Cuttlefish squids shortfin squids

Can you distinguish cuttlefish, squids and broadtail shortfin squids? These molluscs are cephalopods belonging to the order Decapoda, that means they have ten arms.
Cuttlefish, squids and shortfin squids show two types of arms: 8 are short and sturdy and present numerous suckers along their inner side. The other two are called tentacles , they are long and thin and bear suckers only at their apex. The two tentacles are not always visible because they are hidden inside a pouch and they come out only during the prey capture.
Unlike octopus and curled octopus, suckers have peduncles and are denticulate.
Arms surround the mouth which shows two beak-like jaws able to tear off prey tissues.
This clip shows the beaks of cuttlefish, squids and shortfin squids.
Cuttlefish, squids and shortfin squids possess a radula as most of cephalopods. The radula is a chitinous and denticulate ribbon placed inside the mouth and used to grind food.
Now well see the main differences between these molluscs.
The body of the cuttlefish is large and pudgy, while it is slender in squids and shortfin squids.
In all three animals the mantle surrounding the body shows a pair of flattened structures called fins. However, in cuttlefish, fins are not evident and surround all the body, while, in squids, fins are large and triangular and are present along the distal half of the body. The triangular fins of shortfin squids instead originate near the body posterior extremity.
Observing eyes, we notice that only cuttlefish has a w-shaped pupil.
Now we compare the shells. These molluscs have an internal shell covered by the mantle. Cuttlefish present the characteristic cuttlebone made of calcium carbonate crystals in the form of aragonite. The cuttlebone is divided in chambers containing gas and it is useful for buoyancy and support.
Squids and shortfin squids have a more reduced shell called pen. The pen is transparent, slender and made of chitin. The video shows how to extract the squids pen. The shortfin squids pen is similar to that of the squid but thinner especially in the central portion.

Category:

Pets & Animals

Tags:

• cuttlefish
• squids
• broadtail
• shortfin
• anatomy
• morphology
• zoology
• practise
• marine
• biology
• fishing
• shell
• pen
• cuttlebone
• bone
• beak
• radula
• sucker
• ink
• cephalopod
• molluscs

[filmedonkohtao]

Lovely learn something new ever day.I found this short very helpful in understanding cephalopods.

[Amphinema]

@filmedonkohtao Thank you very much! I visited your website and saw the page concernig the underwater videography course in Koh Tao, I would like to follow this course in the future!

[SenyaSaysSo]

My parakeets and conure eat cuttlebone lol. Guess you never really know who is predator and who is prey :P