Amphibians To Amniotes (early Reptiles)
The Amphibians → Reptiles Evolutionary Series | |||||
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Appearance | Taxa | Relationships | Status | Description | Image |
326 - 318 Ma |
Genus:
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One of the early reptile-like amphibians | Amphibian | A large, somewhat lizard-like labyrinthodont with a deep skull, laterally placed eyes and five digits to each foot. | |
??? Ma |
Genus:
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The order Diadectomorpha is the sister group of the amniotes. | The Limnoscelis was originally described as a "cotylosaur" (early reptiles) together with the other diadectomorphans. Today the large-bodied diadectomorphs are thought to have had a larval stage, falling close to, but just outside the amphibian/reptile divide. | A large, predatory reptile-like amphibian. The limbs are extremely heavily built, indicating it fed on slow moving prey. | |
??? Ma |
Genus:
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Uncertain phylogeny, possibly a Seymouriamorph or Diadectomorph | Amphibian | A medium sized, probably herbivorious animal | |
350 Ma |
Genus:
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Uncertain phylogenetic position. Westlothiana may be a small-bodied diadectopmorph, falling just outside the amphibian/reptile divide | Originally described as the first reptile, it is now considered an advanced reptile-like amphibian. | Small, probably insectovorious animal. The body and tail was long, the limbs small, somewhat like a modern skink. | |
320-305 Ma |
Genus:
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Possibly allied to the Diadectomorpha, or belinging to a sister group to Diadectomorpha and Amniota | Likely an amphibian | Smallish, likely carnivorious. | |
340 Ma |
Genus:
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The fragmentary nature of the fossil (it lacks a cranium) makes an exact phylogenetic position hard to establish. | Possibly the first animal with an amniote egg, and thus the first reptile. | Small lizard-like animal, the first known tetrapod to possess claws, indicating it has reptilian type skin with scutes. | |
315 Ma |
Genus:
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One of several small, basal reptile genera | Reptile | An early anapsid reptile, considered to be ancestral to both the synapsid and sauropsid lines, and thus the oldest representative of the crown group amniotes. | |
312 - 304 Ma |
Genus:
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One of several small, basal reptile genera | Reptile (most likely a sauropsid) | An early anapsid reptile. In phylogenetic analysis it falls on the sauropsid side, it is thus likely a progenitor of the diapsids |
Read more about this topic: List Of Transitional Fossils