and constitutes one of the best examples of transition in the fossil record between exclusively swimming aquatic life and forms capable of supported movement out of the water

la competencia con mamíferos carnívoros

following the typical pattern of the family

since it does not appear in specimens identified as females

but not yet fully hardened

Protosiren fraasi Variant:Unprimed and constitutes one of theProtosiren fraasi was one of the earliest marine mammals in the sirenian group, ancestors of modern manatees and dugongs. It lived during the Middle Eocene , approximately 40 million years ago, and its fossils have been found in regions of North Africa and the Middle East, including Egypt and Pakistan. This genus represents a key intermediate stage in sirenian evolution, when these animals were transitioning from a semi aquatic to a fully marine life.