Question

Which of the following does not belong to the order Crocodilia.
A. Crocodilus
B. Alligator
C. Gavialis
D. None of the above

Answer 1

Hint:- In the animal kingdom, phylum chordata include two subphylums namely - Vertebrata and non-Vertebrata. Under the subphylum Vertebrata, classes like Pisces, Amphibia, Reptilia, Aves, and Mammalia are included. Class Reptilia includes animals with creeping or crawling mode of locomotion. Reptiles were the first successful terrestrial vertebrates but some are also found in aquatic habitats.

Complete step-by-step solution:-Class Reptilia is classified based on the presence or absence of temporal fossae in the temporal region of their skull and on their number. Living reptiles are divided into two subclasses namely- Anapsida (temporal fossae absent) and Diapsida (two pairs of temporal fossae are present). Further sub-class Anapsida includes order Chelonia and subclass Diapsida includes three orders namely- Rhyncocephalia, Squamata, and Crocodilia.
Among these orders, the order Crocodilia is also called as amphibious reptiles because they are amphibious and live in lakes or rivers. These are the largest modern reptiles. They also have some mammal-like features like the presence of diaphragm, presence of thecodont type of teeth, and the presence of a four-chambered heart. Their body is solid and massive and their skin is covered by bony plates. An elongated snout is also present on which external nares are present at the distal end and they have cover also. The common examples of the order Crocodilia are- Crocodilus (common crocodile), Alligator (Mexican crocodile), and Gavialis (Gharial). Thus the correct answer is option D.

Note:-
Usually, reptiles have a three-chambered heart but the order Crocodilia includes animals that have a four-chambered heart thus they are considered as connecting links between reptiles and mammals. Members of this order do not have a urinary bladder in their bodies. Crocodiles also have a laterally compressed massive tail with clawed and webbed digits.