Actually, myMEGusta prefers that her crustaceans – prawns and shrimp and langoustines – arrive intact, spiny heads and all.
When impeccably fresh and properly cooked, the heads of these little animals are briny and sweet, meant to be tasted then tossed. When the little beasts need to be cleaned before cooking, the heads and shells can be saved, accumulating in the freezer until critical mass is achieved and a delicious shrimp stock is in the offing, perhaps as the base for a bouillabaisse or seafood risotto.
There’s a lot of confusion about what the difference is among these animals, if only because they look a lot alike.
First, shrimps and prawns are separate species from the langostino/langoustine group which, include spiny lobsters which are only distantly related to North Atlantic, or “Maine” lobsters. And this is why so many Northerners complain about the “lobster” in Florida and “lobster tails”. They are different animals with different flavor characteristics.
The main difference between shrimp and prawns lies in who you are talking to. In reality, they are two species, differentiated by the shape of their claws and other details, but constantly interchanged in the real world of fish markets and restaurants. In the US, shrimp tend to be smaller, but giant shrimp are often marketed as prawns on menus, especially Chinese. In the UK, they’re all called prawns.
Scampi used to be large shrimps (or prawns) grilled in butter or olive oil and garlic as they might be when freshly caught from the Mediterranean Sea in Italy. Now the word connotes anything with those ingredients, even the tiniest of shrimp or chicken, cooked in any fashion and sometimes with wine, breadcrumbs or other ingredients in addition to the basics.
Langostinos are not widely known in the US, usually found clean and frozen, ready to toss into the pan.
I discovered my favorite way to eat langoustines years ago in Paris: Presented on a giant platter, heads on and fresh from the market with a bowl of freshly made mayonnaise for dipping. First break off the head (taste and toss), then liberate the tail meat and dip. Perfection.