Question

what do we mean by procoelus, amphicoelous and acoelous vertebrae?

Answer 1

Procoelus :- concave at the anterior end of the centrum and usually convex at the posterior end of the centrum.
Amohicoelous :- having both the anterior and posterior surfaces of the centrum concave.
Acoelous :- Vertebrae that have centra with flat ends.

Answer 2

A vertebra can be analyzed in terms of the appearance of the ends of the centra (body of the vertebrae) into procelus, amphicoelus, and acoelous vertebrae. The procoelous vertebra has centra with both edges curved. This configuration is prevalent in fish, where most movement is restricted. The vertebrae that have centra with flat edges are known as acoelous, like those in vertebrates. These extended ends of the centra are particularly good for disseminating compressive capabilities.