Question

Pygostyle is -
(a)Largest bone in frog
(b)Bone present in bird’s tail for supporting oil glands
(c)Hind part of snakes
(d)Tip of the vertebral column of fishes

Answer 1

Hint: The pygostyle is a modification of the skeleton present in animals that require lightweight bones for their functions. The modification additionally supports various other parts of the animal. It also contains a structure that secretes a substance.

Complete answer:
The pygostyle is a part of the axial skeleton of the bird. It is a flat bone created by the fusion of the final few caudal vertebrae into a single ossification.
- It serves as the attachment site for tail feathers as well as muscles, thus providing flight stabilization.
- It also contains the uropygial gland that secretes oil that is required for preening.

Additional information:
- Pygostyles appear as two shapes - as rod or dagger-shaped that is found in extinct birds and plowshare shaped found in the living birds.
- The axial skeleton consists of the bones that form the skull, laryngeal skeleton, vertebral column, and thoracic cage. It is adapted for flight in birds.
- The cervical ribs are fused with the vertebrae and are reduced. The ribs also bear uncinate processes to attach muscles that support the scapula.
- The skull of the bird occupies 1 % of the bird’s total skeleton. The eye is surrounded by a ring of tiny bones.
- The bones show many fusions for reducing the weight, as seen in the innominate bone and synsacrum. A synsacrum is a unit formed by the fusion of the posterior thoracic, lumbar, and sacral vertebrae.

So, the correct answer is ‘Bone present in bird’s tail for supporting oil glands’.

Note:
- The largest bone in the frog is the tibio-fibula of the leg bone.
- Birds are endowed with various physical modifications apart from their wings that help in flying, the flight adaptations that are categorized as anatomical and morphological.