Re: What is the difference between shrimp and prawns?

Hi there,

What you've actually asked is a big question all about Crustacean taxonomy.

Forget "shrimp" and "prawn" - I'll quickly go through how Crustaceans are 
classified. Hopefully I'll even make it clear!

Here goes:

Ok. Crustaceans are Arthropods that have an ecoskeleton (like a permanent 
suit of armour). It's not water tight however, which differentiates them 
from insects. Crustaceans also have gills and a special aquatic larval 
stage.

Dividing Crustaceans up gives us 6 classes. Basically, these groups cover:

* Copepods (planktonic swimmies)
* Ostrocods (small marine swimmies)
* Branchiopods (brine shrimp and Daphnia)
* Barnacles
* Branchiurans (parastic)
* Malacostracans (lobster, crabs, woodlice etc.)

It's the Malaconstracans you've asked about, so they divide even further 
(a very diverse group!)

Here we have Isopods, Amphipods and Decapods. It's the Decapods (meaning 
10 legs) that contain all the lobsters, crabs, shrimp and prawns.

So, Mantis shrimp, king prawns, and snapping shrimp are all Decapods 
(think of that classic "prawn" body plan - long slender body with lots of 
legs and the head at the front with all the antennae). They're all quite 
closely related - at least with respect to their "order". After "order", 
we divide organisms up into "family", then "genus" and "species". 

I hope this quickly explains the Phylum Crustacea...to answer your 
question in one statement:

Prawns and shrimp are very closely related - belonging to the same order 
(Decapoda). Both can occur in marine, estuarine and freshwater 
environments, depending in the species in question.

cheers,

Alastair