Explanation:
A
Amphicoelus is veritebral centrum that have both the anterior (front) and posterior (back) end of the vertebral centrum are concave or hollowed out. this creates a biconcave shape, resempling a fingre light or an hourglass.
In birds, amphicoelus present near neck region.
Procoelous vertebrae that having a concave or hollowed out anterior (front) end of the vertebral centrum and convex or rounded posterior (back) end.
Procoelous vertebralcentyum is commonly found in the trunk and fail regions of many urodeles.