Question

Differences between subclass Archosauria of Reptilia, subclass Archoeornithes of the Aves, subclass Neornithes of the Aves, and subclass Eutheria of the Mammalia. Which group is considered a flying tetrapod that the jaws are toothed and anterior limbs are modified for flight? Please make sure the differences among the subclass' are justifying of a flying tetrapod. Thank you

Answer 1

Subclass Archaeornithes:-Extinct; teeth in both jaws; long, feathered tail and less specialized for flighth(flightless bird). Body is elongated and reptilelike, forelimb had 3 clawed digits,small brain and eyes,nonpneumatic bones.

Subclass Archoeornithes of the Aves:-It is links between reptiles and birds i,e Lizard, which belong to Jurassic period. All the members have become extinct.Wings are ill developed, i.e. capacity of flying was very less.Pygostyle ,Keel and Uncinate processes on ribs was absent.There were present 3 - 3 clawed digits of forelimb at the free edges of wings.Teeth were present in the jaws of skull.

Subclass Neornithes of the Aves:- This class includes live animals and extinct animals of post jurassic period.There wings are well developed which are used in flying .There is presence of pygostyle, keel. Digits of forelimbs are fused and claws absent.Except some species ,rest all the birds are toothless.

Subclass Eutheria of the Mammalia:-These were evolved in Triassic period of Mesozoic era. Coenozoic era is golden era of mammals.The members of this class are cosmopolitan.These are highly developed animals.

Their skin is thick, water proof, glandular. So many types of glands are present in the skin as sweat glands, oil glands or sebaceous glands and mammary glands.Mammary glands (Modified sweat glands) are found in females for baby feeding.Teeth are fixed in sockets in the buccal cavity, so teeth are called Thecodont.

The tetrapods is living on land and Members include the amphibians, reptiles, birds, and mammals.

Birds are warm-blooded and although most are capable of flight, others are sedentary and some are flightless