dentarias

Dentaries, or dentary bones, are the principal bones of the lower jaw in most jawed vertebrates. They form the major, tooth-bearing portion of the mandible and typically articulate with other bones that make up the jaw joint in different lineages. In many early or non-mammalian tetrapods, the dentary is one of several bones composing the lower jaw, with joints formed between it and bones such as the articular.

Structure and function: The dentary carries the teeth along its alveolar margin and provides attachment surfaces for jaw-closing muscles. Its shape, size, and processes (such as the coronoid and condylar regions) vary widely and reflect different feeding strategies. In reptiles and amphibians, the dentary often forms a joint with the articular bone at the back of the jaw.

Evolutionary significance: A key evolutionary feature in mammals is the shift from a multi-bone lower jaw to a dentary-only jaw jointed to the squamosal bone. In this transition, the articular and quadrate bones were repurposed as the malleus and incus, the auditory ossicles of the middle ear, while the dentary became the sole lower-jaw element. This change improved jaw mechanics and played a role in mammalian hearing.

Terminology and usage: The plural in English is typically dentaries; in some languages and texts, dentarias may be used. The term derives from the Latin dens, meaning tooth, reflecting the dentary’s role as the tooth-bearing element of the lower jaw.