Question

Identify the pair having amphicoelous vertebrae
A. Ornithorhynchus and Macropus
B. Ophiophagus and Tropidonotus
C. Scoliodon and Ichthyophis
D. Crocodylus and Hemidactylus

Answer 1

The vertebral column is a component of the axial skeleton that supports and balances the body on its axis. The axial skeleton of primitive chordates was a single rod-like notochord, but in later groups, a vertebral column made up of a series of vertebrae replaced it, allowing for greater flexibility and bending of the body.

Complete answer:
Amphicoelous vertebrae is a type of vertebrae in which the centrum of the vertebrae is concave on both anterior and posterior surfaces. It is a type of vertebrae in which there is the presence of concavity on the anterior surface and posterior surface on the centrum, so a biconcave structure is found on both the surfaces. Centrum is a part of the vertebrae which shows movement and gives strength and also helps in the attachment of the other vertebrae to form a rigid vertebral column.
This can be found in groups of fishes, amphibians which have tails like in URODELA group and in some reptiles.
Option A: Ornithorhynchus and Macropus : Ornithorhynchus and Macropus , both come under mammals, platypus and kangaroo respectively, it will not have this type of vertebrae.
Option B: Ophiophagus and Tropidonotus :Ophiophagus and Tropidonotus both are reptiles and snakes so they do not contain Amphicoelous vertebrae.
Option C: Scoliodon and Ichthyophis : Scoliodon is a genus of requiem sharks in the Carcharhinidae family. It was previously thought to consist of only one Indo-Pacific species, the spadenose shark, but recent taxonomic research has discovered another species, the Pacific spadenose shark.
Ichthyophis is a caecilian genus (limbless amphibians, also known as Asian caecilians) found in Southeast Asia, the southern Philippines, and the western Indo-Australian Archipelago.
Thus, Scoliodon and Ichthyophis have a concave centrum (vertebral centrum) on both the anterior and posterior surfaces.

Hence, The correct answer is option C. It has amphicoelous vertebrae.

Note:
Salamanders have a number of specialized features associated with the last caudocranial and first caudal vertebrae, which are usually where the break occurs. The articular surfaces of heterocoelous vertebrae are saddle-shaped. This configuration is seen in turtles that retract their necks and birds because it allows for extensive lateral and vertical flexion motion without stretching or wringing the nerve cord around its long axis.