How do herrings, sardines, and anchovies differ in classification?

Herrings, sardines, and anchovies are all members of the order Clupeiformes, but they are distinguished by their specific family classifications and anatomical features.12

Classification Differences

• Herrings and Sardines: Both belong to the family Clupeidae. This family includes a wide variety of species, such as pilchards, shads, and menhadens. While "sardine" is a common name often applied to various small clupeids—including the common herring—when they are canned, they are biologically grouped within the same family as herrings.23
• Anchovies: These are classified in a separate family, Engraulidae.42

Key Anatomical Distinctions

The primary physical differences between these groups involve their mouths and teeth:
* Clupeidae (Herrings/Sardines): Members of this family typically have teeth that are either absent or very weakly developed.2
* Engraulidae (Anchovies): Anchovies are generally smaller than clupeids and are distinguished by a very wide mouth and a pointed snout that projects beyond the jaw. Unlike herrings, their mouths almost always extend behind the eye, and their jaws are usually armed with rows of minute teeth.42