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all Lissamphibians in a sentence

1. Newer research indicates that the common ancestor of all Lissamphibians lived about 315 million years ago, and that stereospondyls are the closest relatives to the caecilians.

2. Some, if not all, lissamphibians share the following characteristics.

3. Recently, the theory that temnospondyls were the ancestors of all lissamphibians has gained wide support.

4. If Chinlestegophis is indeed both an advanced stereospondyl and a relative of caecilians, this means that although all lissamphibians are descended from temnospondyls, the different groups would have descended from different branches of the temnospondyl family tree.

5. The other two hypotheses are the "lepospondyl hypothesis", which places all lissamphibians as the closest relatives of a group of lepospondyls called lysorophians, and the "temnospondyl hypothesis", which has all lissamphibians derived from amphibamid temnospondyls like Gerobatrachus.

6. When all lissamphibians are considered to be descended from microsaurs, Trihecaton is equally likely to be close to the Microbrachis + Hyloplesion + Holospondyli branch, or alternatively in the main microsaur group intermediate between ostodolepidids, gymnarthrids, and Saxonerpeton.

7. As such, these results form the basis for a fourth major hypothesis regarding lissamphibian origins, namely that all lissamphibians are derived from temnospondyls, but that batrachians (frogs and salamanders) are descended from dissorophoids, whereas caecilians came from Chinlestegophis-like taxa nested among the stereospondyls.

8. The use of a modified version of the Pardo et al. matrix by Schoch et al. (2020) recovered a single origin of all lissamphibians from dissorophoids, consistent with the historic "temnospondyl hypothesis."