Unlike Sea Cucumbers, the 'Temporary' Anus of the Amazing Comb Jelly Subverts Human Cognition
The ocean is the most mysterious realm on Earth, and so far there are many undiscovered marine species, as well as numerous incredible wonders waiting for humans to explore.
Beautiful jellyfish, the mouth is also a chrysanthemum
In the depths of the sea, there is a kind of beautiful creature, sea anemones, jellyfish, starfish, coral... seemingly ordinary, but they all have a quirky commonality, that is, they all have only one hole, if humans compare it, it is like food eaten inside the stomach turns into feces, then spit out from the mouth, that is, no anus and no mouth (called excretory pore).
Clownfish and sea anemones
Today I want to talk about a creature similar to jellyfish, its English name is Mnemiopsis leidyi, its Chinese name is translated as comb jelly, it is also often translated as temperate sea comb jelly. Comb jelly is a comb jelly with a length of 100mm, the body is elongated and flattened on both sides, and there are large flap leaves near the original mouth, forming four obvious deep grooves, which is a characteristic of this species, the color is usually transparent or slightly milky, semi-transparent
German biologist Ernst Haeckel's 'Form of Things Natural' in 1904, comb jelly
Recently, a new study found that the comb jelly previously considered to be similar to jellyfish, has been misunderstood by scientists for decades, it is not a jellyfish with no excretory pore, but an animal with an excretory pore! Unlike comb jelly, comb jelly does not have a mouth that is both anus and mouth. Instead, it passes its waste through the epidermis when necessary, forming a special temporary anus.
Comb jelly specimens at the Boston Aquarium
Comb jelly is considered one of the most primitive life forms on Earth today. Although they are like jellyfish and elegant and transparent, in fact they are entirely another kind of animal. This gel-like creature belongs to a group called shedder animals, and even eats jellyfish. Strangely, the anus of comb jelly will come and go according to the need.
Temporary anus of comb jelly
Indeed, comb jelly only has an anus when it needs to defecate, and in all other cases, the anus does not exist. This phenomenon is called 'temporary' anus because it is constantly changing, and sometimes comb jelly has more than one anus.
According to New Scientist, marine biologist Sydney Tam at Woods Hole Oceanographic Institution discovered this finding, he said he had not observed any animals with temporary anus before. Tam said: 'This is a very spectacular discovery.' 'As far as I know, there are no other animals with temporary anus, this subverts the previous cognition.'
Colorful sea urchins deep in the sea
Many animals, such as mammals and countless other animals, have what is called 'rectum', which is the beginning and end of the animal's digestive tract or a small hole from the mouth to the anus. But some jellyfish have a digestive tract with only one hole, which means they have to eat and excrete through the same hole. Scientists once thought that comb jelly belongs to this kind of animal. But the result of the study was surprising, comb jelly did not have a continuous connection between the intestine and the anus, it will excrete waste until the waste is too much to cause the intestine to merge with the epidermis and form a temporary opening, the waste can be ejected from the excretory pore. Once the comb jelly has successfully excreted all the waste, it will contract and re-form the form without anus.
Comb jelly excretion process diagram
Although this process seems troublesome, because its intestine and epidermis are only one cell thick, the entire process is quite easy to realize. Scientists' research also found that comb jelly often defecates. Adults are five centimeters long, and they excrete once every hour; larvae excrete once every ten minutes.
