Protostyly

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Protostyly

 

the hypothetical original type of jaw articulation found in the ancestors of gnathostomatous vertebrates. In such jaws, the mandibular and hyoid arches are not interconnected but are attached to the axial cranium only by their upper ends. In the course of evolution the protostyly was replaced by superior types of jaw articulation.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.