Question

give the classification of class - Aves

Answer 1

Based on characters of Aves Class is divided into 2 sub-classes.

Sub class: i) Archeornithes and Subclass ii) Neornithes

1. Sub class Archeornithes:

In this subclass extinct birds are included. Those birds were alive in Mesozoic era.
These show a long tail with 13 or more than 13 caudal vertebrae.
Pygostyle is absent.
Meta carpals are free. The free fingers of fore limb will end with claws.
Thecodont teeth are seen.
Eg: Archeopteryx, Archeormis

2. Sub class Neornithes:

This subclass includes both extant and extinct birds.
Tail ends in pygostyle. The rectrices are arranged r a semi circular around pygostyle.
Teeth are absent in many forms.
Sternum is well developed. It shows a keel to which flight muscles are attached.

This subclass is divided into 4 super orders.

Odontognathae
Palaeognathe
Impennae
Neognathae

1. Super Order: Palaeognathae:

These are flightless birds.
They are more in numbers.
Wings are reduced or absent.
Teeth are absent.
Caudal vertebrae are free.

This super order is divisible into 7 orders.

1. Order: Struthioni:

Ex: Struthio camelus (Two toed African Ostrich (or) Ostrich)

Large flight-less bird.
Feathers are less.
They show two toed hind limbs.
Sternum is without keel.
Neck is very long and flexible.
Pygostyle is absent.
These birds are good runners.