Gasterosteoidei is a suborder of ray-finned fishes that includes the sticklebacks and relatives. It is currently classified in the order Scorpaeniformes.
Gasterosteoidei is treated as a suborder within the order Scorpaeniformes in the 5th edition of Fishes of the World, but in other classifications it is treated as the infraorder Gasterosteales.
Historically, Gasterosteoidei was called the Gasterosteiformes. Recent studies show that the more typical members of that group (like scorpionfishes) arecloser to the "true" Gasterosteiformes, so we can see why it was changed.
These fish have the possession of an upper jaw and a well developed upward pointing process on the premaxilla. They have small mouths. The body usually has dermal plates.
Here are two of the extinct genera of the Gasterosteoidei: