holostyly
Holostyly is a term used in anatomy and paleontology to describe a specific type of jaw suspension in vertebrates. In holostyly, the upper jaw, or palatoquadrate cartilage, is directly and immovably fused to the skull. This contrasts with other forms of jaw suspension where the upper jaw is connected to the skull through a series of bones, allowing for movement.
This type of jaw suspension is considered primitive and is found in some of the earliest jawed
The rigid, fused nature of the holostylic jaw suggests a different feeding mechanism compared to vertebrates