Octopus, squid, squid, etc., are actually mollusk phylum - cephalopods under the mollusks. What are the well-known animals under the mollusk phylum? All kinds of conch, freshwater snails and snails, all kinds of clams, oysters, clams and scallops, and then all kinds of octopus, squid, squid, cephalopods, today let's talk about how to distinguish octopus, squid, cuttlefish and squid?
Octopus, squid, squid, etc., are all mollusks under the phylum Cephalopods. What is a mollusk? Of course, the soft body of the light tone is easy to push down... Well, it's actually an animal with a soft body and a real body cavity.
What are the well-known animals under the mollusk phylum? There are gastropods – all kinds of conchs, freshwater snails and snails, bivalves – all kinds of clams, oysters, clams and scallops, and then there are the cephalopods we are going to talk about today – all kinds of octopuses, squid, squid, cephalopods, as the name suggests, the meaning of the foot on the head.
You're going to be surprised: scared? Octopus squid and conch clams are actually related! Nani!
Don't be surprised, this is really the case, I don't believe you buy a squid to go home and see if there is a piece of squid bone in its body? That's actually a degraded shell. This feature is even more pronounced in the nautilus, a living fossil of cephalopods, which still retains a spiral-like conch-like shell.
You're surprised again: scared? Is the Nautilus not a snail? Don't worry, and listen to me slowly.
To talk about the story of this cephalopod, that year is a long time ago, it was about 500 million years ago (fuck, after 500 million years of struggle, it was still used as an ingredient, so I can't bear it)... About 500 million years ago, from the early organisms evolved the nautilus with shells, and from the nautilus evolved the ammonite with shells and the arrow stones (which looked like squid).
At that time, cephalopods flourished, divided into 6 subclasses, namely Orthoceratoidea, Endoceratoidea, Actinoceratoidea, Nautiloiea, Ammonoidea and Coleoidea, of which the Nautiloidea alone has more than 900 genera and thousands of species. There are more than 10,000 species in the whole cephalopod! And almost all occupy the top of the food chain, and are the deserved kings.
Unfortunately, the collapse of marine ecosystems caused by the Permian-Triassic mass extinction more than 200 million years ago directly exterminated 97% of cephalopods until the Cretaceous mass extinction 65 million years ago, and the ammonite completely perished. Since then, except for the nautilus suborder and the subclass Of the Cockroach, the other 4 subclasses have been directly extinguished, and only a few 700 species of cephalopods can be seen today.
Ammonite fossils
Cephalopods survived the nautilus suborders and suborders, and the only order (1) Nautilus remains under the nautilus subclass. The suborder Plesiosaurs can be divided into decalopods and eight-brachiosauridae according to the number of feet. The general purpose of the ten wrists is characterized by 10 feet, the suction cups on the feet with handles, and a degenerated shell in the body. Including (2) the squid order, (3) microfin squid, (4) squid, (5) deep-sea squid and (6) gun order, the eight-wrist total order is 8 feet, the suction cup has no handle, and the inner shell has basically disappeared, including (7) octopus and (8) ghost slugs. That is to say, there are still 8 orders left in the existing cephalopods.
Then, I will briefly introduce the existing cephalopods and their representative species in order.
Nautilus
Quick identification: There is an outer shell similar to a conch
Common way to eat: Uncle Policeman, this is the person who wants to eat the first-class protected animal Nautilus!
The Nautilus is the ancestor of cephalopods, and is the only surviving cephalopod that still retains its shell, and there are still 2 genera and 6 species. The shell of the nautilus and the shell of the conch are fundamentally different, the shell of the conch is empty in the middle, and the shell of the nautilus is composed of many semi-closed small cavities, each small cavity is called a "chamber", each chamber has a small hole connected to each other, the "chamber" is filled with gas, and the Nautilus relies on the gas in the "chamber" to control its buoyancy.
Cut nautilus shell. The "room" can be clearly seen, and the largest of them is the place where the body of the Nautilus is held, called the "living room". As the body grows, the nautilus secretes a corresponding substance to form a new partition, and the adult nautilus can reach up to thirty "chambers". The shell of the Nautilus follows the golden section.
Like other cephalopods, the Nautilus preys on brachiopods. Its brachiopods do not have suction cups, but this does not affect its predation, because its brachiopods are too many, there are more than 90 of them! It is not so easy for the prey entangled by it to break free. The Nautilus has a good tooth mouth, with 9 teeth, which allows it to safely prey on small shrimp and even crabs.
Please ignore the artificially polished Nautilus shell... I just think this girl is very good-looking...
It should be noted that the Nautilus is listed as a First Class Protected Animal in China, and although small vendors in some coastal cities will sell Nautilus shells, it is illegal to buy and sell Nautilus shells in China. Girls who want to take pictures like this still have to think twice.
Spiral-shelled squid
Quick identification: there is an inner shell of spirulina in the body, a light emitter at the top of the body, only the top has 2 small fins, and there are 8 shorts and 2 longs for a total of 10 feet
Common Ways to Eat: This jun is a little far from your table...
The spin-shell squid is a very mysterious cephalopod creature, and its body has a squid bone similar to the nautilus shell, which is also composed of many "air chambers", except for the lack of "living rooms". Naturally, it also does not need a "living room", because this degraded shell is completely wrapped in its body, and in its body it only functions as a maw.
The spin-shelled squid has the basic characteristics of the general order of ten wrists: there are ten brachiopods, of which 8 are relatively short and 2 are very long for predation. The squid lives in deep waters of nearly a kilometer all year round, and in order to prey, it has evolved a special ability: luminescence. At the top of its brain hilars there is a fluorescent emitter that can attract prey over the net.
Another feature of the spin-shell squid is that when it encounters danger, it will hide its eyes and brachiopods in its head and make a "shrunken-headed squid".
The squid bone of the spin-shell squid is very similar to the nautilus shell, and there are also many "gas chambers"
A diagram of the structure of the squid in the spiral shell, where the squid bone similar to the shell of the Nautilus can be seen
Microfin squid (grapefish)
Quick identification: The body size is very small, generally around 1cm, with a small fin on each side, with 8 short and 2 long and 10 feet
Common way to eat: stir-fry with leeks and eggs
Microfin squid is the smallest cephalopod organism, the existing 8 species of microfin squid, the smallest is only 6 mm, the largest general body length is not more than 2 cm, they are round and fat very similar to grape grains, in some coastal cities can occasionally buy grape fish is actually the above picture of this mysterious microfin squid.
In addition to predation, some brachiopods of cephalopods also have to play a "more important" role. For example, the mysterious microfin squid, its male fourth pair of brachiopods is also called "stem foot", what does it mean? "Stem" well... You know... Because they do not have specialized external reproductive organs, the brachiopod pair takes on this heavy responsibility... Do you feel like you won't be able to look directly at the squid claws in the future?
Squid (Squid)
Quick recognition: the body is short and thick, the feet are relatively short, there is a white calcareous inner shell in the body (some ear squids do not), there are relatively large fins on both sides of the body, there are 8 short and 2 long and a total of 10 feet
Common ways to eat: white seared, grilled, stewed tofu, grilled dried cuttlefish
The squid and the cuttlefish and cuttlefish that we say every day are actually the same thing, and "wu" and "ink" reflect the characteristics of the inkjet cover when it escapes the attack: there is an ink sac in the body of the squid, and when it encounters an emergency, the squid will spew out a large amount of ink, muddy the sea, and escape by itself. As for the word "thief", it is really unjust, in fact, the ancients originally called it "squid", and when it was passed around, it became a "squid".
In fact, such a scene is not common in the life of the squid, and most of the time, it plays the role of a hunter. There is a layer of pigment cells in its skin, which has a lot of pigment cells, which can be expanded or contracted by nerve signals, and the skin color will change accordingly, and the squid uses this property to hide itself in the environmental background, and once there is a careless prey passing by, the squid will strike at a very fast speed, clinging to the prey with its brachiopods.
Trying to adjust the body color, trying to blend with the coral reef color of the squid
The biggest difference between the squid and several other cephalopods is that there is a calcareous inner shell in the body, which is what we call squid bone and sea mantis, which is degenerated from the original external shell and plays a role in supporting the body structure in the squid. The vast majority of squid retain this trait, but some small eared squid have gone a step further and completely degraded the inner shell. In addition, the squid is shorter and fatter than other cephalopods, with 10 brachiopods (8 brachiopods + 2 brachiopods), which can also distinguish it from squid and octopus.
The inner shell of the squid - the sea mantis
Not all squid creatures have inner shells: the very small-eared squid's sea mantis has degenerated and is barely visible
Deep Sea Squid
Quick identification: small in size with a light emitter on the body
There are a total of 6 species of deep-sea squid, which basically live in the middle or bottom waters of the ocean. In order to live in such a dark environment, the deep-sea squid has evolved a light emitter to attract those phototropic plankton to move closer to it.
The order Deep Sea Squid is divided into two families, one is the Deep Sea Squid Family, which is the one pictured above, which looks more like a spiral shell squid, with two small fins at the top of the body. Another family is the ctenophore squid family, which is characterized by its comb-like teeth on its fins. Of course, no matter which family, deep-sea squid is too rare for us ordinary people.
Heliopods (Squid)
Quick identification: Slender like the tip of the red tassel gun, with large fins, a thin transparent inner shell in the body, 8 short, 2 long and 10 feet
Common ways to eat: teppanyaki, grilled, fried squid rings, fried squid, squid shreds
The gun-shaped order is actually what we often call squid, also known as gun squid. "Gun" is to describe its body shape as slender as the tip of the red gun, and the slender shape is indeed an intuitive feature that distinguishes squid and squid. A more significant difference is in the body: unlike the squid, the inner shell of the squid is further degraded, leaving only a transparent flake of cuticle, and even the function of supporting the body is gone, but only as an attachment to the muscles.
There are many kinds of members of the order Gun, and the various forms are also very different. Under the order Gunshotera, it is divided into open-eye suborders and closed-eye suborders according to whether there is a membrane on the outside of the eyeball. The most famous representative of this branch is the famous king squid (king squid), which can grow up to 20 meters long and weigh about a ton, and is the largest cephalopod known to mankind. This kind of squid only lives in deep water, sperm whale in order to hunt this it, do not hesitate to carry out extremely deep diving, in the face of the sperm whale such a giant hunter attack, the king squid does not tie hands, but will use the multi-hook brachiopod counterattack, in many elderly sperm whale skin will find a scar, that is, the whale and the king squid in the process of fighting.
The closed-eye suborder is more familiar to us, and most of the various squid we often eat belong to this suborder. The most produced in our Chinese waters is the Chinese gun squid and the Japanese gun squid are both members of the closed-eye suborder. Their common feature is that there is also a membrane on the outside of the eyeball to protect the eyeball.
Some kind of closed-eye suborder pseudo-squid
Squid cannot be farmed on a large scale at present, but it is fortunate that squid fishing is not difficult. Squids like to hunt in groups and chase the light, and ocean-going squid boats take advantage of this feature to use high-powered lights at night to attract squid schools and then catch them all. The size of the fleet of squid fishing out of the sea is very large, and the brightness of the lights used is also very high, I remember a while ago in Zhihu there was a post, someone took a plane to see a lot of bright spots on the sea, thinking that they encountered some strange events, in fact, it was the light emitted by the squid fleet.
Fleet of squid catchers
Octopus (octopus)
Quick identification: Only 8 feet of the same length and length, no inner shell in the body, most of them have no fins
Common ways to eat: raw, cooked directly, cooked with shredded green onion to eat, barbecue, octopus balls, seafood porridge
Octopus is what we call octopus, because it has only 8 legs, and in some areas it is also called eight belts and eight bands.
Most octopuses have no fins, which deprives them of the ability to swim quickly, and to compensate for this deficiency, some octopuses have evolved webbing between their feet, swimming by paddling through webbed water. Other octopuses move short distances motivated by jet streams of water. Most octopuses simply give up on swimming, and instead of chasing schools of fish and shrimp as fast as squid, they rely on brachiopods to crawl through the reefs on the seabed in search of easier prey such as crabs, shrimps, and shells.
Some kind of octopus that relies on webbing to swim
The inner shells of octopuses have been completely degraded, allowing them to change the shape of their bodies freely without any restrictions, allowing them to walk through the narrow crevices of the rocks on the seabed and encounter the openings of crabs and shrimps, and they can also burrow into them to hunt. And during the break, in order to avoid the total number of predators, the octopus also likes to find a hole to drill into. In Tunisia, Africa, fishermen use octopus's burrowing instincts to catch them. Fishermen make a kind of clay pot with a big mouth and a small belly, tie the jar to the bottom of the sea, and pull it up after a while, often finding an octopus resting at the bottom of the jar.
Jars where Tunisian fishermen catch octopuses
As I said in quick identification, most octopuses have no fins, but there are also some octopuses with very small fins, such as the recently popular "Dumbo Octopus", which is octopus of the octopus family Octopus, which has 2 very small fins.
Dumbo octopus
There is also an octopus that is even more peculiar, its scientific name is ship slug, this octopus actually has an "outer shell"! In fact, this is not a real outer shell, but a protective shell secreted by the female ship slug in order to protect the eggs, and it will be thrown away after laying the eggs, which is fundamentally different from the outer shell of the Nautilus.
Ship slug and its shell
Ghost grubs
Quick recognition: it looks too scary to be identified with other kinds
Common Ways to Eat: Do You Dare to Eat This Too? Under admire, admire
The actual thing looks more frightening, and here it is all replaced by hand drawings.
There is only 1 family and 1 species of ghost grubs, which is a creature that lives in deep water below 1000 meters, and like octopus, it has only 8 feet, but the feet are completely webbed and connected, and the whole is like a cloth bag. On the inside of the foot, there are no suction cups, but all hooks, but these hooks are not used for hunting but only for self-defense. The ghost slug preys on the slender, curly tentacles on the map, and wherever it goes, plankton sticks to the tentacles and is eaten by it.
Hooked feet
How, will it be differentiated?