sphenoid bone morphology trait basisphenoid morphology trait Any measurable or observable characteristic related to the shape, structure, color or pattern of the part of the base of the cranium between the basioccipital and the presphenoid, which usually ossifies separately in the embryo or in the young, and becomes a part of the sphenoid in the adult; in many animals it persists as a separate bone between the basioccipital bone and the presphenoid bone. basisphenoid bone morphology trait Trait.ontology VT:0000106