Bilaterally symmetrical animals
Rhipidistia are special in that they are considered to be the crown group of all amphibians, reptiles, birds and mammals. Crown group describes a type of animal from which all other species of animal are thought to have originated from. What makes rhipidistia special is that in its original form, it was a fish.
Rhipidistia have definite lungs enabling them to breathe air should it be required.
Rhipidistia date back over 410 million years on planet Earth.
The rhipidistia can be split into two groups, each of which have species alive today.
Tetrapodomorpha are the branch of rhipidistia which went on to become the amphibians, reptiles, birds and mammals we know today.
The alternative group is the dipnomorpha group which is represented in today's world by the lungfish.
Dipnomorpha have advanced lung development but essentially remained aquatic, living in freshwater.
Tetrapodomorpha's fins developed the first type of humerus bone which allowed in the fin to have more versatility for movement on hard surfaces.
Humans belong in the tetrapodomorpha group.
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Animals with advanced fins with a humerus. |
DIPNOMORPHA Fish with advanced lungs which can breathe air. |
