Knowra Seymouria Seymouria Seymouria is an extinct genus of Permian tetrapods combining a robust, reptile-like skeleton with traits associated with amphibians. It is classified as a stem amniote, outside the living amphibian and reptile lineages.
Tetrapod : A vertebrate with four limbs or descended from an ancestor with four limbs. Seymouria belongs to the early diversity of four-limbed vertebrates.
Seymouria baylorensis : A species of Seymouria known from Permian fossil deposits in Texas. This species supplied much of the classic anatomical evidence for the genus.
Vertebral column : The series of vertebrae that supports the trunk and protects the spinal cord in vertebrates. Seymouria's strong vertebral column supported its weight on land.
Permian : A geologic period lasting from about 299 to 252 million years ago, between the Carboniferous and Triassic. Seymouria lived during this period, when terrestrial vertebrate groups diversified.
Reptile : A vertebrate in the sauropsid lineage, including turtles, lizards, snakes, crocodilians, and birds. Seymouria looked reptile-like but did not belong to the reptile lineage.
Amniote : A vertebrate whose embryo develops within an amnion and associated extraembryonic membranes. Seymouria lies near the evolutionary origin of this group but is not itself an amniote.
Seymouria sanjuanensis : A species of Seymouria known from Permian deposits in New Mexico. Its fossils extend the genus's known range in North America.
Pectoral girdle : The bones connecting the forelimbs to the trunk in a vertebrate. Its robust shoulder region helped bear weight during terrestrial locomotion.
Early Permian : The first epoch of the Permian Period, lasting from about 299 to 273 million years ago. Most well-known Seymouria fossils come from Early Permian deposits.
Lissamphibia : The clade containing all living amphibians: frogs, salamanders, and caecilians. Seymouria is not a member of the modern amphibian lineage.
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