-NC

[witheringinthehospital]

I love how jellyfish are more, ig "popular" now but i do kinda hate how "aesthetic" theyve become now

Because its like yes theyre gorgeous creatures and yes they do fit ur pinterest, blue, coquette aesthetic

BUT

These are literally some of the most dangerous creatures, how would u react seeing this beast while swimming?

Or would u still find it aesthetic after coming into contact with a box jellyfish? The most dangerous creature ?

I dont mean to rain on everyones parade obviously ur allowed to like what u like and u dont need to know everything or take everything into consideration. But i do just kinda hate how its become like an aesthetic symbol if that makes sense

Im sick of seeing "amy ★🪼🫧🌀" type names cuz its like ik im taking it too literal, but do u like the creature or the look of it

ALSO TO PREPHICE NO HATE TO PEOPLE WHO DO THIS !!! ITS FINE TO JUST FIND THEM PRETTY OFC THAT WAS ME LIKE A WEEK AGO 😭😭 but idk i find the same thing with people who have bugs or spiders in their names just to be scared of them like, huh?

[fishstarrz]

look but don’t touch!!

[bethanythebogwitch]

Wet Beast Wednesday: box jellyfish

Jellyfish are curious things, but some are curiouser than others. Most jellyfish are members of the class Scyphozoa, which is a very diverse clade with plenty of jellies to choose from. But then there are the Cubozoa, a separate class of jellyfish that have a lot of interesting and unique features, such as being some of the most venomous animals in the world. Try not to get stung.

(Image: a box jellyfish. It is a mostly translucent jellyfish with a box-shaped bell. From the corners of the bell hand four tentacles that are a striped white and orange. End ID)

Like the Scyphozoa, the approximately 50 known species of box jellyfish have a body plan consisting of a bell and trailing tentacles. While the Scyphozoa have round bells, box jellyfish have cuboid bells, which give them their name. At each lower corner of the bell is a stalk that leads into one or more tentacles. The interior of the bell is divided into four regions by structures called septa. In each region is a gastric pocket that helps direct food into the central stomach and has structures that help water flow into and out of the animal. Each septa is lined with digestive filaments and two of the jellyfish's eight gonads. In the center of the bell is a flexible, trunk-like appendage called the manubrium which contains the mouth and stomach. When thebox jellyfish eats, it draws prey into the one of the septa where the digestive filaments begin digestion. The manubrium then maneuvers the mouth over to the prey and eats it. Prey is captured with the tentacles, which are lined with stinging cells called cnidocytes which contain structures called nematocysts that inject venom into prey and threats. The tentacles then help move the food into the bell. While Scyphozoa come in a variety of colors, box jellyfish are almost always translucent.

(Image: a box jellyfish, this one having a squatter bell and multiple tentacles at each corner. The manubrium is visible through the bell as a curving, trunk-like structure. End ID)

Box jellyfish have a developed nervous system consisting of two portions: the nerve ring and the rhopalia. The ring nerve stretches around the base of the bell and controls how it moves. The rhopalia is a system of nerves that controls sensory structures. In particular, it controls a sense of gravity and the eyes. While some Scyphozoa have simple light-sensing eyes, the box jellyfish have true eyes with retinas, corneas, and lenses. Like the bell, the rhopalium is divided int four segments. Each segment has two true eyes as well as two simple pit eyes for detecting light levels and two simple slit eyes that likely detect movement. The true eyes can be oriented in different directions and they always appear to keep one pair pointing up. Thanks to their good eyesight and the shape of the bell allowing for rapid bursts of speed, the box jellyfish can actively hunt its prey instead of just drifting and waiting for food to come to them. What's more impressive is their ability to actively navigate their environment and learn to avoid certain threats. It was long thought that animals without brains would not be able to truly learn, but multiple types of cnidarians have shown learning behavior, with the box jellyfish seeming to be the most advanced.

(Image: a scientific diagram showing pictures of a box jellyfish eye and a drawing of its anatomy. End ID. Source)

Box jellyfish reproduce every year and are semelparous, meaning they only mate once before dying. However, there is some inconclusive evidence that the species Chiropsalmus quadrumanus may be able to mate multiple times. Reproduction can be both internal and external depending on species. In external reproduction, the male and female release gametes into the water. In internal reproduction, the pair will maneuver themselves so the openings of their bells face each other and the male will pass a packet of sperm to the female. In these species, the female retains the eggs internally until they hatch. The juveniles hatch as a type of swimming larva called a planua. The planua will eventually settle and become fixed to a hard surface, metamorphosing into a polyp. The polyp is a non-swimming stage found in all members of the clade Medusuzoa, of which the box jellyfish are a member. Polyps will grow for months to years and during this period, they can reproduce asexually by budding off clones of themselves. Eventually, the polyps will metamorphose into the adult medusa stage

(Image: photos of a box jellyfish at different stages of its life cycle. It starts as a bean-shaped planula, progresses to a worm-like creeping polyp, then to an anemone-like sedentary polyp, then to a newly released medusa, which looks like a tentacle-less box jellyfish. The medusa them matures to a small juvenile and finally a mature adult. end ID)

Box jellyfish are found worldwide in tropical waters, though most known species are from the Indo-Pacific. It is likely that many species ave been overlooked as their transparency and frequently small size makes it easy to miss them. New studies using e-DNA, DNA that is shed and collected through the environment, may help identify nee species and populations. Box jellyfish are known to most people as being some of the most venomous animals in the world, but only a few species are dangerous to humans. The species Chironex fleckeri is the most dangerous to humans. Its venom causes extreme pain and can lead to death within 2-5 minutes if enough venom enters the system. C. fleckeri has caused over 60 recorded deaths in Australia (because where else would it live?) and while there is now an antidote to the venom, getting it to the victim fast enough can be challenging. A singe C. fleckeri is often said to carry enough venom to kill 60 people. Most reported cases of stings have not ended in death as not enough venom was introduced to the system. Also from Australia (of course) are the Irukandji, a group of about 16 similar box jellyfish that can also be lethal, but while C. fleckeri at least has the decency to be big, the Irukandji jellyfish are all tiny. Their venom causes a reaction called Irukandji syndrome that is delayed for up to 2 hours after the sting and can lead to cardiac arrest if not treated. Jellyfish nets are common sights on Australian beaches. They enclose parts of the water with nets that have mesh small enough to keep most jellyfish out. Application of vinegar to the sting is the current recommended treatment and many beaches in Australia are required to stock it, though some research has indicated that vinegar may actually make the sting worse.

(Gif: footage of the rare spotted box jellyfish. It has a large bell with stripes and rings on it and the tentacles are thick and reddish. It is swimming, showing off the movement of the bell in how it propels itself. End ID)

[randomanimaloftheday]

Day 326#: Four-Handed Box Jellyfish

Today’s animal of the day is the Four-Handed Box Jellyfish (Chiropsalmus quadrumanus)!

Photo credit: Álvaro Esteves Migotto

This species of jellyfish can be found in the warm coastal waters of the western Atlantic Ocean along the eastern coast of North America, as well as in parts of the Pacific, such as around the coasts of Australia and Hawaii. Like other types of box jellyfish, they have a box-shaped bell that is mostly translucent, making them difficult to spot underwater. At each of the four lower corners of their bells, these jellies possess a hand-like appendage. Each of these “hands” has somewhere between seven and nine finger-like structures that end in a long stinging tentacle. These tentacles can be up to 13 ft long, which is crazy since their bells are only around 5 inches in diameter.

Photo credit: Cristina Cedeño-Posso

Like most species of jellyfish, the four-handed box jellyfish’s tentacles are covered in special stinging cells, called nematocysts, which they use to capture their prey and deter predators. Their diet mostly consists of whatever tiny fish or crustaceans happen to get too close to their tentacles, and once their prey has become paralyzed they transport it up into their bells, through their mouths, and then into one of their four stomach pouches. While these jellies don’t go out of their way to sting people, especially since they don't have brains and just kinda go where the current takes them, their stings are still incredibly dangerous to anyone who accidentally brushes up against their tentacles.

Photo credit: Heatherloveswildlife on iNaturalist

Even if you touch a dead one that's washed up on a beach it can still sting you, but since they're mostly clear, a lot of people end up touching one without even realizing until they get stung. Symptoms of four-handed box jellyfish stings include extreme pain, a rash appearing in the stung area (which can last for months), cardiac dysfunction, and respiratory issues. While there is an anti-venom, it needs to be administered as soon as possible in order to work. Children are especially at risk due to their stings, and there have been cases of very young children dying just 40 minutes after being stung! You're most likely to encounter these jellyfish right after heavy storms, since the waves wash them ashore and they end up getting beached. They also seem to migrate closer to shore during times of extreme droughts, since the lack of rain increases the salinity levels of the ocean.

[psappho-loves-staurozoans]

Drew a species of Cnidarian for every class 1. *Chrysaora colorata* 2. *Melithæa ochracea* 3. *Tripedalia cystophora* 4. *Hydra vulgaris* 5. *Aulactinia veratra* 6. *Myxobolus cerebralis* 7. *Polypodium hydriforme* 8. *Calvadosia campanulata*

[joblessmonday999]

some of my fav jellyfish species!!

SOMEONE PLEASE TALK TO ME ABOUT JELLYFISH

[marinebioblr]

At first glance, some may mistake this as the infamous box jellyfish. But actually- this is its cousin, the ✨️box jellyfish✨️! Confused?

Jellies are a prime example of why common names are often misleading or cause confusion. In actuality, "box jellyfish" has been given to dozens of species of jellies that belong to the class Cubozoa. The most infamous are the irukandji and Chironex fleckeri, which often pop up in the news as simply "box jellyfish" or "sea wasps."

The specimen in this video, while possessing a sting you would certainly want to avoid, is not of the lethal sort. While difficult to identify conclusively, it is likely Alatina alata or a close relative. Also known as the sea wasp or box jelly - like so many other jellies are.

While it's not realistic to try and memorize every jelly species by scientific name to sort the deadly from the not-so-deadly, it's good to keep in mind that not all box jellies are the vilified species. But I still wouldn't recommend putting any of their stings to the test!