Question

Give a node-based definition for the taxon name Archosauria, a group that includes all extant species of crocodylians and birds.

Give a stem-based definition for the name Archosauromorpha, which includes Archosauria and its extinct close relatives.

Answer 1

Answer:

Archosauria:

Archosauria is term used for the group of amniotes. Archosauria word is made from two words Archon + Saurian; archon is Greek word which meaning is recent creator or say most recent ancestor and saurian meaning is suborder of lizards.

Archosauria is the term used for those organisms having phenotypic character is very much similar to the lizards/ crocodilians as well as birds.

This is the node based definition of the Archosauria.

Basically Archosauria origins accepted by researcher Russia because in ancient time mammals like reptiles was found in Russia. After that study was moved further on behalf of Russian theory on Archosauria.

Many of species in recent has been vanished from the earth.

Phenotypic Character:

Most important phenotypic character of the Archosauria is they have a hole in central part of skull on the upper side of nostrils.

Archosauromorpha:

Archosauromorpha is morphologically most similar to the Archosauria but the measure difference between them is they are not from predecessor of crocodilians as well as birds.

Yet morphological character are very much similar but one morphological character is also different from the Archosauria is teeth shape. Both are differ teeth shape and size.

It includes the 4 sub-groups also

1. Prolacertiformes

2. Choristodera

3. Rhynchosauria

4. Trilophosauria.