Final answer:
The name of the bony defect below the mandibular canal that represents the submandibular fossa is called the mandibular fossa.
Step-by-step explanation:
The bony defect that would be found in adolescent males, below the mandibular canal, and represents the submandibular fossa is called the mandibular fossa. This oval-shaped depression is located on the external base of the skull, just in front of the external acoustic meatus. The mandible joins with the skull at this site as part of the temporomandibular joint, which allows for movements of the mandible during opening and closing of the mouth.