#Class: Scyphozoa

[haveyouseenthisanimal-irl]

Range: Atlantic, Arctic, Pacific, & Indian Oceans

[donuts4evry1]

Speaking of the Vietnamese wiki pages- LOOK AT THIS!! LOOK AT THIS???

It’s a clusterfunk of a page.

It’s titled “Con sua” (the general word for jellyfish), but the page seems to talk specifically about Scyphozoa? But the orders (That’s what I think “Cac bo” is referring to) are... intelligible.

There are 3 extant orders in Scyphozoa as of late, that being orders Coronatae, Semaeostomeae, and Rhizostomeae. Order Rhizostomeae, despite being widely eaten and somewhat popular around East and Southeastern Asia, is absent from here. Two mysterious orders I haven’t even heard about are here as well, for some reason???

Anyways, searching them up on the English google didn’t get me anything exactly, but these seem to coincide with extinct fossil groups that have been speculated to be in class Scyphozoa at some point... (the wiki itself tells me this as well with some bits that I put through a translator lol)

[mbari-blog]

Jellies are trending 🙌🏼⁠

Everyone is familiar with the basic idea of a jellyfish, but what do we mean when we use that term? Jellies in the class Scyphozoa include most of the species that people think of when hearing the word “jellyfish.” Their life cycles typically include a polyp stage, attached to the bottom, that produces baby medusae. When conditions are right, these babies can grow up to form vast blooms of adult jellies. These "true jellies" are commonly studied at the sea surface, but those living deep in the water column are less well known. Some deep-sea jellies defy what we imagine when we think of jellyfish—some with bells that can stretch up to a meter across, others with no tentacles at all. ⁠ ⁠ Many species of swimming jellies are actually in another group called the Hydromedusae. These jellies are often small and transparent, ranging from very few to numerous tentacles. Some Hydromedusans have tentacles that point ahead of them instead of trailing behind them as they swim. These species eat other gelatinous organisms rather than the crustaceans favored by many of their cousins. Even with all this dazzling diversity, we have yet to encounter many of the delicate drifters that live in the deepest waters of our vast ocean. ⁠

[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)

[fishenjoyer1]

Fish of the Day

Today's fish of the day is the flower hat jelly!

The flower hat jelly, scientific name Olindias formosus, is a small and rare jelly known for the multicolored tentacles and luminescent display. Belonging to the hydrozoa family, the flower hat jelly is not actually a true jellyfish. The main difference between them being that true jellyfish belong to the Scyphozoa class, and have a life cycle defined by a longer period as a medusa (their adult form) whereas hydrozoans have a lifecycle primarily defined by their polyp or juvenile stages, sometimes even lacking medusa forms, a pattern that can once again be found in the flower hat jelly's life cycle. Their distribution is off the coastline of Japan, Korea, and countries within Oceania. Although some believe that these jelly's can also be found outside of Argentina, and Brazil, it is thought this may be a close relative, Olindias sambaquiensis. With a depth range from sea level down to 55m of depth, these jellyfish tend to live near the ocean floor where they can hide among kelps, sea grasses, and loose rocky bottoms.

Living a nocturnal life, the flower hat jelly spends its days hiding on the ocean floor. But, once dusk arrives this jelly rises from its hiding places to capture small fishes within its tentacles, paralyzing and or killing the fish, before drawing the corpse up into the bell to be consumed. The stings from this jelly are painful, and at least one fatality has been recorded from them in Japan.  These tentacles hold most of the intrigue of the flower hat jelly.  The length of the tentacles may appear to be random, but has been found to be arranged mathematically in an optimization hashing algorithm known as fibonacci hashing. Length aside however, these jelly's, and especially their tentacles contain fluorescent proteins, which are used to attract prey when hunting, and are particularly bright under blacklight. This protein is uniquely interesting due to its use in helping treat some COVID cases, as it can be used as an inhibitor, stopping the replication of the disease, and slowing or halting its spread.

The reproduction and younger stages of the flower hat jellyfish were a mystery for many years, but in 2012 the Monterey Bay Aquarium managed to be the first to breed them in captivity, capturing a full lifecycle from larvae to polyp to medusa. Beginning as polyps attached to a hard surface along the seabed, where they are completely stationary, surviving off of a single active tentacle, which is waved back and forth to gather nutrients, forming a medusae and releasing them only once a size of 1mm was achieved. Then they will mature into juvenile medusa, which are identical to adult medusa in appearance and behavior, only being identifiable by their smaller size and less tentacles. Juvenile medusa only being around 2-20mm, and adults getting only as large as 6inches total throughout their lifespan. Adult flower hat jellies are only observed in the months of December-July with peaks in the months of May and April. However, we understand very little about how these jelly's sexually breed in the wild, but fertilization occurs externally, as gametes are released into the water to create small, non-cooperative colonies along similar areas. These animals live only 4-6 months as adults, and only around a year total before slowly losing their fluorescence and passing away.

That's the flower hat jelly, everybody, have a wonderful Tuesday!

[respect-the-locals]

🪼Daily Cnidarian Fact:🪼

Flower Hat Jellyfish: Flower hat jellies are nocturnal and remain on or close to the sea bottom during the day. They are found off of southern Japan, Argentina, and Brazil. Although they look like a jellyfish, they actually belong in the class Hydrozoa, while true jellyfish belong in class Scyphozoa. The adult form of the flower hat jelly only lives a few months and is typically seen from December to July, with peaks in April and May.

[taxonomytournament]

Taxonomy Tournament: Cnidarians

Scyphozoa. This class is known as the true jellyfish, with a planktonic medusa form and bottom-dwelling polyp form

Hydrozoa. This class is of predatory cnidarians, some of which are colonial, incllude hydras and the Portuguese Man o' War

[kaviicoffee]

I loooove jellyfish so much, especially my favorite: the Phantom Jellyfish ( sygiomedusa gigantea )

Kingdom: Animalia Order: Semaeostomeae

Phylum: Cnidaria Family: Ulmaridae

Class: Scyphozoa

fun facts because I wanna info dump :3

The diameter of the bell can grow up to be 1 meter and their arms¹ can grow up to a length of 10 meters.

They have no stinging tentacles!

The s. gigantea is the only species of deep sea jellyfish that is monotypic².

Only around 110 sightings of them have been seen for the past 110 years despite being believed to live widespread around the world.

¹ Instead of stinging tentacles like usual jellyfish, the s. gigantea have arms to capture and trap prey. ( Plankton, small fish. )

² Monotypic in this context means that the species ( in this case, s. gigantea ) does not have any subspecies.

Let me know if I got anything wrong! Or add on anything if you'd like. If you hyperfixate on jellyfish, please tell me about your favorites!

ヾ(≧▽≦*)o

[v4ll3y]

Flower Hat Jelly Gender

USE WITH CREDITS PLEASE!

Flower hat jelly gender - when one may act or appear as one gender but is another. just like the jelly, they are to be more associated with being odd and embracing unattractive qualities of oneself.

I made this gender specifically because I wanted this gender centered around neurodivergence and how we may be perceived and stereotyped by others in society, especially when we may have a differing view on self expression. and so, this is a label for anyone, both binary and nonbinary identities can be added with this. while this was intended for neurodivergent people, neurotypical people can also use this identity as they see fit :)

Why a Flower Hat Jellyfish?

The flower hat jellyfish is not an actual jellyfish, which is where I got my inspiration to make this gender! While they look like jellyfish, they actually belong in the class Hydrozoa, and true jellyfish belong in class Scyphozoa. They are also often seen as "ugly" or "weird" by many while a few find beauty in them (thats me!!!). So, I purposely got colors directly from a flower hat jelly itself.

[inklovesjellyfish]

Sorry for not posting in a while, I feel pretty shitty, anyways, this is a Flower Hat Jellyfish. Though they are called "jellyfish" they aren't considered true jellyfish because unlike true jellyfish, who's class is Scyphozoa, their class is Hydrozoa. There stings are very painful and has only killed one man off the coast of Japan.

[haveyouseenthisanimal-irl]

Range: North, Black, Baltic, & Caspian Seas, Northeast Atlantic, & Northwest Pacific

[donuts4evry1]

tfw the wikipedia for the atolla jellyfish lists the "Crown jellyfish" (no species name) as a close relative of the Atolla jellyfish...

[mbari-blog]

Basking in the breathtaking beauty of our inner space 🌟⁠

This crimson jellyfish, Paraphyllina sp., uses the color red to camouflage itself in the deep sea. Because wavelengths of light in the red end of the spectrum are preferentially absorbed by seawater, red animals disappear into the darkness of the deep ocean. This enables them to ambush unsuspecting prey or avoid a hungry predator. The red pigment may also help to mask any bioluminescent prey that it has eaten.⁠⠀⁠ ⁠⠀⁠ Jellies in the class Scyphozoa include most of the species that people think of when hearing the word “jellyfish.” These "true jellies" are commonly studied at the sea surface, but those living deep in the water column are less well known. We are still just learning what species thrive in the dark depths of our ocean and how they live and reproduce. Exploration with ROVs allows us to see these enigmatic animals in their habitat and gives us a better understanding of their ecology.

[jellyfishobsessor]

Difference in Cnidaria Classes

There are 4 different types of phylum cnidaria classes. These classes being Hydrozoa, Scyphozoa, Cubozoa, and Staurozoa. Let's start!

Note: I would also like to add that siphonophores are NOT jellyfish. Although they may share a class in phylum cnidaria, they have many differences. However, I will address that in another post.

Hydrozoa

Hydrozoans are small jellyfish who only spend part of their lifetime as jellyfish. Their lifespan can range from up to a few minutes, to a few months. An exception of this fact is the immortal jellyfish. Some hydrozoans are actually colonial as well.

Some examples of this class are freshwater jellies, as well as siphonophores.

Scyphozoa

Scyphozoans are the most abundant kind of jellyfish. These jellies are typically bigger than most. Even as a polyp, they are far more developed than the rest. This is actually what differentiates Scyphozoans from Hydrozoans, as they're often mixed up.

Hydrozoans spend part of their lifetime as polyps, where the medusa is small and sometimes even absent. As I stated before, Scyphozoans are much more developed at an earlier stage than most jellies.

Cubozoa

Cubozoans are one of the easiest to identify from looks. As is suggests in the name, it's box shaped. When looking at it from above, or even from the side, they have a very cube like structure; Along with evenly spaces out tentacles in each corner.

What makes these jellies unique is the fact that they actually have developed eyes! But although having developed eyes, their sight isn't really their strong suit. However, their sight is well enough to spot predators earlier than the regular jellyfish can.

Staurozoa

Staurozoa are VERY different than the average jellyfish. They are not free floating, nor do they look like one either. These jellies are actually stalked, and attach themselves to surfaces.

They possess 8 oral arms, in which they use to catch food. Because of their looks, they are often mistaken for sea anemones.

What also makes them unique is the fact they have no life cycle changes. They remain in one spot for their entire life. From their polyp stage, to their medusa stage, they will stay attached to one surface until they reach the end of their life span; Or until they are eaten.

[the-jellydex]

"You can't be a true jellyfish without being in class Scyphozoa" my ass if ur a jellyfish you're a jellyfish 🤦🤦

Jellyfish elitism? In my informational jellyfish video? Better check your bias or your days are numbered (/j)

[puppetboysx3]

Drymonema Larsoni

Drymonema larsoni (sometimes nicknamed "pink meanie") is a species of jellyfish belonging to the Scyphozoa class These fellas eat other jellyfish with a preference for moon jellyfishs, when they are little they tend to eat zooplanktons, but as they grow they turn to a jellyfish diet

They can grow to be 70 feet long and have been seen to weigh up to 50 pounds

they arent usually seen as a threat to humans but they can leave a painful sting

I think their pretty:3

-M