Bilaterally symmetrical animals
SUPERORDER: Reptiliomorphs
Reptiliomorpha is normally only used to refer to the genera of extinct animals which preceded the amniota, which is the series of animals that contain modern day reptiles, birds and mammals. Although the original reptiliomorphs are described as being amphibious.
Early reptiliomorphs are noted for having elongated jaw structure protruding from the main area of the cranium and skinnier in width to the rest of the skull.
Generally reptiliomorphs' limbs had a five digit structure at their tips.
Basal reptiliomorphs displayed characteristics that even though they were amphibious, displayed reptile like features that distinguishes them from the amphibians we know today. These would include a thicker, scalier skin and advanced development of the limbs and digits.
One significant aspect about reptiliomorphs is that essentially they were the first type of animal this was understood to be land based.
Reproductive changes are also noticed during the evolution of early reptiliomorphs. At some point particular reptiliomorphs developed a method of retaining unborn young within their bodies while they completed what in amphibians is referred to as the larval stage.
Amphibians release their young into shallow waters to complete their formation such as in tadpoles or aquatic eggs. Reptiliomorphs would have either laid a more robust egg which would protect the developing animal outside of water, or simply give birth to a fully formed youngster.
Reptiliomorphs is a general term for amniotes and all of their closest related, reptile like, extinct ancestors.
Amniotes are essentially those tetrapods which have robust eggs whether laid externally, or carried by the parent until birth. This would therefore include reptiles, birds and mammals.
Orders of extinct reptiliomorphs include chroniosuchia, embolomeri, seymouriamorpha and diadectomorpha.
Humans are aminotes.
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Tetrapods who create young which develop in particularly robust eggs. |
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CHRONIOSUCHIA Extinct tetrapods from the Permian period. |
EMBOLOMERI Extinct amphious tetrapods. |
SEYMOURIAMORPHA Extinct semi-aquatic reptile like tetrapods. |
DIADECTOMORPHA Extinct large reptile like tetrapods. |
