Knowra Castorocauda Castorocauda Castorocauda is an extinct semiaquatic docodont mammaliaform genus from the Middle Jurassic. Its fossils preserve a broad, beaver-like tail and evidence of fur, showing that early mammaliaforms occupied aquatic habitats.
Docodonta : An extinct group of mammaliaforms known chiefly from the Jurassic and Cretaceous periods. Castorocauda is classified within this group, whose members had diverse teeth and ecologies.
Semiaquatic locomotion : Movement by an animal that regularly travels both on land and in water. Castorocauda's limbs and tail suggest adaptations for swimming as well as terrestrial movement.
Castorocauda lutrasimilis : The type and only formally named species of the genus Castorocauda. This species is represented by the specimen that revealed the genus's distinctive body features.
Mesozoic mammal diversity : The variety of body sizes, anatomies, and ecologies among mammals and mammaliaforms of the Mesozoic Era. Castorocauda documents aquatic specialization within this broader evolutionary diversity.
Mammaliaformes : The evolutionary group that includes mammals and their closest extinct relatives. This broader lineage places Castorocauda among early relatives of mammals.
Beaver tail : A broad, flattened tail used by beavers for swimming, balance, and communication. Castorocauda's broad tail resembles a beaver's, though its precise function is uncertain.
Juramaia : An extinct mammaliaform from the Jurassic of China, known from a small fossil skeleton. Juramaia is another early mammaliaform from China, but represents a different body plan.
Mesozoic mammal revolution : A proposed burst of ecological and anatomical diversification among mammals during the Mesozoic Era. Its specialized aquatic traits contribute evidence that mammaliaforms diversified early.
Middle Jurassic : The interval of geologic time from about 174 to 163 million years ago. Castorocauda fossils date to this interval, when its habitat and contemporaries existed.
Webbed feet : Feet with skin between the digits that can increase propulsion in water. Impressions of webbing support the interpretation that Castorocauda was adapted for swimming.
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