Characteristics of Crustaceans

Thursday, June 2, 2022

Characteristics of Crustaceans


Humans have 206 bones in their body. The average cat has 244 bones in its body. Snakes, the most bony animals, have around 1800 bones! Can you guess how many bones a lobster has?


A lobster belongs to the phylum Arthropoda and the Subphylum crustacea. Arthropods are the most abundant category of animals on earth. It is estimated that between 75-84% of all animals on earth belong to this category. Examples of crustacea  include: lobsters, crabs, shrimp, and krill

What are some traits of crustaceans?

  • First crustacea are arthropods.


  • All arthropods have several traits in common. Let’s take a look at these common traits.


  • Exoskeleton: Remember the question from the beginning? The answer to “How many bones does a lobster have?” is none! Arthropods do not protect their organs with a skeleton made of bones. Instead, they have a hard outer covering called an exoskeleton. An exoskeleton is made of chitin, a complex sugar that binds to proteins. The exoskeleton protects the arthropod and allows it to sense its surroundings, supports the organism, and is even involved in excretion. When the arthropod grows, it must periodically shed the old exoskeleton and grow a new exoskeleton in a process called molting. 


  • Bilateral symmetry: All arthropods have bilateral symmetry. This means that if a line was drawn straight down the middle of their bodies, both sides would be identical to one another. Humans also have bilateral symmetry. 


  • Bodies with Regions: If you take a look at a spider or an insect, you will notice that their body is made up of more than one segment. A spider has two segments, and an insect has three: a head, a thorax, and an abdomen.


  • Segmented appendages: What is an appendage? An appendage is a portion of an arthropod that sticks out from its body and has a function. Examples of appendages include legs, arms, and antennae.


  • The appendages of arthropods are made of many joints. A joint is the location where two parts meet. Humans also have joints where our bones come together.

Most crustaceans live in water, but some live on land. 


In addition crustacea,


  • The head has two compound eyes,


  •  Two pairs of antennae,


  •  Three pairs of mouthparts


  • The abdominal segments have at least five or more swimmerets (swimming legs)


 Common examples of Crustaceans include, 












Fiddler crab




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