Question

Diapsid skull is found in which of the following groups?
A. Crocodile, turtle, and Seymour
B. Sphenodon, crocodile, and viper
C. Natrix, Draco, and turtle
D. Calotes, cobra, and Varanosaurus

Answer 1

Hint: Diapsid is a group of animals that are tetrapods. The diapsid skull is that which is seen in reptiles but not all reptiles have diapsid skulls. The characteristic feature of the diapsid skull is that it contains two holes at the back of the eyeballs on each side. The ‘di’ in diapsid means two and ‘apside’ means holes.

Complete answer:
The diapsid group of animals consists of reptiles and mammals that are tetrapods having four limbs. Their characteristic feature is the presence of two holes at the back of their eyes on both sides of the skull. They are a diverse range of animals including crocodilians, lizards, tuatara, snakes, birds, and turtles (modified Diapsids). The unique arrangement of the diapsid skull allows these animals to have large and strong jaws attached to their skull. This arrangement enables a wide jaw opening in these animals. Crocodiles are large semi-aquatic reptiles having the characteristic Diapsid skull and wide jaw. Tuataras are reptiles including Sphenodon species. They resemble lizards but are different species. They are thought to be evolved in the early Mesozoic era. Also, many species of Tuatara are extinct and the left species are regarded as endangered. Viper is a poisonous snake species. They have a characteristic Diapsid skull as seen by their wide jaws. Thus, Sphenodon, crocodile, and viper are Diapsids.
So, the right answer is option B.

Note: Around 7,925 diapsid reptile species are known to exist excluding birds. Earlier diapsids were classified as a subclass of class reptilia. Modern studies of reptile relationships suggest that diapsid term can be referred to as the crown group of all modern diapsid reptiles but not their extinct relatives. The diapsids are thought to first emerge in the Pennsylvanian period.