Synapsida
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Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse gro
Synapsid diversity 3
Skull of Cotylorhynchus, a basal synapsid
Diagram showing synapsid jaw evolution from early "pelycosaur" synapsids to modern mammals
The sea otter has the densest fur of modern mammals.
Amniote
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Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibi
Synapsida
…Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant reptiles and birds). Synapsids have a single lower temporal fenestra, an…
Amniota
Archaeothyris, one of the most basal synapsids, first appears in the fossil records about 306 million years ago.
By the Mesozoic, 150 million years ago, sauropsids included the largest animals anywhere. Shown are some late Jurassic dinosaurs, including the early bird Archaeopteryx perched on a tree stump.