Question

In which of the following characters prototherians resemble and metatherians?

• A. Presence of single headed ribs, megalecithal eggs and smallest gestation period
• B. Presence of degenerate corpus callossum, simple cochlea and absence of ear pinnae
• C. Presence of epipubic bones
• D. Presence of abdominal testis and chorio-vitelline placenta

Answer 1

The correct option is C Presence of epipubic bones

• Prototheria consists of egg-laying animals.
• Metatherians are characterized by the presence of an abdominal pouch to carry their underdeveloped young ones for some time after birth. There are some resemblances between the prototherians and metatherians.
• These are- the presence of cloaca, the presence of epipubic bones attached to pubis, absence of true allantoic placenta, and tympanic bulla.
• Near absence of corpus callosum is also seen in both these groups.
• Ear pinnae is absent in prototherians while present in metatherians.

Thus, the correct answer is option C.