Question

Classify living reptiles upto orders giving characters and examples

Answer 1

Answer:

Reptiles represent the first class of vertebrates fully adapted for terrestrial life can be live indefinitely out of water. They have no diagrostic characteristics of their own that immediately separate them from other classes of vertebrates. The characters of reptiles are in fact a combination of characters that are found in fish and amphibians on one hand and in birds and mammals on the other. The class name refers to the mode of locomotion (L., repere or reptum, to creep or crawl).

The class reptilian has been classified into five major sub-classes on the basis of presence or absence of certain openings in the temporal region of skull. There are more than 7,000 living and several extinct species which are grouped into 16 orders under the five sub-classes. Out of the 16 orders 4 are living and others are extinct.

Sub-class-I – ANAPSIDA

i) Roof of skull is complete and no temporal openings.

This sub class includes one living order.

Order – 1 – Chelonia or Testudinata

(i) Body is short, broad and oval.

ii) Limbs clawed and webbed and paddle like.

(iii) Body encased in a firm shell of dorsal carapace and ventral plastron, made of dermal bony plates.

(iv) Thoracic vertebrae and ribs usually fused to carapace.

(v) No sternum is found.

Answer 2

Cold-blooded animals, reptiles breathe through their lungs and have scales or scutes covering their bodies.

• The Reptilia class can be classified into three subclasses namely, Anapsida, Parapsida, and Diapsida.

Anapsida

• Without any temporal fossae, the dermal bones provide a full roof over the skull.
• Cotylosauria and Chelonia are the subgroups of these.
• The way that modern chelonians retract their heads within their shells is used to classify them.
• This group includes terrapins, turtles, and tortoises.

Parapsida

• One temporal fossa is located high up on the skull of these reptiles.
• This form of skull was seen in protosaurs, nothosaurs, and placodonts.
• Ichthyosaurs and Plesiosaurus were the two largest of these groups.
• When various other reptiles, including dinosaurs, perished at the end of the Cretaceous epoch, they went extinct as well.

Diapsida

• The skull has two temporal vacuities.
• Of all reptiles, they are the most varied.
• This group consists of pterosaurs and dinosaurs.
• Archosauria and Lepidosauria are the two main categories into which these are divided.
• Crocodile, chameleon, etc. are some examples in this class.

Some of the orders of Reptilia include-

1. Order Cotylosauria (extinct): Examples- Diadectes, Procolophon, etc.
2. Order Chelonia: Examples- Turtles, Tortoises, Testudo, Cistudo, etc.
3. Order Rhynchocephalia: Example- Sphenodon.
4. Order Squamata: Example-Lizards, Snakes.
5. Order Crocodilia: Examples- Crocodiles, Alligators, Crocodylus, Gavialis, etc.

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