Archive for Sand jellyfish
The oldest known fossils of jellyfish have been found in rocks in Utah that are more than 500 million years old, a new study reports. The fossils are an unusual discovery because soft-bodied creatures, such as jellyfish, rarely survive in the fossil record, unlike animals with hard shells or bones.
“The fossil record is biased against soft-bodied life forms such as jellyfish, because they leave little behind when they die,” said study member Bruce Lieberman of the University of Kansas.
These jellyfish left their lasting imprint because they were deposited in fine sediment, rather than coarse sand. The film that the jellyfish left behind shows a clear picture, or “fossil snapshot,” of the animals.
“You can see a distinct bell-shape, tentacles, muscle scars and possibly even the gonads,” said study team member Paulyn Cartwright, also of KU.
The rich detail of the fossils allowed the team to compare the cnidarian (the phylum to which jellyfish, coral and sea anemones belong) fossils to modern jellyfish. The comparison confirmed that the fossils were, in fact, jellyfish and pushed the earliest known occurrence of definitive jellyfish back from 300 million to 505 million years ago.
The fossils also offer insights into the rapid species diversification that occurred during the Cambrian radiation, which began around 540 million years ago and when most animal groups start to show up in the fossil record, Lieberman said.
The complexity of these early jellyfish seems to suggest that either the complexity of modern jellyfish developed rapidly about 500 million years ago, or that jellyfish are even older and developed long before that time.
Image provided by the NY Times
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Tropical-dwelling box jellyfish have a cube-shaped body, and four different types of special purpose eyes: The most primitive set detects only light levels, but another is more sophisticated and can detect the color and size of objects. The Australian box jellyfish is also deadly; each of its up to 60 tentacles carries enough toxin to kill 60 people
A set of special eyes, similar to our own, keeps venomous box jellyfish from bumping into obstacles as they swim across the ocean floor, a new study finds.
Unlike normal jellyfish, which drift in the ocean current, box jellyfish are active swimmers that can rapidly make 180-degree turns and deftly dart between objects. Scientists suspect that box jellyfish are such agile because one set of their 24 eyes detects objects that get in their way.
“Behavior-wise, they’re very different from normal jellyfish,” said study leader Anders Garm of Lund University in Sweden.
Whereas we have one set of multi-purpose eyesthat sense color, size, shape and light intensity, box jellyfish have four different types of special-purpose eyes. The most primitive set detects only light levels, but one set of eyes is more sophisticated and can detect the color and size of objects.
One of these eyes is located on the top of the cup-like structure, the other on the bottom, which provides the jellyfish with “an extreme fish-eye view, so it’s watching almost the entire underwater world,” said Garm, who will present his research at the Society of Experimental Biology’s annual meeting in Scotland.
Credit: Anders Garm/Life Science
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The stealthy predator Mnemiopsis leidyi, also known as the sea walnut, uses tiny hairs, called cilia, to create a current which prey don’t notice until they are sucked into its mouth region, surrounded by two large oral lobes. The sea walnut swims using fused cilia, which diffract light in many colors in this photo.
Mnemiopsis leidyi, as it’s formally called, is a ctenophore, a group of simple animals often described as jellyfish that propel themselves using tiny hairs, called cilia.
These jellyfish are native to the Atlantic Coast of the Americas, but they can be successful, even devastating, when introduced elsewhere. In the 1980s they showed up in the Black Sea, most likely transported by ships, and multiplied. Within a few years, the Black Sea’s anchovy fishery collapsed. Mnemiopsis was one of the culprits, since it both competes with the filter-feeding fish for food and also consumes anchovy eggs and larvae.
Mnemiopsis has also established itself elsewhere, including the eastern Mediterranean, the Caspian Sea, the Adriatic Sea, the Baltic Sea, parts of the North Sea, and elsewhere, according to the scientists.
The thimble jellyfish is the half-inch long and is found in the north Atlantic, Arctic and northern Pacific coastal waters during spring and early summer. It has four tentacles, that are covered with the usual nematocysts that discharge the toxins. This jellyfish is known to feed on crustacean plankton and barnacle larvae. It swims intermittently and then holds still with its tentacles extended. A passing prey is captured when it comes in contact with its tentacles. The toxins in the tentacles will immobilize the small prey and they will bend inwards to take the prey to the mouth where it is ingested and digested.
The sting of the thimble jellyfish is not deadlybut will usually cause a burning and itching. The thimble jelly is also hard to detect, but actually it is the larvae of this jellyfish that causes the main problem to bathers in the Caribbean. These larvae are often refereed to as sea lice, and cause a lot of painful rash, called the “seabather’s eruption” on the victim. They are very tiny and you wont know that you have been affected until the rash appears. These tiny jellyfish usually will get caught in between the swim suit and the skin of the person. The parts that get rubbed will get the most infestations, like the inner thighs, armpits, neck and so on. StingMate provides very effective relief on the rash discomfort.
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Jellyfish have always been adept in springing surprises at humans. One such surprise was encountered by a Jellyfish expert Lisa Gershwin in Tasmania. Lisa is responsible for the Jellyfish department of the local Museum and art gallery. She was out swimming in Tasmania, near a local jetty, when she saw a Jellyfish with light being emitted from its body. This was her 159th discovery of Jellyfish.
Jellyfish do not have any kind of pigments in its body which emit light. But the neon Jellyfish are just a creation of light reflection. The cilia or hair like extensions on the body of these Jellyfish helps them in loco motion. When the light falls on these cilia and is reflected back, there is a beautiful rainbow formation with the Jellyfish looking like as if it is self illuminated.
But these neon Jellyfish are quite small, only 13 cms in length. The beauty of these creatures is quite short lived as they are very fragile and can shatter in to pieces on hitting a net. These neon Jellyfish are also called as Rainbow Jellyfish. They look as dazzling as a colorful Rainbow with their myriad of colors. It is a visual delight to see them at night or in dimly lighted waters. The rainbow colors glow so vibrantly in the background of the dark black waters at night.
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Cladonema radiatum is a small anthomedusa whose dome-shaped umbrella reached 6 mm in diameter. The whitish manubrium which bears the gonads can be seen through the translucent umbrella. On the margin of the umbrella, there are generally eight elongated bulbs from where branched tentacules stretch out. Under each one of these bulbs, 1 to 4 stalked buttons are used to stick on the substratum. The root-arm medusa often settles on seaweeds and Zostera. Belonging to planktonic species, it has a hopping way of swimming, then it suddenly folds its tentacles and let itself fall. Present from June to October, it can be very abundant during warm periods and can cause tingling sensation to bathers. This little medusa is the sexual swimming form of a small hydroid living fixed to seaweeds, marine plants and rocks.
It is found in the North-Atlantic Ocean, the North Sea, the English Channel and the Mediterranean Sea. It is also listed in Japan.
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The Blue Jellyfish is also known as Bluefire Jellyfish, scientific name Cyanea lamarckii. It is a jellyfish species of the Cyneidae family and is likely to be known as Cyanea capillata nozakii or Cyanea nozakii among populations in Western Pacific of Japan. Blue Jellyfish also sting and have their own unique effects. It’s important to realize that almost all jellyfish sting but the degree of the sting is contingent on the species in question and how your body reacts to a sting. As such, the typical effects and symptoms of a jellyfish sting can range from a simple rash to an angry blister that requires urgent medical attention.
Blue Jellyfish sting effects include intense hurtful pain, wheals, and rash while its progressive effects include vomiting, nausea, diarrhea, fever, sweating, chills, swelling of the lymph nodes, back and abdominal pain, among others. In case you are the type of person who reacts severely on stings, the blue jellyfish sting effects might make it difficult for you to breath. It can also lead into a coma and to some very extreme cases death if the venom spreads widely into your blood.
In case a blue jelly fish stings you, you don’t have to wait for the effects to show before treating it. First off, you should rinse the affected areas using sea water. You should by all means avoid fresh water as it will only exacerbate the pain. Don’t rub the affected area, neither should you apply ice on it, instead, let it to cool off on its own. Blue jellyfish sting effects might also leave you with tentacles on, which should be removed sparingly using tweezers. Never rub them off using your bare hands. Your aim should be to put out of action the extremity since any slight movement can make the poison spread.
Severe blue jellyfish sting effects would require you to seek further medical attention.
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